EVOLVING ASPECTS OF ENDODONTIC TREATMENT

LEIF K. BAKLAND, DDS

EVOLVING ASPECTS OF

ENDODONTIC TREATMENT

JournaC A L I F O R N I A D E N T A L A S S O C I A T I O N

Bacteria and the Root Canal System

Cone Beam CT and Endodontic Treatment

Prospects of Regrowing Pulps

April 2018

“I was convinced from my

first order. The savings are

very impressive!”—Dr. R in San Luis Obispo County, CA

More shoppers. More savings for everyone.

Join CDA members who are enjoying less overhead and more control. They’re sharing in big group purchasing benefits by shopping the TDSC Marketplace.

See 20% average savings,* plus free shipping, on 25,000 dental supplies from authorized vendors.

Shop, save and share today at tdsc.com.

*Price comparisons are made to the manufacturer’s list price. Actual savings on the TDSC Marketplace will vary on a product-by-product basis.

The DentistsServiceCompany

C DA J O U R N A L , V O L 4 6 , Nº 4

A P R I L 2 0 1 8 207

April 2018

D E PA R TM E N T S

F E AT U R E S

Evolving Aspects of Endodontic Treatment

An introduction to the issue.Leif K. Bakland, DDS

Can We Eliminate Microorganisms From the Root Canal System?

This article discusses the current status of irrigation effectiveness and progress.Markus Haapasalo, DDS, PhD

Can Use of Cone Beam Computed Tomography Have an Effect on Endodontic Treatment?

This paper reviews the most updated guidelines for use of CBCT to illustrate the effects this has on clinical endodontic practice.Robert S. Roda, DDS, MS

Can We Regrow Pulps?

This manuscript discusses techniques for managing teeth that will allow continued root development in young patients. Paul V. Abbott, BDS, MDS

Implant Dentistry and Endodontics: Can There Be a Mutually Beneficial Relationship?

This article reports on the value of dental implants when indicated and the coexistence of endodontics and implant dentistry.Tory Silvestrin, DDS, MSD, and Charles J. Goodacre, DDS, MSD

221

227

237

249

260

The Editor/The TDSC Marketplace and You

Letter to the Editor

Impressions

RM Matters/Spring Cleaning Isn’t Limited to the Offi ce: Update Patient Records To Mitigate Risks

Regulatory Compliance/Managing Emergency Patients

Tech Trends

209

213

215

269

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208 A P R I L 2 01 8

Volume 46, Number 4 April 2018

JournaC A L I F O R N I A D E N T A L A S S O C I A T I O N

CDA classifieds work harder to

bring you results. Selling a practice

or a piece of equipment? Now you

can include photos to help buyers

see the potential.

And if you’re hiring, candidates

anywhere can apply right from

the site. Looking for a job? You can

post that, too. And the best part—

it’s free to all CDA members.

All of these features are designed to

help you get the results you need,

faster than ever. Check it out for

yourself at cda.org/classifieds.

CDA Classifieds. Free postings.Priceless results.

CDA classifieds work harder to

bring you results. Selling a practice

or a piece of equipment? Now you

CDA Offi cersNatasha A. Lee, DDSPRESIDENT

[email protected]

R. Del Brunner, DDSPRESIDENT-ELECT

[email protected]

Richard J. Nagy, DDS VICE PRESIDENT

[email protected]

Judee Tippett-Whyte, DDS SECRETARY

[email protected]

Steven J. Kend, DDSTREASURER

[email protected]

Craig S. Yarborough, DDS, MBASPEAKER OF THE HOUSE

[email protected]

Clelan G. Ehrler, DDSIMMEDIATE PAST PRESIDENT

[email protected]

ManagementPeter A. DuBoisEXECUTIVE DIRECTOR

Jennifer GeorgeCHIEF MARKETING OFFICER

Carrie E. GordonCHIEF STRATEGY OFFICER

Alicia MalabyCOMMUNICATIONS

DIRECTOR

EditorialKerry K. Carney, DDS, CDEEDITOR-IN-CHIEF

[email protected]

Ruchi K. Sahota, DDS, CDEASSOCIATE EDITOR

Brian K. Shue, DDS, CDEASSOCIATE EDITOR

Gayle Mathe, RDHSENIOR EDITOR

Leif K. Bakland, DDS GUEST EDITOR

Andrea LaMattina, CDEPUBLICATIONS MANAGER

Kristi Parker JohnsonEDITORIAL SPECIALIST

Blake EllingtonTECH TRENDS EDITOR

Jack F. Conley, DDSEDITOR EMERITUS

Robert E. Horseman, DDSHUMORIST EMERITUS

ProductionVal B. MinaSENIOR GRAPHIC DESIGNER

Randi TaylorSENIOR GRAPHIC DESIGNER

Upcoming Topics May/General Topics

June/Millennial Dentists

July/Student Research

AdvertisingSue Gardner ADVERTISING SALES

[email protected]

Permission and ReprintsAndrea LaMattina, CDEPUBLICATIONS MANAGER

[email protected]

Manuscript Submissionswww.editorialmanager.com/jcaldentassoc

Letters to the Editorwww.editorialmanager.com/jcaldentassoc

SubscriptionsSubscriptions are available only to active members of the Association. The subscription rate is $18 and is included in membership dues. Nonmembers can view the publication online at cda.org/journal.

Manage your subscription online: go to cda.org, log in and update any changes to your mailing information.Email questions or other changes to [email protected].

published by the California Dental Association 1201 K St., 14th Floor Sacramento, CA 95814 800.232.7645 cda.org

Journal of the California Dental Association (ISSN 1043–2256) is published monthly by the California Dental Association, 1201 K St., 14th Floor, Sacramento, CA 95814, 916.554.5950. Periodicals postage paid at Sacramento, Calif. Postmaster: Send address changes to Journal of the California Dental Association, P.O. Box 13749, Sacramento, CA 95853.

The California Dental Association holds the copyright for all articles and artwork published herein. The Journal of the California Dental Association is published under the supervision of CDA’s editorial staff . Neither the editorial staff , the editor, nor the association are responsible for any expression of opinion or statement of fact, all of which are published solely on the authority of the author whose name is indicated. The association reserves the right to illustrate, reduce, revise or reject any manuscript submitted. Articles are considered for publication on condition that they are contributed solely to the Journal.

Copyright 2018 by the California Dental Association. All rights reserved.

Stay Connected cda.org/journal


A P R I L 2 0 1 8 209

Editor

When I was a child, we would order our shoes from the Sears, Roebuck and Company catalog. I

can remember my mother tracing around my foot to record my footprint on a piece of paper that she would then send to the mail-order company. After some weeks, the box would arrive with my new penny loafers. It was easy and convenient. We did not have to drive into a big city to purchase shoes.

Sears and Roebuck began as a watch and jewelry mail-order company in 1893. Rural areas at that time offered a limited variety of items at prices that varied according to the vendor’s inclination. The mail-order company expanded and became successful because it offered a wide selection of products at set, listed prices. In 1906, Sears went public and was the fi rst major retail IPO in American fi nancial history. In the three decades between 1925 and 1955, Sears expanded into brick-and-mortar stores and the sales from those stores eventually exceeded the mail-order revenue. In 1993, Sears discontinued its catalog. The company continued to expand and its profi ts peaked at $1.5 billion in 2006. However, just four years later, their profi ts plummeted to virtually nothing.

The irony here is that in 1994, just one year after Sears discontinued its catalog business, Jeff Bezos incorporated the company that would eventually be known as Amazon. The mail-order business that had been abandoned by Sears was reinvented and became the online immediate-gratifi cation machine and the e-commerce gargantua that it is today.

And now for my confession: I love to shop online. It is easy and convenient. I can compare prices before buying. I can shop at any hour and free shipping and easy returns make me a loyal customer.

The Dentists Service Company is striving to recreate that experience for our CDA members when we order dental supplies through the TDSC Marketplace. The Marketplace was established to provide CDA members with the same advantage that large group practices enjoy in securing favorable pricing. The price-negotiating power of CDA’s 27,000 members can translate into reductions in overhead and overall cost of providing patient care.

For the Marketplace to succeed and support our members, CDA members need to support the Marketplace by using it to buy supplies. This sounds easy. The pricing is very good and the shipping is free. If they do not have the item you are looking for, they will try to source it for you so it will be available in the future. They are eager for your feedback and will adapt to your needs and suggestions. It is easy to reach a human to speak to for customer support and they strive for excellence in every customer interaction. But I want to advise you of one hurdle that you must overcome.

When I talk with colleagues about the Marketplace, they “get it” right away. They understand how it can help their practices and they want to support an endeavor designed by CDA to benefi t CDA members. They sign in and take a look at the site. They see the advantageous pricing and they are sold. Then comes the hurdle: Usually, the dentist is not the team member who does the ordering.

The staff member who does the ordering will have to change the way she or he has ordered for years. This can be diffi cult. There are issues of friendship, trust, loyalty, ease and familiarity. They may have had the same dental supply representative for years. It can feel like a betrayal of a friend. Also, in some offi ces the dental supply rep does the inventory and restocking, thereby saving the staff member the physical effort. But though this cooperation on the part of the rep may seem like it is free, we all know the cost is part of the calculus that determines the supply prices. Sometimes the supply ordering may be the job of a staff member who does not feel comfortable with the computer. This can make it hard to switch over to the online site. Therefore, it may be necessary to assign the job to another more computer-savvy member of the offi ce team. Sometimes the hard job of changing gets in the way.

In my offi ce, I was very excited about the Marketplace. I introduced my staff to it and said, “This is where we want to place our orders.” I checked in a few days later and asked, “Did you order this from TDSC?” The answer was no. I explained again that we wanted to support TDSC and place our orders there. I checked again a few days later and found they were still using the familiar suppliers. So I had to crack down and say, “From now on, you must fi rst check the price of the item we need on the Marketplace site and if it is lower, order it there.”

The TDSC Marketplace and YouKerry K. Carney, DDS, CDE

For the Marketplace to succeed and support our members, CDA members need to support the Marketplace by using it to buy supplies.


210 A P R I L 2 01 8

A P R I L 2 0 1 8 E D I T O R

Finally, because my staff loves to fl aunt a retail bargain, they started coming to me to brag about how much money they had saved by ordering a certain item through TDSC. When they fi nally became familiar with the process, they were sold. They now have their favorite customer service representatives at TDSC. They know them by name. They do not hesitate to tell TDSC reps what our offi ce needs. If a product is not yet available through the Marketplace, our customer service rep will add it to their acquisition list and let us know when it becomes available. My

The Journal welcomes lettersWe reserve the right to edit all communica-

tions. Letters should discuss an item published in the Journal within the last two months or matters of general interest to our readership. Letters must be no more than 500 words and cite no more than fi ve references. No illustra-tions will be accepted. Letters should be submitted at editorialmanager.com/jcaldentas-soc. By sending the letter, the author certifi es that neither the letter nor one with substantially similar content under the writer’s authorship has been published or is being considered for publication elsewhere, and the author acknowl-edges and agrees that the letter and all rights with regard to the letter become the property of CDA.

staff members investigate the site specials and popular alternatives to the items we usually order and take great pleasure in racking up the savings.

Your role in the success of TDSC is as clear as Newton’s First Law of Motion. A body at rest will remain at rest unless acted upon by an external force. Each of us needs to be that external force. We need to give our staff members that little persistent push to make sure that we support TDSC’s group buying site, the Marketplace. The more successful TDSC is, the more TDSC can help us succeed. ■

GET REWARDED THREE WAYS.

SHAREMEMBER BENEFITS.

Offer subject to change. See official guidelines at cda.org/mgm. 1 Rewards issued to referring member once referral joins and pays required dues. Total rewards possible per calendar year are limited to $500 in gift cards from ADA and $500 in value from CDA. 2 Rewards issued to referring member once referral joins, pays required dues and spends $250+ in the TDSC Marketplace by December 31, 2018.

THE MORE NEW MEMBERS YOU REFER, THE MORE REWARDS!

Get started at cda.org/mgm.

THERE’S NO BETTER TIME for a member to get a new member. Our newest benefit? Group purchasing savings on dental supplies through the TDSC Marketplace.

1. RECEIVE A $100 AMERICAN EXPRESS® GIFT CARD from ADA.1

2. RECEIVE $100 TO SHOP THE TDSC MARKETPLACE from CDA.1

3. RECEIVE $50 MORE to shop the Marketplace if the new member places Marketplace orders totaling $250.2

Refer your colleagues and be rewarded.

®

Lee Skarin & Associates have been successfully assisting Sellers and Buyers of Dental Practices for nearly 30 years in providing the answers to these and other questions that have been of concern to Dentists.

Call at anytime for a no obligation response to any or all of your questionsVisit our website for current listings: www.LeeSkarinandAssociates.com

QUESTIONS MOST OFTEN ASKED BY SELLERS:1. Can I get all cash for the sale of my practice?

2. If I decide to assist the Buyer with financing, how can I be guaranteed payment of the balance of the sales price?

3. Can I sell my practice and continue to work on a part time basis?

4. How can I most successfully transfer my patients to the new dentist?

5. What if I have some reservation about a prospective Buyer of my practice?

6. How can I be certain my Broker will demonstrate absolute discretion in handling the transaction in all aspects, including dealing with personnel and patients?

7. What are the tax and legal ramifications when a dental practice is sold?

QUESTIONS MOST OFTEN ASKED BY BUYERS:1. Can I afford to buy a dental practice?

2. Can I afford not to buy a dental practice?

3. What are ALL of the benefits of owning a practice?

4. What kinds of assets will help me qualify for financing the purchase of a practice?

5. Is it possible to purchase a practice without a personal cash investment?

6. What kinds of things should a Buyer consider when evaluating a practice?

7. What are the tax consequences for the Buyer when purchasing a practice?

805.777.7707 818.991.6552 800.752.7461

CA DRE #00863149

LEE S

KARI

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ASSO

CIAT

ES IN

C.


A P R I L 2 0 1 8 213

Your readers may be fascinated by a set of experiments recently described by Rella Christensen, RDH, PhD, and her colleagues

at Technologies in Restoratives and Caries (TRAC) Research in a study published in Clinicians Report. They have shown beyond a reasonable doubt that living bacteria reside under all manner of treated carious lesions.

For a couple of years, TRAC Research has documented numerous vital microbes under fi llings. They harvested loads of bugs after fresh cavity preparation performed with the most aseptic techniques. Now they announce the same following treatment with silver diamine fl uoride (SDF). These results pry open a question that would be easier for us dentists to ignore: What are our treatments actually doing?

Dr. Christensen and colleagues went to extraordinary means to confi dently reach their conclusions. During my

Bacteria Live Under Treated Caries

recent visit to TRAC Research, I was spellbound by the measures they took. Dr. Christensen and her colleague Brad Ploeger generously showed me their clinical laboratory and walked me through each excruciating step. This was the most careful microbiological study I have ever seen — and coming from someone in a world-class infectious disease lab at the University of California, San Francisco, that means something.

Through physical isolation, decontamination, upward negative pressure and putting the microbiology workstations at the foot of the dental chair, they made possible the cultivation and quantifi cation of live bacteria from microgram samples taken in progressive excavations — each from one turn of a new quarter-round bur. Moreover, they identifi ed each isolate genetically. Each tooth contained its own positive and negative control. All studied lesions they showed me had several completely

sterile samples at the very end, after the thousands of bacteria in each step prior.

Dr. Christensen’s study shows that there is work left to do. For now, if no treatment of caries actually arrests all bacterial growth (neither Gordon J. Christensen-quality fi llings or SDF), then what do our treatments actually accomplish? The caring dentist would hope that operative or topical approaches debulk the bacterial infection of a carious lesion and limit access to nutrients for the remaining microbes, such that bacterial growth and therefore the progression of lesions is slowed so much that it would rarely be clinically relevant. Until we have more effective treatments, it seems that all dentistry may rely upon a race against time, for the tooth to exfoliate or the patient to pass before the bacteria overcome the pulpal defenses.

J E R E MY H O R S T , D D S , P H D

Postdoctoral FellowUCSF DeRisi Lab

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A P R I L 2 0 1 8 215

Impressions

Alt-LogicDavid W. Chambers, EdM, MBA, PhD

Frankly, I have had enough of alt-truths. In the end, the facts are not determinative: It is the interpretation that counts. Most of us know where to get the facts we want, conveniently packaged in our favorite interpretations. And as for the other guy’s supposed facts, here are some convenient defenses: “It might be premature to comment,” “probability is not certainty,” “the sample size is too small” and “beware of overgeneralizing.”

Information is a combination of the facts and the assumptions we make about what they would mean for us if true. When we witness a car accident or get an exposure, we say “Oh, no.” It is instinct to deny unwanted facts. The evaluation is instantaneous as though we were shielding ourselves from something we do not acknowledge as the case.

If we don’t like the facts, we can make adjustments for the source. It is easy enough to say the radiograph is not diagnostic. Insurance will not cover this. Dentists do not choose a staff member or associate exclusively on the information about the candidate or they would all be after the same ones. Dentists typically diagnose the condition of a tooth by combining what they see with their years of clinical wisdom regarding “these kinds of teeth.” It is human nature to combine real, particular data with information about cases of a general nature. The sophisticated name for this is evidence-based dentistry.

The critical question is how much weight should be placed on the facts and how much on generalizations about where the facts came from and what they mean. Typically, decisions that are based on an honest combination of facts and their sources are better than decisions that undervalue either. There are formal techniques for this.

So it may be correct to say “beware of generalizations,” but it is incorrect to say we can get rid of them. Better by far to say “be aware of generalizations.” It is unethical to use logic that misleads others by protecting our generalizations at the expense of inconvenient facts. What makes this an ethical matter is picking only the facts we want or distorting them to match our generalizations. The patient who declines the obvious best health options does so either because he or she has not been given full informed consent or because the common facts are placed in different contexts. Change the context rather than the facts. A colleague who engages in what you may consider to be questionable treatment may have diagnosed the case exactly as you have. What is needed before judgment is comparing the contexts. ■

The nub:

1. All facts are alt-facts; it is the interpretation that matters.

2. If dentistry were reducible to objective reality, staff or computers would replace dentists.

3. Agreement with others is a matter of perspective; unless we can see as others do, we are pretty certain to disagree.

David W. Chambers, EdM, MBA, PhD, is a professor of dental education at the University of the Pacifi c, Arthur A. Dugoni School of Dentistry, San Francisco, and the editor of the American College of Dentists.


216 A P R I L 2 01 8

Hot Tea, Smoking and Alcohol: A Cancer CocktailDrinking hot tea, when combined with heavy alcohol and tobacco use,

increases the risk of esophageal cancer by fivefold, according to a China-based study published recently in the journal Annals of Internal Medicine.

The study followed tea-drinking habits of more than 450,000 people aged 30 to 79 over the course of about nine years. Researchers asked participants about their tea-drinking habits, along with other lifestyle choices, through a questionnaire.

Research findings suggest that those who reported drinking hot or burning-hot tea regularly in addition to excessively drinking alcohol or smoking (two already known causes of cancer) increased their chances of developing esophageal cancer. Excessive drinking was defined as having 15 grams of pure alcohol (slightly more than a 12-ounce glass of beer or 5-ounce glass of wine) every day.

Researchers noted that more studies are needed to confirm these findings and tea’s possible link to cancer.

In response to the study, the Tea Association of the USA released a statement pointing to the health benefits of tea, including research suggesting it could actually prevent cancer, and stating that “alcohol and tobacco appear to remain risk factors for esophageal cancer.”

The International Agency for Research on Cancer (IARC), which is part of the World Health Organization, and the National Toxicology Program do not recognize tea as a carcinogen. But the IARC did find that hot beverages (at least 149 degrees) “probably” cause cancer of the esophagus.

Learn more about this study in the Annals of Internal Medicine (2018); doi: 10.7326/M17-2000.

A P R I L 2 0 1 8 I M P R E S S I O N S

by an enzyme that processes lipids into the starting material to make infl ammation-enhancing molecules. So the Bacteroidetes lipids have a double whammy on the blood vessels: The immune system sees them as a signal of bacterial invasion and then enzymes break them down and super-charge the infl ammation. Usually the Bacteroidetes bacteria stay in the mouth and gastrointestinal tract. If conditions are right, they can cause gum disease in the mouth but not infect the blood vessels.

The next step in the research is to analyze thin slices of atheroma to localize where the bacterial lipids are accumulating. If they are found within the atheroma but not in the normal artery wall, that would be convincing evidence that these lipids are associated specifi cally with atheroma formation and therefore contribute to heart disease.

Learn more about this study in the Journal of Lipid Research (2017); doi: 10.1194/jlr.M077792.

Bacterial Fats Not Dietary Fats May Cause Heart Disease

New evidence suggests that fatty molecules might come not only from eating fatty, cholesterol-rich food but from bacteria in the mouth, which may explain why gum disease is associated with heart trouble, according to a report in the Journal of Lipid Research.

For decades, doctors and researchers assumed that the lipids that can lead to heart attacks and strokes came from eating fatty food. But the research hasn’t borne this out. Some people who eat large amounts of fatty food don’t necessarily develop heart disease.

However, University of Connecticut researchers believe they may have solved part of this puzzle. Using careful chemical analysis of atheromas — growths that form in the walls of blood vessels — collected from patients, they found lipids with a chemical signature unlike those from animals. Instead, these strange lipids come from a specifi c family of bacteria called Bacteroides, which make distinctive fats.

The chemical differences between bacterial and human lipids result in subtle weight differences between the molecules, which might be the reason they cause disease, according to the study. The immune cells that initially stick to the blood vessel walls and collect the lipids recognize them as foreign, react to the lipids and set off alarm bells.

The research team showed that the Bacteroidetes lipids could be broken down


A P R I L 2 0 1 8 217

Squamous cell carcinoma of the tongue is an aggressive form of cancer that generally affects older people. Patients with the disease often fi nd it diffi cult to eat, swallow food or speak. Reasons for its generally poor prognosis include late detection.

But a new study published in the journal Oncotarget found that bacterial diversity and richness and fungal richness

are signifi cantly reduced in tumor tissue compared to their matched nontumor tissues. This raises the prospect that certain bacteria and fungi, in suffi cient amounts and in possibly interactive ways, may play a part in the development of oral tongue cancer, according to the study conducted by a team of researchers from the Case Western Reserve University School of Medicine, the

Cleveland Clinic and the University Hospitals Cleveland Medical Center.

While the bacteriome is increasingly recognized as playing an active role in health, the role of the mycobiome has never before been studied in the case of oral tongue cancer. In the new study, the researchers extracted tissue DNA from 39 paired tumor and adjacent normal tissues from patients with the cancer. Analyses showed that Firmicutes was the most abundant bacterial phylum and was signifi cantly increased in tumors compared to nontumor tissue (48 percent versus 40 percent, respectively). In total, the abundance of 22 bacterial and seven fungal genera types was signifi cantly different between the tumor and adjacent normal tissue, includingStreptococcus, which was signifi cantly increased in the tumor group (34 percent versus 22 percent in normal tissue.)

“Our fi ndings mean that it may be possible to perform precautionary testing in patients at high risk for oral tongue cancer,” said the study’s co-senior author Mahmoud A. Ghannoum, PhD, professor at the Case Western Reserve School of Medicine and the University Hospitals Cleveland Medical Center. “If the patterns that we found are present in people who are not yet showing signs of lesions, we could begin treatment early, offering the possibility of better patient outcomes.”

Researchers say additional research is needed to understand how these two communities infl uence or are infl uenced in disease settings such as oral tongue cancer.

Learn more about this study in Oncotarget (2017); doi.org/10.18632/oncotarget.21921.

Research Finds Markers for Early Diagnosis of Tongue Cancer

Tooth Enamel Determines Sex of Human RemainsA new method for determining the sex of human remains using tooth

enamel has been discovered by researchers in the United Kingdom and Brazil, according to a study published in the journal Proceedings of the National Academy of Science in December 2017.

Determining the sex of human remains has applications in archaeological and legal contexts, among others. DNA sequencing can be used for sex determination, but the approach is often expensive, time-consuming and depends on the quality of the DNA sample. In the study, researchers used peptides from tooth enamel, a durable human body tissue, to develop a method for determining the sex of human remains.

To extract peptides from tooth enamel, the method uses a minimally destructive acid-etch procedure. Sex chromosome-linked isoforms of amelogenin

— an enamel-forming protein — are identified from the acid-etch sample using nanoflow liquid chromatography mass spectrometry, according to the study.

The authors tested the method on the remains of seven adult individuals from the late 19th century as well as male and female pairs from three archaeological sites ranging from 5,700 years ago to the 16th century in the United Kingdom. In each context, the method successfully determined the sex of the individuals, as confirmed by comparison with coffin plates or standard osteological analyses. According to the authors, the method might help improve techniques for sex determination of human remains with potential applications in bioarcheology and medical-legal science.

Read more of this study in the Proceedings of the National Academy of Science (2017); doi: 10.1073/pnas.1714926115.

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218 A P R I L 2 01 8

that water fl ow exerts shear stress to remove the biofi lm. In addition to this shear effect, the cavitating jet also produces a considerable force when the bubbles collapse that is able to remove particles from the biofi lm and carry them away. The researchers suggest that the two processes probably work in synergy to make the cavitating jet superior to the water jet.

Read more of this study in Implant Dentistry (2017); doi: 10.1097/ID.0000000000000681.

between the amounts of dental plaque removed by both methods after one minute of cleaning, that changed after longer exposure. After three minutes, the cavitating jet had removed about a third more plaque than the water jet did, leaving little plaque stuck to the implant at the end of the experiment. The cavitating jet was also able to remove the plaque not only from the root section of the screws, but also from the harder-to-reach crest section.

Previous research has shown

A P R I L 2 0 1 8 I M P R E S S I O N S

Blasting Dental Plaque With Microbubbles

A research team from Tohoku University and Showa University in Japan discovered that using a cavitating jet to clean dental implants was more effi cient and thorough than a water jet, which has been used for a long time to remove plaque from dental implants to keep them clean, according to a study published in the journal Implant Dentistry. A cavitating jet uses a nozzle to inject high-speed fl uid through water to create very tiny bubbles of vapor. When these bubbles collapse, they produce strong shockwaves that are able to remove contaminants.

Researchers conducted the study to look for better ways for dentists to remove the plaque that builds up on the screws that hold dental implants in place. While the plaque sticks mainly to the crown, it also adheres to the microgrooves of the exposed parts of the screws and are much harder to clean.

To compare the cleaning effect of a cavitating jet to that of a water jet, the team grew a biofi lm within the mouths of four volunteers. After three days, they used the two different methods to clean the mouths, measuring the amount of plaque remaining at several time intervals.

While there was little difference

The researchers used a nozzle to create the cavitation bubbles that removed the plaque when they collapsed. (Credit: Hitoshi Soyama)

‘Smart’ Material Could Help Fight Tooth DecayA study conducted by the University of Toronto has resulted in a novel

way to minimize recurrent caries, according to research published recently in the journal Scientific Reports.

Researchers in the university’s department of materials science and engineering, faculty of dentistry and the Institute of Biomaterials and Biomedical Engineering tackled the issue and proposed a novel solution — a filling material with tiny particles made by self-assembly of antimicrobial drugs designed to stop bacteria in its tracks. The study shows that these particles may solve one of the biggest problems with antibacterial filling materials: How do you store enough drug within the material to be effective for someone’s entire life?

“Adding particles packed with antimicrobial drugs to a filling creates a line of defense against cavity-causing bacteria,” said Professor Ben Hatton, PhD. “But traditionally there’s only been enough drug to last a few weeks. Through this research we discovered a combination of drugs and silica glass that organize themselves on a molecule-by-molecule basis to maximize drug density with enough supply to last years.” This discovery means the team can pack 50 times as much of the bacteria-fighting drugs into the particles.

“We know very well that bacteria specifically attack the margins between fillings and the remaining tooth to create cavities,” said Professor Yoav Finer, DMD, PhD. “Giving these materials an antimicrobial supply that will last for years could greatly reduce this problem.”

The research team plans to test these drug-storing particles in dental fillings.

Read more of this study in Scientific Reports (2018); doi: 10.1038/s41598-018-19166-8.


A P R I L 2 0 1 8 219

The Scottish government recently launched a nationwide Oral Health Improvement Plan (OHIP) to provide a framework for improving the oral health of

“the next generation,” according to a news article on the website fl uoridealert.org.

As part of the OHIP, the government will introduce a system of monitoring to ensure that all dental practices provide

preventive treatment for children. This system will include oral health risk assessments (OHRA). Patients will be seen according to their OHRA results, meaning they may be recommended to visit the dentist once every 24 months.

The OHIR will also implement ways to meet the needs of Scotland’s aging population. The Scottish government predicts that the number of people aged

over 65 will increase by 53 percent by 2039 and has therefore decided to introduce arrangements to accredited general dental practitioners to provide care in elderly care homes. Additionally, dental practices will be required to display the government oral health information on self-care, treatments available, costs and services and to communicate this information clearly to patients.

In response to the 46 percent increase in the number of dentists working under Scotland’s national health system — from 2,474 in March 2007 to 3,613 in March 2017 — the OHIP will establish a dental workforce planning forum, which will make recommendations for workforce requirements, morale and issues affecting dental teams. Promotional programs will also be developed to encourage dentists to work in rural areas of Scotland, and a European Union (EU) dentists’ network will be established for after Brexit, providing an opportunity for dentists from the EU to engage with Scotland’s chief dental offi cer.

While the government admits OHIP is an ambitious program of work, it has pushed on to establish a number of short-term working groups to take it forward. In the meantime, a biannual newsletter will be produced to provide updates on the progress that is being made toward implementation and a number of

“roadshow” events will be held to discuss the implementation arrangements.

Read more about Scotland’s Oral Health Improvement Plan at fl uoridealert.org/news/30322.

Scotland Launches Oral Health Improvement Plan

Wine Polyphenols Could Benefi t Oral HealthAbundant and structurally diverse polyphenols have been attributed

to the healthy effects of wine on the colon and heart, but new research reported in the American Chemical Society’s Journal of Agricultural and Food Chemistry in February 2018 shows that wine polyphenols might also be good for oral health.

Polyphenols are antioxidants, meaning they likely protect the body from harm caused by free radicals. However, recent work indicates polyphenols might also promote health by actively interacting with bacteria in the gut. That makes sense because plants and fruits produce polyphenols to ward off infection by harmful bacteria and other pathogens, according to research.

M. Victoria Moreno-Arribasm, who studies wine chemistry, and research colleagues from the University of Madrid in Spain wanted to know whether wine and grape polyphenols would also protect teeth and gums, and if so, how this could work on a molecular level. The researchers checked out the effect of two red wine polyphenols, as well as commercially available grape seed and red wine extracts, on bacteria that stick to teeth and gums and cause dental plaque, cavities and periodontal disease.

Working with cells that model gum tissue, they found that the two wine polyphenols in isolation — caffeic and p-coumaric acids — were generally better than the total wine extracts at cutting back on the bacteria’s ability to stick to the cells. When combined with the Streptococcus dentisani, which is believed to be an oral probiotic, the polyphenols were even better at fending off the pathogenic bacteria. The researchers also showed that metabolites that formed when digestion of the polyphenols begin in the mouth might be responsible for some of these effects.

Learn more about this study in the Journal of Agricultural and Food Chemistry (2018); doi: 10.1021/acs.jafc.7b05466.


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i n t r o d u c t i o n

GUEST EDITOR

Leif K. Bakland, DDS, is a distinguished emeritus professor of endodontics at the Loma Linda University School of Dentistry. His professional career has been devoted to teaching, research and patient care. He is the author and co-author of more than 100 scientifi c abstracts, articles and book chapters and was co-editor with John Ingle, DDS, of the fourth, fi fth and sixth editions of Ingle’s Endodontics.Confl ict of Interest Disclosure: None reported.

Current evolving aspects of endodontic treatment are connected to many historical efforts to save and preserve teeth. An

oft-quoted recommendation in Miguel de Cervantes’ novel, Don Quixote, is still good advice 400 years later: “Because I’ll have you know, Sancho, that a mouth without teeth is like a mill without its stone, and you must value a tooth more than a diamond.”1

To appreciate the treatment advances that have been and continue to be made in patients with endodontic problems, one may look at the evolving understanding of the etiology and diagnosis of pulpal and periapical disease. That understanding has led to improvements in treatment outcomes making endodontic treatment a quite predictable treatment modality.2

This issue of the Journal contains reports on current advances in endodontic treatment procedures in four areas: Management of bacterial contamination in the root canal system; improvement in visualization of the tooth-bone complex through cone beam computed tomography; replacement of necrotic pulpal tissue in developing immature teeth; and enhanced understanding of the balance between endodontics and dental implants in a patient-centered environment.

Evolving Aspects of Endodontic TreatmentLeif K. Bakland, DDS

Root Canal DisinfectionThe pulp spaces in human teeth

are complex. That notion is not new — a century ago Hess3 examined 2,800 extracted teeth and described the anatomy of the root canal system; his images show pulp spaces with numerous variations in shapes and sizes. In recent years, the advent of microcomputed tomography (microCT) has allowed an even more detailed examination of the complexity of the root canal system4 (FIGURE 1). From such micro- CT images one can only wonder how root canal treatment can be done and how such treatment can succeed.

From the beginning of human history and through subsequent millennia until the last couple of centuries, dental pulp infections from caries and trauma have been major medical problems. Bacteria are for the most part prevented from penetrating through the skin and mucous membranes into underlying tissues. But when they gain access to the dental pulp, they can grow in a protected environment not accessible to the body’s defense system and stimulate infl ammatory reaction in tissues surrounding the tooth and even invade these tissues and the bloodstream. The result can be disastrous (FIGURE 2).


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Until modern times, the most common treatment for infected, painful teeth was usually extraction, often a crude and painful procedure. There were, however, according to Ingle et al.1 some innovative approaches to treatment based on the notion that “tooth worms” were responsible for the dental problems — an idea that fi rst seemed to have originated in China perhaps as long as two millennia ago. The Chinese then started applying arsenicals to carious lesions, a procedure that much later was also adopted in Europe and subsequently in the U.S.5

A more invasive approach was reported by Zias and Numeroff.6 They discovered, in a mass grave in the Negev Desert, a skeleton from 200 BCE with a maxillary lateral incisor that had a 2.5 mm bronze wire inserted in the root canal. Radiographically, the tooth apex was associated with a large bony lesion, likely of endodontic origin, and the wire was inserted in a way suggesting some learned skills on the part of the person performing this ancient root canal treatment (FIGURE 3).

More recent efforts to address pulpal disease probably began about 250 years ago when the father of modern dentistry, Pierre Fauchard, recommended removal

of diseased pulp tissue, a procedure that sometimes was accomplished by cauterization with red-hot wires.1 It is not known when the fi rst root canal fi lling was placed, but McQuillen7 reported seeing a patient who had a root-fi lled tooth that likely was treated in the early part of the 1800s. The root canal fi lling material apparently was gold foil. Later in the 19th century, further progress in endodontics saw the introduction of the rubber dam for dental procedures, root canal instruments, intracanal antiseptics, gutta-percha and local anesthesia.1

By the end of the 19th century, the technical aspects of cleaning, preparing and fi lling root canal spaces were aided by the innovations described. Of equal importance was the growing understanding of the biological basis for root canal treatment. Contributing to this understanding was the work done by Willoughby D. Miller, MD, DDS,

who had studied microbiology under Dr. Robert Koch (of Koch’s postulate fame) in Berlin. Dr. Miller laid the foundation for modern endodontics with the publication of his classic 1890 textbook Microorganisms of the Human Mouth.8 Thus, the technical and the biological concepts were coming together to help form a sound basis for saving teeth through root canal therapy.

Recognizing that bacteria play an important role in many diseases, including dental disease, researchers began to speculate that bacteria had a special selective affi nity for certain tissues and organs. That concept became the basis for the focal infection theory,9 which led to physicians blaming dental diseases for such diverse conditions as rheumatism, appendicitis and ulcers. Contributing to this concept was a seminal event in the history of dentistry that took place in 1910 when a physician

FIGURES 2. During excavation in 2005 at the Jamestown settlement near Williamsburg, Va., by the Jamestown Rediscovery and the Smithsonian Institution, the skeletal remains of a 15-year-old boy were exhumed. According to historical records, he died in an American Indian attack in 1607. Martin D. Levin, DMD, adjunct professor of endodontics at the University of Pennsylvania, and Barry Pass, BSc, MSc, DDS, PhD, professor of oral diagnosis and radiology at Howard University, assisted in the analysis of the traumatic fracture of the mandibular left central incisor in early childhood, leading to food impaction, bacterial infection of the pulp and extensive alveolar bone destruction. The skull of JR1225B showing a missing buccal plate and missing mandibular incisors (2A). The fractured margins of the mandibular buccal plate appear to fl are anteriorly and the lingual cortical plate is intact. The anterior mandible shows radiographic features consistent with buccal and lingual expansion with a large area of bone destruction. An intraoral radiographic image of the mandibular left central incisor showing an immature tooth with a complicated crown fracture with pulp exposure (2B). The canal contained cotton fi bers indicating that an eff ort had been made to prevent food impaction. (Courtesy Martin D. Levin, DMD, Washington, D.C.)

FIGURE 1. MicroCT of a maxillary molar showing the complex anatomy of the root canal system. (Courtesy Gina D. Roque-Torres, DDS, PhD, MSD, Center for Dental Research at the Loma Linda University School of Dentistry)

FIGURE 2A . FIGURE 2B .


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from the United Kingdom, Dr. William Hunter, gave a stirring speech at McGill’s University in Montreal entitled “The role of sepsis and antisepsis in medicine.”10 Dr. Hunter had observed in the U.K. a dismal state of dental health in the population at large — patients with rampant caries and periodontal disease, a condition he called “oral sepsis.” What made it worse was that in many cases patients had gold crowns and bridges sitting on top of rotting teeth. Incidentally, in Europe this type of dentistry — that is gold crowns and bridges — was often called “American dentistry”! His description was graphic as he painted a picture of gold crowns as “… mausoleums of gold over a mass of sepsis.”11

Dr. Hunter’s speech contributed to the notion that foci of infection could disseminate bacteria to tissues and organs all over the body. It apparently made sense in the medical community,

thus leading to what Dr. Louis I. Grossman12 later described as a national furor that resulted in people running to their physicians to inquire whether illnesses they had were the result of bad teeth and then to their dentists to have the teeth taken out. Dr. Grossman summarized the problem by observing: “The focal infection theory that created dissensions among dentists, and between dentists and physicians, was destined to die a slow, reluctant death, but leaving many people edentulous.” There were, however, many pioneers in endodontics, including Dr. Grossman, who were able to demonstrate that endodontic treatment was safe and valid.12 Sadly, the false concept of focal infection appears occasionally even in modern times.13

While concerns about focal infection are not the driving force, eliminating bacteria from the root canal system has been a goal for a long time. Many approaches, from disinfectants and irrigants to ultrasonic stimulation, have been tested and new innovations are on the horizon. In this issue, author Markus Haapasalo, DDS, PhD, discusses the current status of irrigation effectiveness and progress.

Pulp Space VisualizationMedical radiology was introduced

in the 1890s on both the European and the American continents. In 1895 in Germany, Dr. Wilhelm Conrad Röntgen (FIGURE 4) discovered what he termed X-rays. At the same time in the U.S., Nikola Tesla and Thomas A. Edison made the same discovery and adopted Dr. Röntgen’s term for the cathode rays.14 German dentist Friedrich Otto von Walkhoff made the fi rst dental image with X-rays shortly thereafter.15 In the U.S., Morton16 was probably the fi rst to describe its use in dentistry, when in 1896 he addressed the New York Odontological Society and demonstrated radiographs of teeth. Interestingly, he also noted “that the pulp-chamber is beautifully outlined …”

Being able to visualize the root canal system became an important modality in the treatment of teeth with pulpal problems. The fi rst dentist to use radiography for root canal therapy was Dr. C. Edmund Kells in New Orleans in 1899.17 The obvious benefi ts included the ability to visualize the canals and to monitor treatment outcomes (FIGURES 5).

Advances in radiographic equipment and X-ray fi lms proceeded over the following decades with the next major progress being the development of digital radiography.18 Again, endodontic treatment benefi tted from this technical advance with the ability to get instant imaging of a tooth and convenient enhancement of the image quality.

The latest development in dental imaging is the application of cone beam computed tomography (CBCT). Endodontists were quick to recognize the benefi ts of three-dimensional imaging and have adopted its use extensively.19,20 The increasing role of CBCT in endodontic treatment is explored by author Robert S. Roda, DDS, MS, in this issue.

FIGURE 3 . Oldest known root canal fi lling. Radiograph of a maxillary lateral incisor from skeletal remains in an excavation site in the Negev Desert from about 200 BCE. A bronze wire was implanted in the root canal perhaps to prevent food impaction. (Used with permission Ingle et al. ENDODONTICS, 5th ed. BC Decker, 2002, Chapter 1, fi gure 1. First published: Zias J, Numeroff K. Operative dentistry in the second century BCE. J Am Dent Assoc 1987; 114:665–6.)

FIGURE 4 . Dr. Wilhelm Conrad Röntgen, 1845–1923. (www.nobelprize.org/nobel_prizes/physics/laureates/1901/rontgen-bio.html)


224 A P R I L 2 01 8

Treatment Options for Diseased PulpsThe specialty of endodontics is

involved with the physiology and pathology of the dental pulp.21 Historically that meant recognizing pulps that were diseased and needed to be removed and replaced with a fi lling material such as silver points or gutta-percha. Preserving pulp tissue, however, was promoted by some dentists; the fi rst to recommend that idea was probably Dr. B.W. Hermann22 nearly a century ago when he published his report on the use of calcium hydroxide (CH). Dr. Grossman15 paid tribute to Dr. Hermann by pointing out that his purpose for suggesting CH as a medicament was “not to destroy but to heal the pulp.”

In subsequent decades, CH became a much relied-upon medicament for treatment of the pulp.23–25 For the most part, however, treatment with CH was confi ned to immature, developing teeth with traumatic crown fractures; the procedure became knowns as a Cvek-type pulpotomy. It was rarely used in teeth with carious pulp exposures.26 The expected response to exposing pulp tissue to CH was development of a hard tissue barrier (dentin bridge) to protect the underlying pulp tissue. One of the problems with the use of CH in these cases is that CH gradually neutralizes and loses its ability to kill bacteria. If microleakage of the coronal restorations occurs, bacteria may then penetrate through the CH-generated dentin bridge through which they can cause pulpal disease.27

A new era in pulp treatment began when the fi rst bioceramic material, mineral trioxide aggregate (MTA), was shown to be useful for pulp capping in traumatically exposed teeth.28 It was subsequently shown that it could also be successfully used in teeth with carious pulp exposures29 (FIGURES 6). Further, a recent study showed MTA to be more predictable than CH in treatment of teeth with carious exposures.30 Preserving vital pulps has now become an important component of general dentistry as well as pediatric dentistry and endodontics.31

A new era of pulp therapy arrived with the clinical report published in 2001 by Iwaya et al.32 They demonstrated that teeth with dens evaginatus could be treated in a way that would preserve uninfected pulp tissue in the root canal and permit continued root formation. Dens evaginatus is an anomaly of odontogenesis in which a central cusp develops on the occlusal surface of a crown, and during eruption, when contact is made with the opposing tooth, the cusp can fracture and expose the underlying pulp providing a pathway for bacteria to enter.33 In the case presented by Iwaya et al.,32 the bacteria had stimulated a periapical response resulting in an apical abscess. The authors decided to attempt to preserve as much pulpal tissue as possible and limited the treatment to removal of infected tissue

and allowing a blood clot to form in the space where the infected pulp tissue had been removed. They sealed the occlusal access and monitored the outcome, which was continued root formation along with healing of the apical abscess.

The Iwaya report generated an immense interest among endodontists. Could diseased pulp tissue be replaced with new pulp tissue — pulp regeneration? While that question stimulated case reports, professional lectures and research projects, it is reasonable to conclude that at this time “pulp regeneration” is not clinically feasible.34,35 But techniques for managing teeth in young patients to allow continued root development continue to be developed. Author Paul V. Abbott, BDS, MDS, discusses the topic in this issue.

Endodontics and Dental ImplantsDental implants have a long

history. The ancient Mayans apparently successfully placed dental implants.36 In 1913, Dr. E.J. Greenfi eld from Kansas presented a lecture on the “… implantation of artifi cial roots …” made from irridio-platinum to which crowns could be attached.37 But it was not until the 1970s that root-formed implants, as developed by Per-Ingvar Brånemark in Sweden, again appeared.38 During the preceding years, other types of implants, such as the blade and the subperiosteal implants, had gained prominence.39


FIGURES 5. Root canal treatment by Dr. G. Mitchell in 1920. Preoperative fi lm (5A). Completed treatment — note chloroform softened gutta-percha extending past apical foramen. This was done on purpose to allow for shrinkage of the softened gutta-percha (5B). Two-year follow-up (5C). Nearly complete bony healing and absorption of the excess fi lling material. Note that the complexity of the root canal system could be readily visualized radiographically.

FIGURE 5A . FIGURE 5B . FIGURE 5C .


A P R I L 2 0 1 8 225

Endodontists became interested in endodontic endosseous implants when Orlay40 suggested their use in splinting mobile teeth with periodontal disease. Frank41 soon after reported on six cases in which endodontic implants were used to stabilize teeth with poor crown-

root ratios. For a while the procedure gained some popularity and reported success39,42 (FIGURE 7). But reports on implant corrosion43,44 probably contributed to a reduced interest in endodontic implants over time.

As Brånemark’s root-formed implants gained in popularity, endodontists began to worry that placement of dental implants would obviate the choice of endodontic treatment for teeth with pulpal disease. But clinical data began to accumulate showing that endodontically treated teeth held up well in comparison with implants45,46 with the added advantage of delaying the need for replacing a tooth. A pertinent question was asked by Giannobile and Lang47 in a recent editorial, “Are dental implants a panacea or should we better strive to save teeth?”

Recognizing the value of dental implants when indicated, endodontists also began placing them.48,49 In this issue, authors Tory Silvestrin, DDS, MSD, and Charles J. Goodacre, DDS, MSD, report on the coexistence of endodontics and implant dentistry.

Root canal therapy has evolved over the past two centuries to where treatment outcomes are highly favorable.2 In this issue, we describe evolving aspects of endodontic treatment that may further promote efforts to preserve natural dentition. ■

REFERENCES

1. Ingle JI, Bakland LK, Beveridge EE, Glick DH, Hoskinson AE. Modern endodontic therapy. In Ingle’s ENDODONTICS, Ingle JI, Bakland LK, eds. 5th ed. Chapter 1, BC Decker, Hamilton, Canada, 2002.2. Friedman S. Endodontic treatment outcome: The potential for healing and retained function. In Ingle’s ENDODONTICS 6th ed. Ingle JI, Bakland LK, Baumgartner JC, eds. Chapter 32. BC Decker Inc. Hamilton, 2008.3. Hess W. Formation of root-canals in human teeth. J National Dent Assoc 1921;8:704–34.4. Cleghorn BM, Goodacre CJ, Christie WH. Morphology of teeth and their root canal systems. In Ingle’s ENDODONTICS 6th ed, Ingle JI, Bakland LK, Baumgartner JC, eds. Chapter 6. BC Decker Inc. Hamilton, 2008.5. White JD. Sensitive dentin — arsenic, and the treatment of the dental pulp. Editorial. The Dental Cosmos 1864;6:27–8.6. Zias J, Numeroff K. Operative dentistry in the second century BCE. J Am Dent Assoc 1987;114:665-6.7. McQuillen JR. Editorial. Who fi lled the fi rst nerve cavities? The Dental Cosmos 1862;3:556–7.8. Miller WD. The microorganisms of the human mouth. The S. S. White Dental Mfg. Co. Philadelphia, 1890.9. Rosenow EC. The relation of dental infection to systemic disease. The Dental Cosmos 1917;59:485–91.10. Hunter W. The role of sepsis and antisepsis in medicine and the importance of oral sepsis as its chief cause. Dent Register 1911;44:579–611.11. Hunter W. The role of sepsis and antisepsis in medicine. The Dental Cosmos 1918;60:585–602.12. Grossman LI. Focal infection: Are oral foci of infection related to systemic disease? Dent Clin North Am 1960;4:749–63.13. Pallasch TJ, Wahl MJ. Focal infection: new age or ancient history? Endod Topics 2003;4:32–45.14. Abramovitch K. The 120th anniversary of the discovery of X radiation and dental radiology. LLUSD Articulator 2016;27:38–44.15. Grossman LI. Pioneers in endodontics. J Endod 1987;13:409–15.16. Morton WJ. The X-ray and its application in dentistry. The Dental Cosmos 1896;38:478–86.17. Langland OE, Langlais RP. Early pioneers of oral and maxillofacial radiology. Oral Surg Oral Med Oral Pathol Oral

FIGURE 6A .

FIGURE 6C . FIGURE 6D.

FIGURE 6B .

FIGURES 6. Vital pulp therapy with bioceramic cement (MTA). The patient responded normally to cold test. Radiograph of a fi rst mandibular molar with deep distal caries (6A). Caries excavation resulted in two pulp exposures (6B). Sodium hypochlorite on a cotton pellet was used for hemostasis. Postoperative radiograph MTA covering the pulp exposers; the MTA was covered with a temporary fi lling, which subsequently was replaced with a bonded composite resin fi lling (6C). Control radiograph taken eight years later. The tooth was comfortable, responded to pulp tests and no radiographic lesions were noted (6D). (Courtesy George Bogen, DDS, Los Angeles)

FIGURE 7. Endodontic endosseous implant providing stabilization of maxillary lateral incisor for 32 years. (Courtesy Dr. Pabla Barrientos, Santiago, Chile)


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Radiol Endod 1995;80:496–511.18. Farman AG, Ramamurthy R, Hollender LG. Digital imaging for endodontics. In Ingle’s ENDODONTICS 6 ed, Ingle JI, Bakland LK, Baumgartner JC, eds. Chapter 15B. BC Decker Inc. Hamilton, 2008.19. Fayad MI. Contemporary endodontic technology: Cone beam imaging in treatment planning. AAE Communiqué, January 2014, pp 3–7.20. Setzer FC, Hinckley N, Kohli MR, Karabucak B. A survey of cone-beam computed tomographic use among endodontic practitioners in the United States. J Endod 2017;43:699–704.21. Gutmann JL. History of endodontics. In Ingle’s ENDODONTICS 6th ed. Ingle JI, Bakland LK, Baumgartner JC, eds. Chapter 2. BC Decker Inc. Hamilton, 2008.22. Dammaschke T. The history of direct pulp capping. J Hist Dent 2008;56:9–23.23. Berk H. The eff ect of calcium hydroxide methyl cellulose paste on the dental pulp. J Dent Child 1950;17:65–8.24. Cox CF, Bergenholtz G, Heys DR, Syed SA, Fitzgerald M, Heys RJ. Pulp capping of the dental pulp mechanically exposed to oral microfl ora: A one to two year observation of wound healing in the monkey. J Oral Path 1985;14:156–68.

25. Cvek M. A clinical report on partial pulpotomy and capping with calcium hydroxide in permanent incisors with complicated crown fracture. J Endod 1978;4:232–7.26. Cvek M. Partial pulpotomy in crown-fractured incisors — results three to 15 years after treatment. Acta Stomatologica Croatica 1993;27:167–73.27. Bakland LK, Andreasen JO. Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma? A review. Dent Traumatol 2012;28:25–32.28. Pitt Ford TR, Torabinejad M, Abedi HR, Bakland LK. Using mineral trioxide aggregate as a pulp-capping material. J Am Dent Assoc 1996;127:1491–4.29. Bogen G, Kim JS, Bakland LK. Direct pulp capping with mineral trioxide aggregate. An observational study. J Am Dent Assoc 2008;139:305–15.30. Kundzina R, Stangvaltaite L, Eriksen HM, Kerosuo E. Capping carious exposures in adults: A randomized controlled trial investigating MTA versus calcium hydroxide. Int Endod J 2016; doi: 10.1111/iej.12719.31. Bakland LK, Andreasen JO. Biological considerations in the management of traumatic dental injuries. Endod Topics

2014;30:440–50.32. Iwaya S, Ikawa M, Kubota M. Revascularization of an immature permanent tooth with apical periodontitis and a sinus tract. Dent Traumatol 2001;17:185–7.33. Geist JR. Dens evaginatus. Oral Surg Oral Med Oral Oral Pathol Oral Radiol Endod 1989;67:628–631.34. Andreasen JO, Bakland LK. Pulp regeneration after non-infected and infected necrosis, what type of tissue do we want? A review. Dent Traumatol 2012;28:13–18.35. Huang GT, Garcia-Godoy F. Missing concepts in de novo pulp regeneration. J Dent Res 2014;93:717–224.36. Ring ME. Dentistry: An Illustrated History. The CV Mosby Company, St. Louis, 1985, p 17.37. Greenfi eld EJ. Implantation of artifi cial crown and bridge abutments. The Dental Cosmos 1913;55:364–9.38. Adell R, Lekholm U, Rockler B, Brånemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;10:387–416.39. Lozada JL, Kleinman A. Osseointegrated dental implants. In Ingle’s ENDODONTICS 6th ed. Ingle JI, Bakland LK, Baumgartner JC, eds. Chapter 33. BC Decker Inc. Hamilton, 2008.40. Orlay HG. Endodontic splinting treatment in periodontal disease. Br Dent J 1960;108:118–21.41. Frank AL. Improvement in the crown-root ratio by endodontic endosseous implants. J Am Dent Assoc 1967;74:451–62.42. Wolff J, Sándor GK, Forouzanfar T, Schulten EAJM, Oikarinen KS. A 22-year follow-up of an endodontic implant. Dent Traumatol 2015;31:409–12.43. Seltzer S, Maggio J, Wollard R, Green D. Titanium endodontic implants: A scanning electron microscope, electron microprobe, and histologic investigation. J Endod 1976;2:267–76.44. Simon JH and Frank AL. The endodontic stabilizer: Additional histologic evaluation. J Endod 1980;6:450–5.45. Holm-Pedersen P, Lang NP, Müller F. What are the longevities of teeth and oral implants? Clin Oral Impl Res 2007;18:15–9.46. Pjetursson BE, Brägger U, Lang NP, Zwahlen M. Comparison of survival and complication rates of tooth-supported fi xed dental prostheses (FDPs) and implant-supported FDPs and single crowns (SCs). Clin Oral Implants Res 2007;18:97–113.47. Giannobile Wv, Lang NP. Are dental implants a panacea or should we better strive to save teeth? Editorial J Dent Res 2016;95:5–6.48. Pecora G, Andreana S, Covani U, De Leonardis D, Schiff erle RE. New directions in surgical endodontics: immediate implantation into an extraction socket. J Endod 1996;22:135–9.49. Silvestrin T. The role of implant dentistry in the specialty of endodontics. Endod Topics 2014;30:66–74.

THE AUTHOR, Leif K. Bakland, DDS, can be reached at [email protected].


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m i c r o b e s

AUTHOR

Markus Haapasalo, DDS, PhD, is a professor of endodontics at the University of British Columbia in Vancouver, Canada. He has published extensively on endodontic topics, including biofi lm, disinfection, microbiology and endodontic materials.Confl ict of Interest Disclosure: Dr. Haapasalo has commercial interest in two products named in the article: QMiX (Dentsply Tulsa Dental) and GentleWave (Sonendo).

Can We Eliminate Microorganisms From the Root Canal System?Markus Haapasalo, DDS, PhD

A B S T R AC T Bacteria in the root canal system are the causative factor of apical periodontitis (AP). Therefore, removing and killing these bacteria is the goal of endodontic treatment of AP. So far, none of the materials, methods and strategies employed has allowed elimination of all microbes in the root canal system. Emerging materials and equipment are moving us closer to predictable elimination of all root canal microbes.

Microbial invasion through the protective layers of the tooth, enamel, root surface cement and dentin into the pulp is the most

common cause of pulpal and periapical infl ammation and infection. Other pathways for the microbes include leaking fi llings, exposed dentin, trauma, cracks, lateral canals and even invaginations and evaginations (FIGURE 1). Pulp infl ammation starts before the invading bacteria enter the pulp from penetration of bacterial antigens released from the carious lesion through the dentinal tubules toward the pulp (FIGURE 2). These antigens are recognized by the defense system of the pulp, fi rst by antigen presenting dendritic cells, followed by a wider participation of the immune system and infl ammatory apparatus.1–3 Infection starts when bacterial cells enter the pulp. If left untreated, caries and bacterial invasion thus lead to pulp infl ammation, infection and eventually necrosis and apical periodontitis (FIGURE 3).

When the pulp has become necrotic, there are no defense mechanisms left in the root canal. The newcomers, microbes, quickly develop biofi lm ecosystems throughout the root canal system, attached to the root canal wall and to the necrotized pulp tissue (FIGURE 4). Periapical infl ammation starts when antigens start spreading through the apical foramina into the periapical tissue (FIGURES 5A

and 5B), similar to what happened when bacteria in carious dentin sent antigens (e.g., bacterial surface structures) toward the pulp.4 There is strong consensus based on classical studies that apical periodontitis is caused by microbes in the necrotic root canal, not by necrotic tissue per se (FIGURE 6).5,6 The pathogenesis of pulpitis and apical periodontitis differ, however, in one very important aspect: The pulp has no collateral circulation and is therefore vulnerable to irreversible infl ammation and necrosis to occur. The periapical area is different; collateral circulation secures continuing presence


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of apical periodontitis the root canal is occupied dominantly by strictly anaerobic bacteria (FIGURE 8).8–10 Typically, a few to several dozen different species are found, and combining different cases together, several hundred different microbial species of which > 99 percent are bacteria can be found in infected, necrotic root canals of teeth with apical periodontitis.11,12 The fl ora of root canals that have become reinfected has shifted to a more facultative microbiota (“semi-aerobic,” facultative bacteria tolerate both lack and presence of oxygen) instead of the strong anaerobic dominance typical of primary infections.

Treatment Strategy Part IFrom a clinical point of view, should

the composition of the fl ora be refl ected in the treatment strategy? Since the 1960s and even before, there have been numerous reports of the different virulence potential of various bacteria found in necrotic root canals,13–15 and frequently, new studies suggest that certain species can be regarded as “important pathogens.”16 There is probably much unnecessary confusion

of the host defense system, with a variety of different defense cell populations and active angiogenesis (FIGURE 7), which in most cases successfully fi ghts the invading bacteria and prevents them from establishing biofi lm communities outside the root canal system. Therefore, the goal of root canal treatment is to eliminate the microbes from the root canal system, ending the continuous feeding of antigens into the periapical area. Following this, normal wound healing mechanisms will usually take over and the periapical soft tissue infl ammatory lesion is gradually replaced again by healthy bone tissue.

The key questions are: How predictably and with what methods can we eliminate the microbes from the root canal system? If not all microbes can be eradicated, is there some threshold limit or other specifi c conditions under which complete healing can be obtained? Is prevention of reinfection of the root canal system different from prevention of the primary infection?

In this review, the nature of root canal infection is discussed, together with existing and potential future strategies to maximally reduce or even completely eliminate microbes from the root canal system. Extraradicular infections, where biofi lms have established their presence on root surface or in the periapical lesion requiring endodontic surgery for successful completion of the treatment, will not be discussed in this review.

Infection Part IBefore the development of anaerobic

culturing techniques for bacteria in the late 1960s and 1970s, many necrotic teeth with apical periodontitis were thought to be sterile.7 Developments in anaerobic microbiology eventually led to the current understanding that every tooth with necrotic pulp and periapical lesion has microbes (mostly bacteria) in the root canal space and that in most cases

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FIGURE 1. Pathways for bacteria to enter the pulp: 1) deep caries lesion, 2) enamel caries, 3) leaking fi lling, 4) cracks in tooth structure, 5) lateral canal, 6) opened dentin canals, 7) deep pocket to the apex, 8) bacteremia and 9) trauma exposing the pulp. Other pathways: cracked tooth, vertical root fracture, invagination and evagination. (All fi gures courtesy Artendo Enterprises Inc. if not otherwise stated)

FIGURE 3 . Maxillary lateral incisor with apical periodontitis. Bacteria may have entered the root canal e.g., via a lateral canal, dentin canals or a microfracture caused by trauma.

FIGURE 2. Histological section showing bacteria halfway in dentin and early pulpal reaction by infl ammation and a tiny micro abscess.

FIGURE 4 . A scanning electron microscope (SEM) image of necrotic pulp shows a mixture of necrotic tissue and bacteria of many diff erent morphotypes.


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related to pathogenicity and virulence. Pathogenicity is the ability to cause a disease while virulence is related to the severity of the infection. Virulent bacteria cause more serious, symptomatic, even spreading infections. Less virulent bacteria more often cause symptom-free local infections. Bacteria with both low and high virulence are pathogenic, but they can all cause periapical infl ammation.

Critical analysis of studies on endodontic microbiology shows that whenever bacteria survive the ecological conditions of the root canal, a periapical lesion will develop. In other words, development of the lesion (pathogenesis) is not dependent on the presence of certain specifi c, more pathogenic or virulent microbial species. Rather, the lesion develops as a response to any microbiota established in the canal space.5,6 It seems therefore that the endodontic infection (and the “pathogenic” lesion) differs from some other common host-parasite interactions in the oral cavity: Tooth surface plaque may or may not cause disease (caries) on the enamel and gingival crevice plaque may or may not cause gingivitis. Microbiota in the necrotic root canal, however, will always cause apical periodontitis. Therefore, the target in endodontic treatment is the elimination of any microbes in the root canal system, with no specifi c focus on certain microbial groups or species.

FIGURES 5. Schematic illustration of bacteria in the apical canal of a necrotic tooth facing a zone of defense cells (5A). Interaction between the root canal microbes and host defense cells initiates a variety of immunological chain reactions (5B). One result of this is activation of osteoclast cells, which remove the bone around the apical foramen.


FIGURE 6 . Classical studies have shown that sterile necrosis (tooth with necrotic pulp but with no bacteria) does not create a periapical lesion (left). Only when the necrotic canal contains microbes will a lesion will appear.

FIGURE 7. Histological specimen from a periapical lesion shows a small arteriole and great numbers of defense cells.

FIGURE 8 . A cultured sample from the tooth in fi gure 3 shows a mixed fl ora of mostly anaerobic bacteria, including at least two diff erent “black pigmented” species.

FIGURE 9. An SEM image of the surface of a multispecies oral biofi lm. Many diff erent types of bacteria can be seen. However, extracellular polymeric substance (EP) between cells is not visible in a conventional SEM image.

FIGURE 10 . A special FIB-SEM image of a biofi lm shows structures not seen in a conventional SEM image: blue arrows: EPS between cells; yellow arrows — microscopic water channels; green arrows — debris (waste) on biofi lm surface.


230 A P R I L 2 01 8

Infection Part II: Biofi lmBacteria in nature and in infections

exist either as planktonic, i.e., individual, single cells fl oating in a liquid medium, or as biofi lms, which are complex ecological structures usually attached to solid surfaces.17 It has been estimated that approximately 80 percent of human infections are biofi lm infections.18 Most oral infections are also biofi lm infections: caries, gingivitis, periodontitis, implantitis and apical periodontitis.19 The two states, planktonic and biofi lm, have great and clinically important differences: Planktonic bacteria are sensitive to common antimicrobial substances, whereas biofi lm bacteria are much more resistant. In other words, in endodontics the dentist is treating a resistant biofi lm infection.20

The key characteristics of a biofi lm are as follows: The biofi lm is attached (often fi rmly) to a solid surface, the cells inside biofi lm are surrounded by a gel consisting of different organic molecules and extracellular polymeric substance, and the metabolic activity of the microbial cells in the biofi lm is low and some may even be in a dormant state (viable but nonculturable). FIGURES 9 and 10 were taken with a regular scanning electron microscope (SEM) and a specialized focused ion beam SEM technique shows some key structural features of a multispecies bacterial biofi lm.

Anatomy, Advantages and Disadvantages

The root canal system in a tooth is where the effort to eliminate endodontic biofi lms takes place. This environment is a very special area of the human body, which can be both good and bad. The big advantage from the treatment point of view is that the root canal offers a space surrounded by hard, mainly inorganic walls of dentin. This allows use of harsh, even caustic disinfecting solutions such as concentrated sodium hypochlorite (NaOCl). Although the root canal system is not completely isolated from the surrounding soft tissues and bone, the limited connections via small apical foramina usually allow solutions to be kept inside the tooth;

only rarely do large volumes of liquid escape to the exterior. However, even though the chance of an NaOCl accident is small, the mere possibility may result in excessive caution for fear of the dramatic, negative consequences of an NaOCl extrusion accident.21,22 Disadvantages of the root canal anatomy include the frequent presence of narrow, deep fi ns, tiny anastomoses and connecting isthmuses,23 which cannot be reached with instruments and are also diffi cult to access by conventional irrigation (FIGURES 11–13). Further, the microanatomy of dentin, the 1–2.5 μm wide dentinal tubules (FIGURE 14), allows bacterial penetration deep into dentin (FIGURE 15) and renders them beyond the reach of endodontic instruments.24

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FIGURE 11. An SEM image of a root tip, from outside. Three major apical foramina can be seen, together with at least two lateral canal openings.

FIGURE 12. Cross section of a microCT scan of a mandibular molar reveals several hard-to-reach areas and also dentin debris packed into the fi ns.

FIGURE 13. An SEM image of a root canal shows numerous small dentinal tubule openings, an attached pulp stone and a lateral canal opening in the canal wall.

FIGURE 14 . An SEM view to instrumented root canal wall after NaOCl and EDTA irrigation. There are 10.000 — 25.000 dentinal tubules per square millimeter in root canal dentin. These are large enough to harbor bacteria.

FIGURE 15. Enterococcus faecalis bacteria deep inside a dentinal tubulus, beyond the reach of instruments.


A P R I L 2 0 1 8 231

Treatment Strategy Part II: Sterilization vs. Disinfection

Effective sterilization methods include the use of autoclave or dry heat at more than 100 degrees Celsius or high-energy gamma radiation. These methods are not suitable for infected root canals. Therefore, sterilization is not a correct word to describe the methods of reducing and eliminating microbes from infected root canal spaces. Instead, disinfection and antisepsis better describe what is done in endodontics. Antisepsis means destruction or prevention of proliferation of (pathogenic) microorganisms in order to prevent infection: the state of being free from living pathogenic organisms. Antiseptic compounds (such as iodine) are designed to be used in direct contact with living tissue, therefore their toxicity level is low.25,26 Disinfecting agents, such as NaOC1, are antimicrobial agents that are applied to the surface of nonliving objects to destroy microorganisms that are present.25–27 Disinfectants work by destroying the cell wall of microbes or interfering with the metabolism, but they will not necessarily kill all microorganisms. By defi nition, disinfecting solutions are not used in contact with living tissue, usually meaning “inside the human body.” As mentioned earlier, the mainly inorganic dentin walls create a special exception to the rule by effectively limiting the spreading of the solutions to living tissue where cells, vital connective tissue, nerves and the circulatory system are present. Bacterial spores are often resistant to disinfectants, but the challenge in endodontics to obtain a completely bacteria-free canal is not primarily related to the presence of bacterial endospores in the root canal. It is more a matter of the microanatomical conditions in the root canal system, the chemical nature of the tooth structures (in activation of disinfecting agents)28,29 and to some extent the necessary caution in the endodontic procedures to avoid disinfection complications.

Treatment Strategy Part III: Elimination of Root Canal Bacteria

Microorganisms, mostly bacteria, are killed or removed from the contaminated root canal system by a combination of methods and approaches. These include mechanical removal of necrotic and infected pulp tissue along with some of the root canal wall dentin by hand and rotary instruments and the washing action by irrigation solutions. Other methods are chemical dissolution and fl ushing of intradental soft tissues and dentin, removal of soft tissue and biofi lms by NaOCl and ultrasonic and other sound energies, chemical killing of microbes by disinfecting solutions and interappointment medication such as calcium hydroxide, killing by direct antimicrobial effect from some sealers and killing by long-term blocking of nutrients by a high-quality root fi lling and proper restoration of the tooth.20,24

Mechanical InstrumentationInstrumentation by hand and rotary

instruments impacts the root canal bacteria/biofi lms mainly in two ways. Firstly, infected pulp tissue and dentin is removed and secondly, space is created for effective irrigation. Together with antibacterial root canal fi llings, it is expected that most of the microbes will be eliminated. It is recognized that mechanical instrumentation cannot remove all microbes from the root canals.30,31 The classic studies in Sweden in the 1970s showed that while the number of bacteria in the canal was reduced even a thousandfold, sterility

(complete elimination of bacteria) was not achieved even after fi ve appointments of mechanical instrumentation and irrigation with saline.30,31 Newer studies have confi rmed these fi ndings.32,33 While these more recent studies confi rmed earlier fi ndings, they did show that increasing the size of apical preparation would further reduce the number of bacteria or colony forming units of bacteria on culture plate counts.

Many of the above studies have indicated that some of the canals can be rendered bacteria free by instrumentation. However, it is generally understood that the negative cultures refl ect more the lack of sensitivity of the sampling and culturing methods rather than true, complete absence of bacteria.34 It should be emphasized that sampling is usually done in areas of the main canal where instrumentation and irrigation have the strongest effect. New studies where dentin of the whole tooth has been crushed into powder and sensitive molecular biological methods have been used, much more bacteria are found than with traditional paper point and culturing methods.35,36

Irrigation With Antimicrobial and Other Solutions

Irrigation of the root canals can reach areas that instruments cannot.21,27 The “fl exibility” of liquids allows them, in theory, to penetrate into all areas in the canal system, many of which had not been touched by metallic fi les. Also, in the instrumented areas, the fi les have created a smear layer (FIGURE 16) and debris (FIGURE 17) that

FIGURE 16 . Smear layer on the wall of the main root canal after instrumentation. Several bacteria can be seen embedded in the layer.

FIGURE 17. Dentin debris packed by rotary fi les into the isthmus area between two canals in the same root. Even after 20 minutes of syringe-needle irrigation the debris had not been removed.


232 A P R I L 2 01 8

contains not only dentin but remnants of pulp tissue and bacteria and their antigens in all cases where the canal has been infected. Irrigants with specifi c properties can remove the smear layer and its contaminating microbial material. NaOCl followed by ethylene diaminetetraacetic acid (EDTA) will predictably and usually quite easily remove the smear layer; NaOCl removes the organic portion and EDTA the inorganic portion of the smear layer.21,27,34 Although not conclusively shown by studies, it is likely that if any part of the root canal system is bacteria free after chemomechanical preparation, it would be the main root canal. However, the few studies that have focused on removal of dentin debris from fi ns, isthmuses, lateral canals and apical foramina have shown that the available methods for cleaning root canals with instruments, irrigants and aids such as ultrasound are not able to remove all of the debris.37,38 Debris will always harbor microbes, therefore the inability to remove all debris gives a negative answer to the question asked in the title of this article. However, it is important to remember that in the world of infection and disease, the criteria for healing are almost never black and white. In the majority of oral infections, such as caries, gingivitis, periodontitis, peri-implantitis and pericoronitis, the question is clearly about threshold and balance, not about sterility.

NaOC1 is the key irrigant in the killing of root canal bacteria. In vitro studies done in a test tube using planktonic bacteria (single cells or small aggregates) have shown that even low concentration NaOCl kills 100 percent of various bacteria in seconds. These tests in the earlier days of endodontic research gave clearly a too optimistic view about the possibility of obtaining a completely bacteria-free root canal with endodontic disinfectants.21,27 Newer studies where bacteria are grown as

biofi lms20 have given a very different view. The level of killing is concentration dependent and so far there are no studies showing complete killing of all biofi lm bacteria (FIGURE 18). In a recent study of dentin biofi lm (bacterial biofi lm in dentinal tubules), 6% NaOCl used for 30 minutes and refreshed every 5 minutes killed only > 70 percent of the microbes in dentin. Importantly, there was very little additional killing after 10 minutes of exposure, despite refreshed NaOCl.39 Other studies have suggested that long-term NaOCl irrigation weakens dentin structure,40 therefore it is quite clear that long exposure to high-concentration NaOCl will not be the ultimate answer to obtain bacteria-free root canals.

However, there are indications that 5–6% NaOCl can detach biofi lms from the dentin surface, which can then be more easily fl ushed out of the canal by the continuing irrigation. However, biofi lm detachment by conventional syringe-needle NaOCl irrigation works only in the main root canal, not in dentinal tubules. Whether it can detach biofi lms in isthmus areas or lateral canals is not currently known.

Chlorhexidine (CHX) kills planktonic and biofi lm bacteria, but its effectiveness is at best the same as that of NaOCl and in many instances CHX is weaker.27 CHX does not dissolve tissue and has not been shown to be able to detach

biofi lms attached to the dentin surface. With respect to the ability of EDTA to kill microbes, most evidence shows it has little if any antimicrobial activity.21,27 The role of EDTA is important as it helps to remove the smear layer and at least some of the dentin debris with all the microbes contained in it. EDTA or citric acid combination products intend to combine smear layer removal with antimicrobial activity.21,27 So far, the highest documented antimicrobial effect has been demonstrated with QMiX (Dentsply Tulsa Dental, Tulsa, Okla.), which killed about 65 percent of dentinal tubule bacteria in three minutes, same as 6% NaOCl (FIGURE 19).41,42

Negative Pressure and Agitation of Irrigants

Several methods of agitation of the irrigating solutions in the root canals have been developed.27 It is likely that such emphasis to improve irrigation will have a positive effect. However, so far none of the methods have been shown to completely and predictably eliminate microbes from root canals. One of the newer methods includes the use of negative pressure irrigation (EndoVac, Kerr Dental, Orange, Calif.), which allows more effective irrigation of the apical canal space than traditional positive pressure syringe-needle irrigation.43 In negative pressure irrigation, there is no risk of irrigant extrusion to the periapical area, which

m i c r o b e s

FIGURE 18 . Biofi lm grown from a mixture of bacteria commonly found in infected root canals. The biofi lm was treated with 3% sodium hypochlorite for fi ve minutes, stained with “viability” stain and examined under confocal laser scanning microscopy (CLSM). Red areas show killed biofi lm microbes; in green areas the microbes are still alive.

FIGURE 19. Same CLSM technique as in fi gure 18 now used to measure killing of bacteria in dentinal tubules by diff erent endodontic irrigating solutions, sealers or other materials.


A P R I L 2 0 1 8 233

makes it possible to maximize the chemical cleaning and killing of microbes in this key location of the canal. Comparative studies have shown improvement by EndoVac over positive pressure irrigation in reducing bacteria but complete absence of the microbes remains a challenge.

EndoActivator (Dentsply Tulsa Dental) uses sonic vibration to facilitate irrigation. Again, while any valid method to improve cleaning is commendable, complete disinfection cannot be accomplished with sonic activation of irrigation solutions. Ultrasound uses higher frequency vibration than sonic activation, usually in the range of 20.000–35.000 Hz.44,45 Ultrasound used with an irrigant in the canals and pulp chamber works in two ways, cavitation and acoustic streaming. In cavitation, high-energy vacuum bubbles are formed, which in theory have the ability to release a concentrated energy burst at their target and cause a breakdown such as cell death. The diffi culty in endodontic cavitation so far has been that the vacuum bubbles have been estimated to last only for a few micrometers from the surface of the oscillating fi le. Acoustic streaming extends further in the canal system but many studies with equipment using so-called passive ultrasonic irrigation (PUI) show limited effect on bacterial reduction as compared to syringe-needle irrigation.46 ProUltra PiezoFlow (Dentsply Tulsa Dental) ultrasonic irrigation is active/

continuous ultrasonic irrigation because in addition to the ultrasonic energy there is a simultaneous fl ow of irrigant through the needle into the root canal (FIGURE 20).47 Detailed studies on reduction of intracanal bacteria are too few to draw conclusions. EndoUltra (Vista Dental, Racine, Wis.) is another new high-energy ultrasonic device with an optionally attached prefi lled irrigant canister (FIGURE 21).

Recently, a new type of endodontic cleaning device was introduced. The instrument (FIGURE 22) GentleWave (GW, Sonendo, Laguna Hills, Calif.) uses a wide spectrum of sound waves, including ultrasonic frequencies. The GW action is based on three main mechanisms. First,

high fl ow velocity (45 mL/min) of NaOCl hits an end plate of a nozzle in a treatment instrument, just above the pulp chamber fl oor. The liquid then spreads all around the pulp chamber and the root canal system.48 Second, the liquids (NaOCl, EDTA and water) are all degassed to remove micro air, which is known to reduce or eliminate the effects of cavitation. Third, GW irrigant fl ow happens under slight negative pressure in the canals, eliminating the risk of irrigant extrusion.48 A study on tissue dissolution by GW, ultrasound and conventional syringe-needle irrigation indicated that cavitation may in fact be contributing to the much faster (8 x) tissue dissolution by GW as compared to all other systems.48

FIGURE 20 . ProUltra PiezoFlow system for continuous fl ow ultrasonic activation.

FIGURE 21. A cordless, high-energy EndoUltra device with optional irrigant canister.

FIGURE 22. GentleWave (GW) instruments for front teeth and premolars (left) and molars (right).

FIGURE 23. A mandibular molar fi lled after minimal instrumentation and GW cleaning. Tiny apical lateral canals also fi lled. (Courtesy Dr. T.F. Baker)

FIGURE 24 . Hard tissue section of a molar mesial canal after 15/04 instrumentation, cleaning with GW and root fi lling with gutta-percha and GuttaFlow 2 sealer. The deep, microscopic fi n has also been cleaned and fi lled completely.


234 A P R I L 2 01 8

Other studies have shown the ability of GW to clean the main canal, isthmuses and lateral canals from pulp tissue remnants or from calcium hydroxide to allow high-quality root fi lling.49,50 The latter, complete calcium hydroxide removal, was only accomplished by GW but not by PUI or syringe-needle irrigation.50 A recent in vitro study comparing the effectiveness of GW and continuous ultrasonic irrigation to reduce bacterial numbers in contaminated root canals showed that GW predictably produced the highest level of cleanliness (FIGURES 23 and 24).51 A 12-month follow-up study after GW cleaning reported approximately 96 percent healing rate, thus clinically supporting the results of superior effectiveness in the in vitro studies.52

Interappointment MedicamentsIn multiappointment treatment,

the root canals are usually fi lled with a medicament with antimicrobial activity. Calcium hydroxide, CHX and iodine potassium iodide (IPI) or combinations of these are the most commonly used.20,34,53 The many studies of the effi cacy of such medicaments have clearly shown that they fail to predictably remove or kill all microbes from infected root canals.34 Studies comparing the reduction of bacteria after one and two appointment treatments have shown varying results.54

Root Filling, SealersRoot canal sealers have been known

to have antibacterial effects, depending on the type of sealer.55 Direct in vitro contact experiments showed variable killing of planktonic bacteria by sealers, but the effect usually faded away after a few hours or days. As seen previously with irrigation solutions, tests with planktonic bacteria have limited value in predicting the effi cacy of the compound against biofi lms. New studies using confocal microscopy and viability staining have

indicated killing of 30–50 percent of bacteria in dentinal tubules by sealers after 30 days of incubation. This is an important contribution in the elimination of residual microbes.56 Follow-up studies using 5% NaOCl and AH+ sealer (Dentsply Tulsa Dental) or bioceramic sealers reported up to 80 percent killing of biofi lm bacteria in root canals.57

Other Emerging StrategiesNanoparticles made of a wide variety

of materials are particles with a size between 1 and 100 nm. Many materials in the size of nanoparticles can have properties that are quite different from their usual characteristics. The appearance of the “new,” different properties may happen when the relative surface area of the material (due to small particle size) becomes much higher than the volume of the material. In medicine and in endodontics, antibacterial properties of nanomaterials are of particular interest. Nanoparticles could be part of irrigating solutions and intracanal medicaments and sealers.58 Research in use of nanoparticles in endodontics is likely to grow strongly in the next few years. Currently, the use of nanoparticles in root canal treatment is experimental.

Another relatively new group of antibacterial materials is antimicrobial peptides (AMPs).59 Recent publications on oral biofi lms and antimicrobial peptides have shown antibiofi lm effect stronger than reported for 2% chlorhexidine and even 6% NaOCl. A study where AMP was used alone or mixed with EDTA showed 80–90 percent killing of oral biofi lm bacteria in just minutes.59 It is possible that in the near future combination products will be available where nanoparticles and/or antimicrobial peptides are combined with conventional endodontic materials to boost their antimicrobial effect.60

ConclusionsNone of the materials, equipment

and strategies currently available for endodontics can predictably create a completely microbe-free root canal. Although 100 percent sterility is not required for complete healing of apical periodontitis, a high level of bacterial reduction is desirable. While this can often be achieved with currently available methods and materials, implementation of emerging new technology seems necessary in order to predictably obtain the highest level of cleaning and disinfection and thereby healing. ■REFERENCES

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14. Sundqvist G. Pathogenicity and virulence of black-pigmented gram-negative anaerobes. FEMS Immunol Med Microbiol 1993 Mar;6(2–3):125–37.15. Siqueira JF Jr., Magalhães FA, Lima KC, de Uzeda M. Pathogenicity of facultative and obligate anaerobic bacteria in monoculture and combined with either Prevotella intermedia or Prevotella nigrescens. Oral Microbiol Immunol 1998 Dec;13(6):368–72.16. Siqueira JF Jr, Rôças IN. Dialister pneumosintes can be a suspected endodontic pathogen. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002 Oct;94(4):494–8.17. Costerton JW, Cheng KJ, Geesey GG, Ladd TI, Nickel JC, Dasgupta M, Marrie TJ. Bacterial biofi lms in nature and disease. Annu Rev Microbiol 1987;41:435–64. 18. Costerton JW, Stewart PS, Greenberg EP. Bacterial biofi lms: A common cause of persistent infections. Science 1999 May 21;284(5418):1318–22. 19. Larsen T, Fiehn NE. Dental biofi lm infections — an update. APMIS 2017 Apr;125(4):376–384. doi: 10.1111/apm.12688. 20. Haapasalo M, Shen Y. Current therapeutic options for endodontic biofi lms. Endod Topics 2012;22:79-98.21. Basrani B, Haapasalo M. Update on endodontic irrigating solutions. Endod Topics 2013; 27:74–102.22. Guivarc’h M, Ordioni U, Ahmed HM, Cohen S, Catherine JH, Bukiet F. Sodium hypochlorite accident: A systematic review. J Endod 2017 Jan;43(1):16–24. doi: 10.1016/j.joen.2016.09.023.23. Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endod Topics 2005;10:3–29.24. Haapasalo M, Shen Y, Ricucci D. Reasons for persistent and emerging posttreatment endodontic disease. Endod Topics 2011;18:31–50.25. Spångberg L, Engström B, Langeland K. Biologic eff ects of dental materials. 3.Toxicity and antimicrobial eff ect of endodontic antiseptics in vitro. Oral Surg Oral Med Oral Pathol 1973;36:856–71.26. McDonnell G, Russell D. Antiseptics and disinfectants: activity, action, and resistance. Clin Microbiol Rev 1999;12:147–79.27. Haapasalo M, Shen Y, Qian W, Gao Y. Irrigation in endodontics. Dent Clin North Am 2010;54:291–312.28. Haapasalo H, Sirén E, Waltimo T, Ørstavik D, Haapasalo M. Inactivation of local root canal medicaments by dentin. Int Endod J 2000; 33:126–31.29. Portenier I, Haapasalo H, Rye A, Waltimo T, Ørstavik D, Haapasalo M. Inactivation of root canal medicaments by dentine, hydroxyapatite and bovine serum albumin. Int Endod J 2001; 34:184–8.30. Bystrom A, Sundqvist G. Bacteriological evaluation of the effi cacy of mechanical root canal instrumentation in endodontic therapy. Scand J Dent Res 1981;89:321–8.31. Bystrom A, Sundqvist G. Bacteriologic evaluation of the eff ect of 0.5 percent sodium hypochlorite in endodontic therapy. Oral Surg Oral Med Oral Pathol 1983;55:307–12.32. Dalton BC, Orstavik D, Phillips C, Pettiette M, Trope M. Bacterial reduction with nickel-titanium rotary instrumentation. J Endod 1998: 24: 763–7.33. Card SJ, Sigurdsson A, Orstavik D, Trope M. The eff ectiveness of increased apical enlargement in reducing intracanal bacteria. J Endod 2002: 28: 779–83 34. Haapasalo M, Endal U, Zandi H, Coil J. Eradication of

endodontic infection by instrumentation and irrigation solutions. Endod Topics 2005;10:72–102.35. Cook J, Nandakumar R, Fouad AF. Molecular- and culture-based comparison of the eff ects of antimicrobial agents on bacterial survival in infected dentinal tubules. J Endod 2007;33:690–2.36. Kho, P, Baumgartner JC. A comparison of the antimicrobial effi cacy of NaOCl/biopure MTAD versus NaOCl/EDTA against Enterococcus faecalis. J Endod 2006;32:652–5.37. Paqué F, Laib A, Gautschi H, Zehnder M. Hard-tissue debris accumulation analysis by high-resolution computed tomography scans. J Endod 2009;35:1044–7.38. Endal U, Shen Y, Årving K, Gao Y, Haapasalo M. A high-resolution computed tomographic study of changes in root canal isthmus area by instrumentation and root fi lling. J Endod 2011;37:223–7.39. Du T, Wang Z, Shen Y, Ma J, Cao Y, Haapasalo M. The eff ect of long-term exposure to endodontic disinfecting solutions on young and old Enterococcus faecalis biofi lms in dentin canals. J Endod 2014;40:509–14.40. Marending M, Paqué F, Fischer J, Zehnder M. Impact of irrigant sequence on mechanical properties of human root dentin. J Endod 2007;33:1325–8.41. Stojicic S, Shen Y, Qian W, Johnson B, Haapasalo M. Antibacterial and smear layer removal ability of a novel irrigant, QMiX. Int Endod J 2012;45:363–71.42. Ma J, Wang Z, Shen Y, Haapasalo M. A new noninvasive model to study the eff ectiveness of dentin disinfection using confocal laser scanning microscopy. J Endod 2011;37:1380–5.43. Miller TA, Baumgartner JC. Comparison of the antimicrobial effi cacy of irrigation using the EndoVac to endodontic needle delivery. J Endod 2010;36:509–11.44. Urban K, Donnermeyer D, Schäfer E, Bürklein S. Canal cleanliness using diff erent irrigation activation systems: A SEM evaluation. Clin Oral Investig 2017 Feb 9. doi: 10.1007/s00784-017-2070-x.45. Howard RK, Kirkpatrick TC, Rutledge RE, Yaccino JM. Comparison of debris removal with three diff erent irrigation techniques. J Endod 2011 Sep;37(9):1301–5. doi: 10.1016/j.joen.2011.05.008.46. Paiva SS, Siqueira JF Jr, Rôças IN, Carmo FL, Leite DC, Ferreira DC, Rachid CT, Rosado AS. Molecular microbiological evaluation of passive ultrasonic activation as a supplementary disinfecting step: A clinical study. J Endod 2013 Feb;39(2):190–4. doi: 10.1016/j.joen.2012.09.014.47. Malentacca A, Uccioli U, Zangari D, Lajolo C, Fabiani C. Effi cacy and safety of various active irrigation devices when used with either positive or negative pressure: An in vitro study. J Endod 2012 Dec;38(12):1622–6. doi: 10.1016/j.joen.2012.09.009.para 3.48. Haapasalo M, Wang Z, Shen Y, Curtis A, Patel P, Khakpour M. Tissue dissolution by a novel multisonic ultracleaning system and sodium hypochlorite. J Endod 2014;40:1178–81.49. Molina B, Glickman G, Vandrangi P, Khakpour M. Evaluation of root canal debridement of human molars using the GentleWave System. J Endod 2015 Oct;41(10):1701–5. doi: 10.1016/j.joen.2015.06.018.50. Ma J, Shen Y, Yang Y, Gao Y, Wan P, Gan Y, Patel P, Curtis A, Khakpour M, Haapasalo M. In vitro study of calcium hydroxide removal from mandibular molar root canals. J Endod 2015 Apr;41:553–8.

51. Zhang, D. Evaluation of the eff ectiveness of two irrigation systems in reducing bacterial load in root canals in vitro by quantitative real-time polymerase chain reaction. MSc Thesis, University of British Columbia, Canada. 2017.52. Sigurdsson A, Garland RW, Le KT, Woo SM. 12-month healing rates after endodontic therapy using the novel GentleWave System: A prospective multicenter clinical study. J Endod 2016 Jul;42(7):1040–8. doi: 10.1016/j.joen.2016.04.017.53. Kawashima N, Wadachi R, Suda H, Yeng T, Parashos P. Root canal medicaments. Int Dent J 2009 Feb;59(1):5–11.54. Sathorn C, Parashos P, Messer HH. Eff ectiveness of single- versus multiple-visit endodontic treatment of teeth with apical periodontitis: A systematic review and meta-analysis. Int Endod J 2005 Jun;38(6):347–55.55. Slutzky-Goldberg I, Slutzky H, Solomonov M, Moshonov J, Weiss EI, Matalon S. Antibacterial properties of four endodontic sealers. J Endod 2008 Jun;34(6):735–8. doi: 10.1016/j.joen.2008.03.012.56. Wang Z, Shen Y, Haapasalo M. Dentin extends the antibacterial eff ect of endodontic sealers against Enterococcus faecalis biofi lms. J Endod 2014;40:505–8. 57. Du T, Wang Z, Shen Y, Ma J, Cao Y, Haapasalo M. Combined antibacterial eff ect of sodium hypochlorite and root canal sealers against Enterococcus faecalis biofi lms in dentin canals. J Endod 2015 Aug;41:1294–8.58. Del Carpio-Perochena A, Kishen A, Shrestha A, Bramante CM. Antibacterial properties associated with chitosan nanoparticle treatment on root dentin and two types of endodontic sealers. J Endod 2015 Aug;41(8):1353–8. doi: 10.1016/j.joen.2015.03.020.59. Zhang T, Wang Z, Hancock RE, de la Fuente-Núñez C, Haapasalo M. Treatment of oral biofi lms by a D-enantiomeric peptide. PLoS One 2016 Nov 23;11(11):e0166997. doi: 10.1371/journal.pone.0166997.60. Wang D, Shen Y, DDS, Ma J, Hancock REW, Haapasalo M. Antibiofi lm eff ect of D-enantiomeric peptide alone and combined with EDTA in vitro. J Endod 2017;in press.

THE AUTHOR, Markus Haapasalo, DDS, PhD, can be reached at [email protected].

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A P R I L 2 0 1 8 237

c o n e b e a m c t

AUTHOR

Robert S. Roda, DDS, MS , is a board-certifi ed endodontist, past president of the American Association of Endodontists and an associate editor of the Journal of Endodontics. He practices in Scottsdale, Ariz.Confl ict of Interest Disclosure: None reported.

Can Use of Cone Beam Computed Tomography Have an Eff ect on Endodontic Treatment?Robert S. Roda, DDS, MS

A B S T R AC T Cone beam computed tomography (CBCT) has revolutionized endodontic diagnosis and treatment planning over the past decade. It allows the clinician to detect dental anatomy and disease states with much greater accuracy than regular two-dimensional radiography and is recommended as the imaging modality of choice for use in most aspects of endodontics. This paper reviews the most updated guidelines for use of CBCT to illustrate the effects this has on clinical endodontic practice.

Over the 122 years since Professor Otto Walkhoff exposed the fi rst dental radiograph,1 radiography has become an integral

part of all aspects of dentistry, including endodontics. Recently, cone beam computed tomography (CBCT) has been added to the armamentarium for endodontic therapy. As with any new technology, there has been a rapid growth in knowledge along with changes in implementation strategies that require clinicians to continually review all aspects of this new three-dimensional radiography.

Three-dimensional radiographic imaging began to be widely used in the 1980s in medicine, and ongoing developments in imaging have revolutionized the process of medical diagnosis. Progress in adapting medical CT

imaging to dentistry was somewhat slow with initial uses being mainly restricted to imaging craniofacial abnormalities and to aid in planning very complex oral and maxillofacial surgeries. This limited use of conventional CT in dentistry was due to the relatively high X-ray dosages of medical CT scanners and the high cost of imaging. The advent of cone beam CT in the late 1980s resulted in dramatically lower radiation exposure to patients, higher spatial resolution and lower costs. The technology soon became widely used in diagnostic imaging for dental implant placement and complex oral surgery procedures. It was the recent development of restricted or small fi eld of view (FOV) CBCT that brought it to the fore in endodontics. The much higher resolution of these smaller-imaged volumes allows detection of many of


238 A P R I L 2 01 8

the fi ne details in tooth structures and surrounding tissues and that information can have an impact on clinical decision-making. The impact of CBCT in endodontics is refl ected in the scientifi c literature. Each year for the last decade, there have been an increasing number of articles published regarding CBCT.

A quick search of scientifi c articles and case reports in the Journal of Endodontics revealed that in 2006 only three articles mentioned CBCT. In 2011, that number had risen to 39; in 2016, there were 64 articles. The interest in this topic is clearly increasing.

What Is Cone Beam Computed Tomography?

Traditional 2-D radiography produces a fl at image on a fi lm or sensor that is made up of the shadows of all of the structures between the X-ray source and the detector (fi lm or digital sensor). These structures appear as overlapped and, while the image resolution is excellent, the geometries are distorted and true sizes of biological structures are not discernible. Superimposed anatomic structures impede visualization of subjacent structures and disease-related changes. In dentistry, this renders diagnosis diffi cult especially in the maxillary posterior region. By making multiple 2-D images from differing

incident beam angles, three-dimensionality can be inferred but the distortions of the image still make defi nitive diagnosis diffi cult and sometimes impossible.

Three-dimensional radiography was developed to overcome these disadvantages. Hounsfi eld introduced computed tomography in the 1970s and the technology has been advancing ever since. Conventional medical CT scanners produce a fan-shaped beam that rotates around the patient multiple times in a helical or spiral motion to create image slices that are stacked one upon the other. This process is time-consuming and results in a large radiation exposure to the patient2,3 and artifacts induced by patient movement. CBCT reduces the time of acquisition of the image and reduces exposure of the patient to X-rays by using a cone-shaped beam that rotates between 180 and 360 degrees around the patient with the beam hitting a detector on the opposite side of the patient’s head similar to panoramic radiography. A third type of 3-D radiography is the micro-CT (μCT). It produces 3-D images of exceedingly fi ne detail and clarity, and it is widely used in endodontic research but is not adaptable to the clinical setting.4

The imaged area is called a volume that is made up of voxels. Voxels are

isotropic units (cubes) that make up the image. Generally, the smaller the voxel, the higher the spatial resolution of the imaged volume.4 Commonly used voxel sizes in endodontics range from 0.076 to 0.6 mm. Because a computer in the scanner processes the data, the limitations on resolution imposed by larger voxel sizes can often be overcome with sophisticated algorithms.

Other parameters that affect image quality include the peak kilovoltage (kVp), milliampere seconds (mA-s) and FOV that is imaged. Of these, the FOV is of critical importance. Generally, the smaller the FOV, the better the resolution of the images produced, which, in endodontics, allows for more accurate diagnosis and treatment planning decisions because many of the factors leading to better outcomes are too small to detect on larger FOV images (FIGURES 1). In addition, smaller FOV volumes expose the patient to less radiation.5

Rather than the overlapped shadows in 2-D radiography, CBCT produces a 3-D image that is made up of slices. But unlike medical CT devices, these slices are combined into a volume that can be inspected in many ways. The structures in the imaged area can be seen from any of the three traditional anatomic planes of view (sagittal, coronal and axial)

c o n e b e a m c t


FIGURES 1. 2-D periapical image of asymptomatic tooth No. 9 (1A). 3-D medium FOV CBCT image of tooth No. 9 (sagittal plane) (1B). Arrows show suspected PA low-density area consistent with asymptomatic apical periodontitis. 3-D small FOV CBCT image of tooth No. 9 (sagittal plane) showing normal periapical architecture (1C).


A P R I L 2 0 1 8 239

but also, depending on the rendering software, the structures can be viewed from any angle because the voxels are isotropic. These structures rendered are geometrically accurate and actual sizes of the structures can be measured using tools available in most of the software readers. Therefore, the image is viewed in slices (one layer or sheet of voxels), overlapping of structures does not occur and a true representation of the tissues can be seen, enhancing diagnostic yield. The volume data is required to be provided in the recognized DICOM format so that the volumes can usually be shared and viewed by clinicians using many different software readers, although some manufacturers of CBCTs have yet to make their volumes universally accessible.

Compared to 2-D radiography, the disadvantages of CBCT imaging are

few. The resolution of the 3-D image is still not comparable to conventional radiographs.4 CBCT is prone to the creation of streaking (beam hardening)6 and volumetric distortion (cupping)7 artifacts in the presence of very radiodense materials such as dental restorations, surgically implanted metallic materials and root canal obturation materials (FIGURE

2). This limits the usefulness of the technology for assessment of restorative and postendodontic complications such as vertical root fractures or strip perforations.8 Also, the incident radiation doses to the patient, while very small, are still higher than with 2-D radiography.9,10

Finally, the cost of purchasing and maintenance of CBCT equipment is generally much higher than that for 2-D radiography. The convenience of having a CBCT in the offi ce is

high and most medium FOV units can also produce a digital panoramic radiograph thus replacing the traditional panoramic machine. The proliferation of stand-alone imaging centers in dentistry provides an alternative to the purchase and maintenance of CBCT equipment. These centers can usually provide services with various CBCT units with multiple FOVs, frequently at a lower cost to the patient. Because they produce more volumes, imaging centers can negotiate better fees from radiologists for reading the volumes while making access to professional interpretation much easier. Manufacturers are now producing CBCT units with FOVs, higher resolution and artifact reduction software making the decision to purchase a unit or use an imaging center diffi cult.

FIGURE 2A .

FIGURE 2D. FIGURE 2E .

FIGURE 2B .

FIGURE 2C .

F IGURES 2 . 2-D periapical radiograph of tooth No. 9 with a silver point endodontic fi lling (2A). 3-D CBCT slice from the axial plane showing beam hardening as streaks on the image (2B). 3-D CBCT slice from the sagittal plane showing the beam-hardening artifact as a thick black area lingual to the full length of the silver point (2C). 2-D periapical radiograph of tooth No. 20 (2D). 3-D CBCT slice from the sagittal plane showing apparent enlargement of the post (volumetric or “cupping” artifact) (2E).


240 A P R I L 2 01 8

AAE/AAOMR Joint Position StatementRecently, the American Association

of Endodontists (AAE) and the American Academy of Oral and Maxillofacial Radiology (AAOMR) updated their joint position statement on the use of CBCT in endodontics.5 The updated statement provides guidance on the use of CBCT in various clinical situations where it is applicable. It is not intended to substitute for a clinician’s independent judgment regarding the needs of a patient, but the usefulness of this statement is valuable to clinicians performing endodontic diagnosis and treatment. It states that CBCT should only be used when the needs of imaging cannot be met with lower- dose conventional 2-D radiography, so it is not recommended for routine use on all patients. After a thorough evaluation of the patient including the patient’s medical and dental history and a thorough clinical examination, the clinician will then decide whether the unique situation of that patient requires the use of CBCT imaging to complete the diagnosis. The position paper also states that, for most endodontic applications, small or limited FOV CBCT is preferred although for large or multifocal lesions with possible systemic origin larger FOV imaging can be selected.

The AAE/AAOMR joint position statement further recommends that ALARA principles be followed when selecting an imaging modality. ALARA means choosing an imaging technology that achieves the diagnostic goals while using a radiation dose that is “as low as reasonably achievable.” Selected radiation dosages for some commonly used radiography modalities are provided in the TABLE and show the relative incipient radiation and

tissue susceptibilities in units called microsieverts (μSv). Limited FOV CBCT exposes the patient to reduced dosages compared to larger FOVs and so, where practical, compliance with the ALARA principle is best achieved using small FOV. It is particularly important in children (up to and including the age of 18) to reduce any exposure to radiation when the opportunity to use lower-dose imaging modalities is possible.11

Finally, the AAE/AAOMR statement recommends that if a clinician has a question regarding image interpretation, an oral and maxillofacial radiologist should read the volume. With small or limited FOV CBCT, the imaged area usually contains tissues with which dentists are familiar, but even in these familiar areas, unusual or unexpected fi ndings should trigger consultation with a radiologist. In a recent study, an oral radiologist detected more incidental fi ndings in more than 200 limited FOV scans than endodontic graduate students could, suggesting that even small FOV scans should be routinely read by a radiologist.12 With medium or large FOV volumes and image regions that are outside the usual areas of expertise for dentists (such as the base of the skull or anterior spine), prudence suggests that those scans should be read by a radiologist.

IndicationsThe AAE/AAOMR joint position

statement lists recommendations regarding the clinical use of CBCT in endodontics.5 These recommendations are a list of the possible clinical indications for use of CBCT. While not all of these situations would routinely require use of CBCT, there are situations where the use of 3-D imaging is especially helpful in the diagnosis and treatment planning of endodontically involved teeth. Preoperative 2-D radiographs are an integral part of the initial diagnosis of patients and should be used in all cases, and 3-D CBCT should only be used in those cases where more information is needed to answer any unanswered diagnostic questions.

Diffi cult DiagnosisEndodontic disease can present in

a variety of ways and it can be diffi cult to interpret confl icting diagnostic information pointing to a variety of pathological conditions. It may be challenging to determine with conventional diagnostic techniques whether a patient is suffering from endodontic pain, pain of musculoskeletal origin, pain from sinusitis or even neurogenic or atypical facial pain. Even

e y e b r o wc o n e b e a m c t

TABLE

Comparison of Approximate Radiation Dosages

Source Dosage (μSv)

Annual background radiation 3000

4 BW (digital or F-speed, rectangular collimation) 5

FMX (digital or F-speed, rectangular collimation) 35

FMX (D-speed, round collimation) 388

Panoramic (digital 2 brands) 14–24

Chest radiograph 100

Lower GI tract radiograph 8000

CT chest 7000

CT maxillofacial large FOV mean (range) 212 (46–1073)

CT maxillofacial medium FOV mean (range) 177 (9–560)

CT maxillofacial small FOV mean (range) 84 (5–652)

Source: Adapted from references 3, 9 and 10


A P R I L 2 0 1 8 241

when all non-endodontic etiologies for a patient’s symptoms have been ruled out, it may still be diffi cult to identify the tooth that may be the origin of the patient’s chief complaint. This is related to the limitations in current clinical testing and intraoral 2-D radiography.

In many of such diffi cult situations, CBCT can provide information that can lead to a correct diagnosis. The recommendation of the AAE/AAOMR position statement is that limited FOV CBCT should be considered the imaging modality of choice for diagnosis in patients who present with contradictory or nonspecifi c clinical signs and symptoms associated with untreated or previously endodontically treated teeth. The superior

ability of CBCT to provide information that can help identify endodontic disease has been demonstrated in several ex vivo and clinical studies.13–18 An example of where CBCT was essential in diagnosing a diffi cult case is shown in FIGURES 3.

Anatomic VariationsThe success of root canal therapy

depends on identifying, cleaning and sealing all of the root canal system. Because of the anatomic variations and complexities of the root canal system, 2-D radiography frequently is inadequate in revealing such things as the number and the shapes of canals and roots. The results of leaving untreated spaces in the canal system or not

detecting severe curvatures in canals can lead to separated instruments, canal transportation and retention of necrotic tissue/bacteria in the canals. Lack of healing or posttreatment endodontic disease may be the eventual outcome. Use of CBCT can provide a much more accurate and detailed image than 2-D radiography and help avoid these undesirable outcomes (FIGURES 4). Studies have shown a strong correlation between anatomic information obtained from CBCT volumes and anatomic studies using sectioning or histologic methods in anatomic studies of teeth.19,20 Improvement in detection of second mesiobuccal canals in maxillary molars has also been shown.21


FIGURE 3D. FIGURE 3E .

FIGURE 3F.

FIGURES 3 . Patient presented with long-term mild pain and accompanying symptoms of maxillary sinusitis. Clinical examination (including this 2-D periapical image) did not lead to diagnosis (3A). 2-D distal angle periapical radiograph of tooth No. 2 showing no defi nitive evidence of pathosis (3B). 3-D CBCT slice from the sagittal plane showing low-density periapical area consistent with apical periodontitis. Note the thickening of the sinus membrane (3C). 3-D CBCT slice from the coronal plane showing that the low-density area is confi ned to the palatal aspect of the mesial roots (3D). 3-D CBCT slice from the axial plane showing the low-density area (arrows) (3E). 2-D periapical radiograph showing completed nonsurgical re-treatment 79 months postoperatively. The patient’s symptoms had resolved completely (3F).


242 A P R I L 2 01 8

Intraoperative UseWhile not as routine, CBCT may

occasionally be used intraoperatively. If during endodontic therapy it becomes apparent that not all of the canals have been found and no pretreatment CBCT images are available, the access can be sealed and a CBCT scan exposed to reveal untreated canal spaces. This is especially useful when treating teeth with extensively calcifi ed canals, thus reducing the risk of root perforation.

Absent any questions about treatment outcomes, the posttreatment radiographic image need only be 2-D.5

Tooth FractureCracks in teeth can be diffi cult to

diagnose. Detection of tooth fractures, while complicated, is important because these fractures often affect the tooth’s prognosis. Undiscovered fractures can lead to treatment efforts that are in vain. Two-dimensional radiography rarely will detect a fracture in a tooth because the X-ray beam must be perfectly aligned with the fracture plane to allow it to be seen on the radiograph. CBCT imaging can help in visualizing fractures, but whether the fracture itself can be seen depends on the length and the width of the fracture, the spatial resolution of the volume and the presence of artifacts due to adjacent radiopaque


FIGURE 4A . FIGURE 4B .FIGURE 4C .

FIGURES 4 . Tooth No. 19 is symptomatic fi ve years after initial endodontic treatment. A mesial PA radiolucency is evident (4A). 3-D CBCT slice from the axial plane showing an untreated fourth canal (DL) (4B). Seven months after nonsurgical re-treatment, the 2-D PA radiograph shows partial shrinkage of the mesial PA radiolucency and the patient is asymptomatic (4C).

restorative and endodontic materials. Two recent systematic reviews have indicated that direct detection of fracture in endodontically treated teeth is unreliable due to these factors.8,22 CBCT imaging can, however, be helpful in detecting the patterns of bone loss and alterations in the periodontal ligament space that usually accompany a tooth fracture. These changes in the appearance of the periodontium surrounding a cracked root are frequently not visible on a 2-D radiograph but can be more easily detected in the CBCT volume (FIGURES 5). Both laboratory and clinical studies indicate that CBCT imaging can show the presence of root fractures, even if the fracture itself remains diffi cult to visualize.23–26

Posttreatment Endodontic DiseaseMillions of endodontically diseased

teeth are treated every year through nonsurgical endodontic therapy. While this treatment modality enjoys a very high rate of clinical success,27,28 there are some cases that will exhibit endodontic posttreatment disease. The AAE/AAOMR position paper5 points out that limited FOV CBCT may be the imaging modality of choice when evaluating cases of nonhealing that may need either surgical or nonsurgical re-treatment. The CBCT allows for

very detailed analysis of factors that may have led to the posttreatment disease, such as untreated canals, (FIGURES 4) the adequacy of previous instrumentation and obturation, root perforations, periodontal disease, furcation involvements, vertical root fractures and the patterns of bone loss and locations of periapical lesions. By detecting otherwise hidden factors affecting prognosis, better treatment planning choices can be made.

In some instances, CBCT images can identify factors that would indicate that re-treatment (either surgical or nonsurgical) would have a poor prognosis. Lacking such information could lead to re-treatment procedures with high likelihood of failure. This may be avoided by using CBCT to evaluate teeth with posttreatment disease.

When planning for surgical re-treatment, the use of CBCT has many benefi ts. One will be able to see the spatial relationships between the affected tooth and adjacent anatomical structures such as the maxillary sinus29,30 (FIGURES 6), adjacent tooth root proximity, buccal bone thickness31 and the path of the inferior alveolar nerve32,33 and blood vessels. By accurately locating these structures, surgical complications such as sinus perforation, damage to adjacent teeth, paresthesia/dysesthesia and severe hemorrhage can generally be avoided.


A P R I L 2 0 1 8 243

Dental TraumaThe AAE/AAOMR joint position

statement recommends that CBCT be the imaging modality of choice in the diagnosis and management of limited dentoalveolar trauma.5 The 3-D view will aid in the diagnosis of horizontal root fractures, alveolar fractures and luxation injuries. More extensive trauma may also require other imaging modalities.

The clinical value of using CBCT must be weighed against the increased radiation dosage especially in young patients. But in general, the benefi ts of using CBCT outweigh the risks such as missed fractures both in teeth and bone. Often the need for multiple 2-D images may result in more radiation than that from taking a CBCT image. Adjusting the exposure parameters of the CBCT can also reduce the radiation exposure while not impacting the diagnostic accuracy.34

ResorptionRoot resorption presents signifi cant

challenges in attempts to retain such teeth. The extent of the resorption and its possible effect on the structural integrity of the tooth posttreatment requires careful consideration. CBCT imaging has been found to be more accurate than 2-D radiography in detecting and


FIGURES 5. 2-D periapical radiograph showing a large periapical radiolucency that surrounds the root and extends up toward the cervical one-third of the root on the distal surface (5A). 3-D CBCT slice from the sagittal plane showing that the distal low-density area extends up to the crest of bone (5B). 3-D CBCT slice from the axial plane showing that the low-density area is very narrow mesiodistally. A periodontal probe could reach to the apex. The patient’s tolerance for risk was low and so an extraction was performed whereupon a vertical fracture was found in the root (5C).

FIGURE 6A .FIGURE 6B .

FIGURE 6C .

FIGURE 6D.

FIGURES 6 . 2-D periapical radiograph showing a symptomatic upper premolar in apparent close proximity to the maxillary sinus (6A). 3-D CBCT slice from the sagittal plane showing evident communication between the apical low-density area and the maxillary sinus (6B). Clinical microscopic view of the preexisting perforation into the sinus (6C). Six months after apical microsurgery, the patient is asymptomatic (6D).


244 A P R I L 2 01 8


FIGURE 7A .


FIGURE 8D.

FIGURE 8E .

FIGURE 8C .

FIGURE 7B .

FIGURE 7C .

FIGURES 7. 2-D periapical and bitewing radiographs showing a small area of resorption on tooth No. 3 (7A). 2-D periapical radiograph from a distal angulation is not very helpful in assessing the prognosis (7B). 3-D CBCT slice from the axial plane showing the extent of the resorption and that it has opened a communication between the pulp space and the periodontium. The prognosis was unfavorable and the patient elected to extract the tooth (7C).

FIGURE 8 . 2-D periapical radiograph of tooth No. 6 indicates a radiolucency consistent with external root resorption (arrow) (8A). 2-D periapical radiograph from a distal angulation indicates that it is on the palatal side (since the canal moved most to the mesial)(8B). There was no discontinuity in the structure of the tooth in any view on the CBCT. This axial plane view shows a suspicious notch (arrow) in the bone palatal to the tooth (8C). 3-D CBCT slice from near the sagittal plane indicates that the “lesion” is simply an anatomic variation. It is called the canalis sinuosus (Dr. Bruno Azevedo – OMR, personal communication) and contains the anterior superior alveolar nerve and blood vessels (8D). 3-D rendering showing the palatal view of this variant (arrows). If the CBCT had not been made, this patient would have possibly undergone unnecessary, potentially invasive treatment for a disease that did not exist (8E).


A P R I L 2 0 1 8 245

determining the extent of a resorptive lesion in a tooth35–37 (FIGURES 7). Prior to the availability of CBCT, invasive exploratory procedures to determine the extent of lesions were often necessary. Such exploratory procedures — whether surgical or nonsurgical — combined with treatment efforts would sometimes result in a poor prognosis for long-term retention. With the possibility of obtaining detailed preoperative information using CBCT imaging, managing cases of teeth with root resorption has improved.

Another advantage of using CBCT for assessment of suspected resorption is that occasionally the imaging will reveal that what appeared to be resorption radiographically is, in fact, something else (FIGURES 8). In such cases, patients are spared unnecessary treatment and cost.

Treatment Outcomes and Healing Assessment

Treatment outcomes are evaluated following completion of endodontic therapy. This may be to determine improvements or recurrence in patients’ subjective symptoms, clinical fi ndings and radiographic appearances or upon patients’ requests. The radiographic fi ndings that are indicative of healing or nonhealing of endodontic disease have been infl uenced by two scientifi cally validated systems to assess two-dimensional radiographs: the Strindberg criteria38 and the periapical index (PAI).39

In light of the superior ability to detect periapical low-density areas and other changes that may indicate endodontic posttreatment disease using CBCT,15 concerns have arisen regarding the validity of previous endodontic outcomes studies.40 Complicating that concern is the lack of a universally accepted system for endodontic outcomes assessment using CBCT.41 While some research has been published addressing this

recently,42,43 there is still no consensus. For example, it is common to fi nd that an asymptomatic, endodontically treated tooth may exhibit a low-density periapical area as an incidental fi nding on a CBCT volume. If this is not visible on a 2-D radiograph and there are no subjective symptoms or clinical fi ndings, it is diffi cult to tell if such a “lesion” represents disease or simply delayed healing. The ability to fi nd suspected pathosis by using CBCT has exceeded the ability to determine accurately what is occurring in such instances.

The AAE/AAOMR joint position statement5 recommends that absent signs or symptoms, 2-D periapical radiographs are the imaging modality of choice for outcome evaluation following endodontic therapy. If, however, CBCT imaging was used preoperatively, the statement does make the allowance that the same modality may be used postoperatively to assess the outcome. If there are signs and symptoms of posttreatment disease, it refers back to the recommendation to use CBCT for assessment of this. The ambiguity of these recommendations refl ects a lack of consensus that may be gained in the future. One can expect research to improve the ability to interpret endodontic outcomes using CBCT technology; for now practitioners with minimal experience should be encouraged to seek advice from oral and maxillofacial radiologists or other specialists with experience in the area.

Eff ect on Treatment PlanningThe most compelling evidence of

the importance of CBCT in endodontic diagnosis and treatment planning is found in three recent studies44–46 where clinicians were presented with complete diagnostic information including 2-D radiographs but not CBCT volumes. These subjects completed endodontic

treatment plans for the teeth in question and were then presented with the CBCT volumes and asked if this information would change their treatment plans. The plans were changed in 35 to 62 percent of the cases illustrating the infl uence that CBCT information can have on endodontic treatment planning.

ConclusionAs more research is completed

regarding CBCT imaging, specifi c guidelines and clinical best practices will evolve. In the future, one can expect improvements in 3-D imaging technology to enhance resolution akin to the micro-CT. Regardless of what the future brings in this rapidly growing fi eld, the question now is: Can use of CBCT have an effect on endodontic treatment? The answer to this question, as posed in the title of this article, appears to be an emphatic yes. ■

REFERENCES

1. Grossman LI. A brief history of endodontics. J Endod 1982;8:S36–S40 (special issue).2. Nardi C, Talamonti C, Pallotta S, Saletti P, Calistri L, Cordopatri C, et al. Head and neck eff ective dose and quantitative assessment of image quality: A study to compare cone beam CT and multislice spiral CT. Dentomaxillofac Radiol 2017;20170030.3. Radiological Society of North America. Radiation Dose in X-ray and CT Exams. 2017. www.radiologyinfo.org/en/info.cfm?pg=safety-xray. Accessed July 15, 2017.4. Nair MK, Levin MD, Nair UP. Radiographic Interpretation. In: Hargreaves KMB, Berman LH, Rotstein, I, ed. Cohen’s Pathways of the Pulp. 11th ed. St Louis: Elsevier; 2016:33–70.5. AAE/AAOMR. Use of Cone Beam Computed Tomography in Endodontics — 2015/2016 Update. 2016 www.aae.org/uploadedfi les/clinical_resources/guidelines_and_position_statements/conebeamstatement.pdf. Chicago; 2016. Accessed July 16, 2017.6. Helvacioglu-Yigit D, Demirturk Kocasarac H, Bechara B, Noujeim M. Evaluation and Reduction of Artifacts Generated by Four Diff erent Root-End Filling Materials by Using Multiple Cone Beam Computed Tomography Imaging Settings. J Endod 2016; 42(2):307–314.7. Decurcio DA, Bueno MR, de Alencar AH, Porto OC, Azevedo BC, Estrela C. Eff ect of root canal fi lling materials on dimensions of cone beam computed tomography images. J Appl Oral Sci 2012; 20(2):260–267.8. Chang E, Lam E, Shah P, Azarpazhooh A. Cone beam computed tomography for detecting vertical root fractures in endodontically treated teeth: A systematic review. J Endod 2016; 42(2):177–185.


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9. Ludlow JB. Dose and risk in dental diagnostic imaging: With emphasis on dosimetry of CBCT. Kor J Oral Maxillofac Radiol 2009;39:175–184.10. Ludlow JB, Timothy R, Walker C, Hunter R, Benavides E, Samuelson DB, et al. Eff ective dose of dental CBCT — a meta analysis of published data and additional data for nine CBCT units. Dentomaxillofac Radiol 2015;44(1):20140197.11. Abdelkarim AA. Appropriate use of ionizing radiation in orthodontic practice and research. Am J Orthod Dentofac Orthopedics 2015;147(2):166–168.12. Oser DG, Henson BR, Shiang EY, Finkelman MD, Amato RB. Incidental fi ndings in small fi eld of view cone beam computed tomography scans. J Endod 2017; 43(6):901–904.13. Patel S, Wilson R, Dawood A, Mannocci F. The detection of periapical pathosis using periapical radiography and cone beam computed tomography — part 1: Preoperative status. Int Endod J 2012;45(8):702–710.14. Abella F, Patel S, Duran-Sindreu F, Mercade M, Bueno R, Roig M. Evaluating the periapical status of teeth with irreversible pulpitis by using cone beam computed tomography scanning and periapical radiographs. J Endod 2012;38(12):1588–1591.15. Cheung GS, Wei WL, McGrath C. Agreement between periapical radiographs and cone beam computed tomography for assessment of periapical status of root fi lled molar teeth. Int Endod J 2013;46(10):889–895.16. Sogur E, Grondahl HG, Baksi BG, Mert A. Does a combination of two radiographs increase accuracy in detecting acid-induced periapical lesions and does it approach the accuracy of cone beam computed tomography scanning? J Endod 2012; 38(2):131–136.17. Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endod J 2009;42(6):507–515.18. Uraba S, Ebihara A, Komatsu K, Ohbayashi N, Okiji T. Ability of cone beam computed tomography to detect periapical lesions that were not detected by periapical radiography: A retrospective assessment according to tooth group. J Endod 2016;42(8):1186–1190.19. Michetti J, Maret D, Mallet JP, Diemer F. Validation of cone beam computed tomography as a tool to explore root canal anatomy. J Endod 2010;36(7):1187–1190.20. Blattner TC, George N, Lee CC, Kumar V, Yelton CD. Effi cacy of cone beam computed tomography as a modality to accurately identify the presence of second mesiobuccal canals in maxillary fi rst and second molars: A pilot study. J Endod 2010;36(5):867–870.21. Vizzotto MB, Silveira PF, Arus NA, Montagner F, Gomes BP, da Silveira HE. CBCT for the assessment of second mesiobuccal (MB2) canals in maxillary molar teeth: Eff ect of voxel size and presence of root fi lling. Int Endod J 2013;46(9):870–876.22. Talwar S, Utneja S, Nawal RR, Kaushik A, Srivastava D, Oberoy SS. Role of cone beam computed tomography in diagnosis of vertical root fractures: A systematic review and meta-analysis. J Endod 2016;42(1):12–24.23. Edlund M, Nair MK, Nair UP. Detection of vertical root factures by using cone beam computed tomography: A clinical study. J Endod 2011;37(6):768–772.24. Brady E, Mannocci F, Brown J, Wilson R, Patel S. A comparison of cone beam computed tomography and periapical radiography for the detection of vertical root

fractures in nonendodontically treated teeth. Int Endod J 2014;47(8):735–746.25. Metska ME, Aartman IH, Wesselink PR, Ozok AR. Detection of vertical root fractures in vivo in endodontically treated teeth by cone beam computed tomography scans. J Endod 2012;38(10):1344–1347.26. Leader DM. CBCT is valuable for diagnosis of tooth fracture. Evid Based Dent 2015;16(1):23–24.27. Salehrabi R, Rotstein I. Epidemiologic evaluation of the outcomes of orthograde endodontic re-treatment. J Endod 2010;36(5):790–792.28. Lazarski MP, Walker WA, Flores CM, Schindler WG, Hargreaves KM. Epidemiological evaluation of the outcomes of nonsurgical root canal treatment in a large cohort of insured dental patients. J Endod 2001;27(12):791–796.29. Lavasani SA, Tyler C, Roach SH, McClanahan SB, Ahmad M, Bowles WR. Cone beam computed tomography: Anatomic analysis of maxillary posterior teeth — impact on endodontic microsurgery. J Endod 2016;42(6):890–895.30. von Arx T, Fodich I, Bornstein MM. Proximity of premolar roots to maxillary sinus: A radiographic survey using cone beam computed tomography. J Endod 2014;40(10):1541–1548.31. Bornstein MM, Lauber R, Sendi P, von Arx T. Comparison of periapical radiography and limited cone beam computed tomography in mandibular molars for analysis of anatomical landmarks before apical surgery. J Endod 2011;37(2):151–157.32. Aminoshariae A, Su A, Kulild JC. Determination of the location of the mental foramen: A critical review. J Endod 2014;40(4):471–475.33. Koivisto T, Chiona D, Milroy LL, McClanahan SB, Ahmad M, Bowles WR. Mandibular Canal location: Cone beam computed tomography examination. J Endod 2016;42(7):1018–1021.34. Jones D, Mannocci F, Andiappan M, Brown J, Patel S. The eff ect of alteration of the exposure parameters of a cone beam computed tomographic scan on the diagnosis of simulated horizontal root fractures. J Endod 2015;41(4):520–525.35. Yi J, Sun Y, Li Y, Li C, Li X, Zhao Z. Cone beam computed tomography versus periapical radiograph for diagnosing external root resorption: A systematic review and meta-analysis. Angle Orthod 2017;87(2):328–337.36. Durack C, Patel S, Davies J, Wilson R, Mannocci F. Diagnostic accuracy of small volume cone beam computed tomography and intraoral periapical radiography for the detection of simulated external infl ammatory root resorption. Int Endod J 2011;44(2):136–147.37. Estrela C, Bueno MR, De Alencar AH, Mattar R, Valladares Neto J, Azevedo BC, et al. Method to evaluate infl ammatory root resorption by using cone beam computed tomography. J Endod 2009;35(11):1491–1497.38. Strindberg L. The dependence of the results of pulp therapy on certain factors. An analytic study based on radiographic and clinical follow-up examinations. Acta Odontol Scand 1956; 14 Suppl 21.39. Orstavik D. Reliability of the periapical index scoring system. Scand J Dent Res 1988;96(2):108–111.40. Wu MK, Shemesh H, Wesselink PR. Limitations of previously published systematic reviews evaluating the outcome of endodontic treatment. Int Endod J 2009;42(8):656–666.41. von Arx T, Janner SF, Hanni S, Bornstein MM. Agreement between 2-D and 3-D radiographic outcome

assessment one year after periapical surgery. Int Endod J 2016;49(10):915–925.42. Estrela C, Bueno MR, Azevedo BC, Azevedo JR, Pecora JD. A new periapical index based on cone beam computed tomography. J Endod 2008;34(11):1325–1331.43. von Arx T, Janner SF, Hanni S, Bornstein MM. Evaluation of new cone beam computed tomographic criteria for radiographic healing evaluation after apical surgery: Assessment of repeatability and reproducibility. J Endod 2016;42(2):236–242.44. Ee J, Fayad MI, Johnson BR. Comparison of endodontic diagnosis and treatment planning decisions using cone beam volumetric tomography versus periapical radiography. J Endod 2014;40(7):910–916.45. Mota de Almeida FJ, Knutsson K, Flygare L. The eff ect of cone beam CT (CBCT) on therapeutic decision-making in endodontics. Dentomaxillofac Radiol 2014;43(4):20130137.46. Mota de Almeida FJ, Knutsson K, Flygare L. The impact of cone beam computed tomography on the choice of endodontic diagnosis. Int Endod J 2015;48(6):564–572.

THE AUTHOR, Robert S. Roda, DDS, MS, can be reached at [email protected].


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A P R I L 2 0 1 8 249

p u l p s

AUTHOR

Paul V. Abbott, BDS, MDS , is a professor of clinical dentistry at The University of Western Australia. He is a specialist endodontist and also works part time in a private specialist endodontic practice.Confl ict of Interest Disclosure: None reported.

Can We Regrow Pulps?Paul V. Abbott, BDS, MDS

A B S T R AC T Interest in regrowing pulps is increasing. Case reports and studies have been published but predictable protocols have not been developed. While periapical healing is predictable because of canal disinfection, clinical fi ndings are variable especially regarding root maturation. Histological studies demonstrate connective tissue and blood vessels rather than pulp and dentin-like or cementum-like tissue but not dentin or cementum. Repair procedures can help retain teeth but currently have no advantages over apexifi cation and apical barrier techniques.

In recent years, dentists have become excited by the prospect of regrowing pulps after they have become necrotic and infected. This possible new treatment modality became popular

following two case reports in the early 2000s that described management of immature mandibular second premolars with infected root canal systems and chronic apical abscesses where a dens evaginatus fractured and exposed the pulp.1,2 Both cases were managed by disinfecting the root canal system prior to placing a material in the coronal part of the canal without a root canal fi lling to allow tissue to grow into the remaining canal space. Radiographs showed periapical healing and hard tissue within the canals. In one case,1

root formation appeared to progress normally with a narrow apical foramen after 30 months while the other case2

had considerable narrowing of the canal but not complete narrowing of the apical foramen after 24 months. The premise

was that some viable pulp remained in the apical part of the canal and this recovered1 or new tissue grew in from the periapical region with the aid of a blood clot scaffold inside the canal.2

This concept was not new when these cases were treated. The earliest reports of attempts to regrow the pulp date back to 1961 when Nygaard-Östby histologically analyzed cases and reported that pulps and dentin were not reliably induced.3 Later, Hørsted and Nygaard-Östby reported that when canals were intentionally fi lled 2-4 mm short of the apical foramen, slightly infl amed connective tissue formed within two months. After six and 10 months, there was a cell-rich fi brous tissue with a few lymphocytes, but it was not pulp.4

With the progress of stem cell research in the last two decades, the desire to regrow pulps has resurfaced. The purpose of this paper is to summarize the literature and provide a balanced view of the possible treatment modalities for infected immature teeth.


250 A P R I L 2 01 8

Defi nitionsBefore reviewing the literature,

the terminology needs to be defi ned. Unfortunately, the profession has adopted terms that are ill defi ned and hence are not always used appropriately. It is essential that new terms or new procedures be clearly defi ned so all practitioners and authors understand them. The use of inappropriate terminology leads to misunderstanding and potentially inappropriate clinical procedures. It

also leads to unrealistic expectations among practitioners and/or patients.

Regeneration — This term has become popular to the extent that it is almost used exclusively (although in varying forms — such as regeneration, regenerative endodontic procedures, etc.) when discussing procedures that attempt to regrow pulps. However, it has not been adequately defi ned. “Regeneration” when used in a biological sense means “restoration or new growth by an organism of organs,

p u l p s


FIGURE 1D.

FIGURE 1E .

FIGURE 1C .

FIGURES 1. Maxillary left lateral incisor in a 9-year-old girl where revascularization occurred after avulsion. It was placed in milk, then replanted and splinted 45 minutes later. After replantation (1A). Three-month review (1B). It responded to electric pulp testing but not a cold test. Seven-month review — further root development and pulp canal calcifi cation are evident. It still responded to electric pulp testing (1C). Fourteen-month review showing further pulp canal calcifi cation (1D–1E). The tooth continued to respond to electric testing.

Healing of periapical tissues

? Hard tissue — dentine-like/cementum-like/bone-like

? Nil? Connective tissue/? fi brous tissue

Cervical barrier — MTA/bioceramic

Restoration in the access cavity

FIGURE 2. Diagrammatic representation of typical fi ndings following repair procedures to treat infected immature teeth. These involve inducing a scaff old within the canal to encourage tissue ingrowth from the periapical region. The reparative tissue may be various types of soft or hard tissues or the canal may remain empty.

tissues, etc., that have been lost, removed or injured.”5 This implies that new tissue in the canal must be pulp and not other tissues. As outlined below, this does not predictably occur in animal studies or in the few human cases where histological analysis has been performed. Hence, use of this term should be abandoned until it can be proven that pulp is actually, and reliably, formed. Interestingly, the term “regeneration” was not used in the titles of the early papers; instead “revascularization” was used.1,2


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Revascularization — means “re-establishment of blood supply to a part or organ.”6 The American Association of Endodontists (AAE) defi nes it as “the restoration of blood supply.”7 This is known to occur after trauma where the pulp’s neurovascular supply is severed by luxation or avulsion. In immature teeth where the apical foramen is “open” — especially more than 1.1 mm — blood vessels can anastomose and re-establish blood supply to the pulp.8 Provided

there is no bacterial contamination, pulps can recover and function normally. Pulp canal calcifi cation typically occurs (FIGURE 1) but this is a normal physiological response demonstrating pulp survival and normal function.

Revitalization — means “to give new life to or to give new vitality or vigor to.”9 It is not defi ned in the AAE Glossary of Endodontic Terms. In dentistry, vitality refers to presence of pulp blood supply. It is a poorly understood and misused

term. In clinical practice, it is impossible to determine whether pulps have viable blood supply because thermal and electric pulp tests are sensibility tests and not vitality tests — that is, they indicate the ability of the pulp to respond to a stimulus. Specifi c tests for blood supply (laser Doppler fl owmetry or pulse oximetry) are required if claims about vitality are to be made, but these tests are not typically used in practice due to cost, time, lack of reliability and little research.

FIGURES 3 . Traumatized immature tooth with a pulpless, infected root canal system and a chronic apical abscess treated with a repair procedure. Triple antibiotic paste was used followed by Ca(OH)2 and induction of a blood clot. Preoperative (3A–B). Postoperative with an MTA cervical barrier (3C). Eighteen months (3D–E). Six years (3F). (Courtesy Dr. Eugene Chen)

FIGURE 3A .

FIGURE 3D.

FIGURE 3B .

FIGURE 3E .

FIGURE 3C .

FIGURE 3F.


252 A P R I L 2 01 8

Repair — this term can have several meanings, including “to restore to a good or sound condition after decay or damage, to restore or renew by any process of making good, strengthening, etc., to remedy and to make good.”10 This defi nition is appropriate for procedures where clinicians treat root canal infections and attempt to encourage pulp regrowth. By using this term, the profession recognizes that a reliable pulp regenerative procedure has yet to be developed (and proven) and that healing with other tissue may occur (FIGURES 2 and 3). Hence, this term will be used in this review.

Apexifi cation — the AAE defi nes this term as “a method to induce a calcifi ed barrier in a root with an open apex.”7 This usually involves placing intracanal medicaments such as calcium hydroxide to induce closure of the open apical foramen with a natural hard tissue barrier (FIGURES 4 and 5). This procedure has been used in dentistry for many years with great success and high predictability.11–14

Apical barrier technique — the AAE defi nes this as “blockage of the apical foramen; may be an induced hard tissue or artifi cial materials.”7 Placing hard-setting materials such as mineral trioxide aggregate (MTA) or other bioceramic materials prior to fi lling the remaining canal is an example of an apical barrier technique (FIGURES 6 and 7). The barrier formed is artifi cial although a natural hard tissue barrier may form later — however this cannot usually be assessed radiographically because of the radiopacity of the barrier material.

Literature OverviewNygaard-Östby was the fi rst to

investigate whether pulp could regrow after infection of the root canal system but he was unable to predictability induce pulp regrowth.3 Subsequently numerous case reports and research papers have discussed

this concept using modern approaches, especially with a focus on stem cells that may be in the periapical tissues.

Iwaya et al. assumed that some viable tissue remained in the apical part of the root canal.1 This assumption was based on the patient having pain when instruments were used in the canal. The authors stated that visual inspection confi rmed the presence of pulp tissue approximately 5 mm apical to the canal orifi ce. They therefore avoided further instrumentation to preserve this tissue, and they postulated that it recovered, regrew and continued to function by producing dentin to complete the root development.

Banchs and Trope took a different approach.2 Following canal disinfection, periapical bleeding was induced to form a blood clot in the canal to act as a “scaffold” for ingrowth of new tissue. They hypothesized that this was “similar to necrotic pulp after a traumatic injury” in immature teeth where revascularization occurs. A triple antibiotic paste was used as the main disinfecting agent. This paste was based on an in vitro study that reported it to be highly effective for infected root dentin.15

Many case reports and studies have now been published. On reviewing the case reports, it is apparent that there is no standard protocol and the types of cases vary considerably. There is no consensus regarding the materials used for canal disinfection, the timing and number of appointments, the use of adjunctive agents (such as blood products) and other variables to treat a range of presenting conditions. Reports have concerned dens evaginatus in mandibular premolars or traumatized maxillary incisors. Some cases have had draining sinus tracts indicating chronic apical abscesses, while others have had chronic apical periodontitis, acute apical abscesses or acute apical periodontitis. Each of

these is a distinctly different condition (albeit with a similar cause) so they may have different responses to treatment. The stage of root development (apical foramen width, canal width, root length) varies considerably as do the methods and criteria used to assess outcomes. As a result of these variables and the lack of standardization/consensus, the fi ndings are quite variable, which leaves the profession without true indications for when repair procedures are indicated and how to predictably perform them.

A systematic review16 found 214 studies regarding repair procedures but only six satisfi ed the inclusion criteria — English, performed in humans with fi ve or more teeth, immature infected permanent teeth. Various outcome measures were used in these six studies, including tooth survival and function, resolution of signs of disease and success/failure. Two of the six studies were excluded from parts of the analysis due to discrepancies in their initial assessments. Hence, only four studies could be assessed for all criteria, which demonstrates the limited evidence available and highlights the wide variation between studies. The four studies included only 75 teeth treated with repair procedures and 53 treated by apexifi cation or apical barrier techniques.

p u l p s

Root canal fi lling — gutta percha and cement


Healing of periapical tissues

“Natural” induced hard tissue barrier

FIGURE 4 . Diagrammatic representation of typical fi ndings following apexifi cation of infected immature teeth where an apical hard tissue barrier is induced before root fi lling.


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FIGURE 5A .

FIGURE 5C .

FIGURE 5B .

FIGURE 5D.

FIGURES 5. An immature tooth with a pulpless, infected root canal system and secondary acute apical periodontitis treated by apexifi cation with three monthly calcium hydroxide dressings. The apical hard tissue barrier was noted after 12 months. Preoperative radiograph (5A). After nine months — periapical healing and hard tissue barrier formation are evident (5B). Root canal fi lling 12 months after commencement of treatment (5C). Five-year review (5D).

Unfortunately, the data for these latter two procedures were combined, which is inappropriate because they are different clinical procedures. Each procedure cannot be assessed individually as the results of one may (positively or negatively) infl uence results of the other procedure. Tooth survival was 98.6 percent for repair procedures and 88.6 percent for combined apexifi cation/barrier techniques. The combined clinical success from two studies was 89.7 percent for repair and

100 percent for apexifi cation/barrier techniques. Periapical healing based on radiographs from three studies was 89.7 percent for repair and 100 percent for apexifi cation/barrier techniques. One study assessed bone density and found no difference among these procedures.

Quantitative analysis of changes in root length and dentin thickness have been performed. Jeeruphan et al. reported average increases of 14.9 percent and 28.2 percent in length and thickness,

respectively.17 These were compared with changes following apexifi cation and barrier techniques but only the length changes should be compared because dentin thickness cannot possibly change with apexifi cation and apical barrier techniques. After apexifi cation, average root length increased by 6.1 percent.17 Another study found average changes following repair procedures were 5 percent for root length and 21 percent for dentin thickness.18 These changes were only detectable and quantifi ed by computer software and could not be detected by visual examination of radiographs.18

Alobaid et al. reported no statistical differences for changes in root length and dentin thickness following repair and apexifi cation/apical barrier procedures.19 They used 20 percent as a clinically meaningful change for each category but only four repair cases and one apexifi cation/apical barrier case met this threshold. Hence, the clinical relevance of these changes is doubtful. The authors concluded that repair and apexifi cation/apical barrier techniques were equivalent with insuffi cient evidence to claim superiority of any technique.

In another systematic review of repair procedures,20 the authors reported that the tooth survival rates and resolution of periapical radiolucencies were excellent. However, they also reported that apical closure and continued root development were inconsistent in the reviewed studies. Furthermore, they commented that there are few well-reported randomized prospective clinical studies, plus evidence regarding long-term outcomes and late effects was sparse. No study evaluated health economic outcomes and whether there were any improvements to quality of life for the patients. Their conclusions stated that there are many gaps in the profession’s knowledge regarding repair procedures and the published evidence


254 A P R I L 2 01 8

does not provide defi nitive conclusions regarding the predictability of treatment outcomes following repair procedures.

Alobaid et al. compared outcomes and “adverse events” following repair and apexifi cation/apical barrier procedures.19 Follow-up periods were short and the number of teeth was small — 19 teeth for 15 months average in the repair group and 12 teeth for 22 months average in the apexifi cation/apical barrier group. One tooth from the repair group did not survive (further trauma) and four teeth had unfavorable outcomes (78 percent clinical success). In the other group, all teeth survived with favorable outcomes (100 percent clinical success). There were more adverse events in the repair group (eight teeth, 42 percent) than the other group (one tooth, 8 percent). The adverse event in the latter group was further trauma whereas the repair group had a variety of adverse events, including reinfection (three teeth), staining (two), fracture (one), pain (one) and further trauma (one). Some adverse events are unavoidable and/or unrelated to the procedure (e.g., further trauma, fracture) so they are not “negative” issues or contraindications. However, other adverse events (e.g., continued infection, pain, no healing) may be related to the procedure and must be considered whenever contemplating such procedures. Patients (and parents) must be informed of these possible problems.

When assessing new techniques, case reports and clinical studies have severe limitations because of the variations in techniques and conditions being treated. Hence, animal studies are extremely valuable because histology and scanning electron microscopy can be used to assess healing responses, the type/nature of reparative tissue (if any) and treatment outcomes. Animal studies can show progress of healing

over time by examining animals at appropriate time intervals. They show tissue responses within both the canals and the periradicular tissues. Histological studies can rarely be performed on human teeth. If they can, it is usually due to an adverse event that led to tooth extraction so the fi ndings may not be applicable to all cases. In addition, histological examination of extracted teeth does not usually include the periradicular tissues and it is an examination at a single time point without showing healing over time. Hence, histological animal studies are essential to provide evidence to support (or not support) new techniques.

A systematic review of repair procedures in animals where histology was used to assess tissue responses initially identifi ed 123 studies but only 13 met the inclusion criteria.21 None of these studies identifi ed pulp tissue in the canals — instead, there were varying degrees of connective tissue, fi broblast-like cells and blood vessels. Various types of hard tissue were found in the canals and none of the studies reported them as being dentin, bone, periodontal ligament or cementum — instead, they were “like” tissues suggesting similarity but not replication of these tissues. Dentin-like tissue was reported on canal walls in 4 percent of teeth after blood-clot scaffold procedures and 2 percent of teeth where blood clots plus additional materials were used. Periodontal ligament-like tissue was reported in 46 percent of teeth. Cementum-like tissue was in 64 percent of teeth with blood-clot scaffolds, 80 percent with blood clots and additional materials, 50 percent with alternative scaffold materials and only 5 percent when canals were left empty. Bone-like hard tissue was reported in 10 percent of cases with blood-clot scaffolds, 2 percent with blood clots and additional materials and 4 percent with alternative scaffold

materials. The overall conclusion of this review was: “None of the regenerative protocols resulted in predictable formation of a true pulp-dentin complex.” This is a very important fi nding that contradicts claims in many reports of pulp regeneration, revascularization or revitalization. Furthermore, claims of root strengthening need reconsideration in light of this review because a “like tissue” is unlikely to have the same physical properties as the tissue it is replacing. It will not necessarily provide the same structural strength as the original tissue. In addition, different types of “like tissues” that would not normally be present in the canal (e.g., bone-like, cementum-like) are less likely to provide strength because strength relies on having suffi cient dentin.

Some further observations from the literature,1,2,16–23 especially case reports, are:

■ Infected immature mandibular premolars with dens evaginatus generally respond well to repair procedures. Radiographs suggest resumption of normal root development, indicating that pulps may have regrown. Radiographs usually show good periradicular repair, reformation of normal periodontal ligament space, root canal narrowing and closure of

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Root canal fi lling — gutta percha and cement


Healing of the periapical tissues

Apical barrier — with MTA/bioceramic

FIGURE 6 . Diagrammatic representation of typical fi ndings following apical barrier techniques to treat infected immature teeth. A cement is placed to close the apical foramen prior to root canal fi lling.


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open apical foramina. However, caution is necessary as radiographs do not allow differentiation between dentin and other hard tissue and the tissue within the canal cannot be seen to determine its composition.

■ Maxillary incisors that become infected following trauma do not respond as predictably as mandibular premolars discussed above. Damage to the periapical stem cell base during trauma is the likely explanation. The type of trauma is probably critical because some injuries damage periapical tissues more than others — for example, crown fractured teeth may have no damage while luxated and avulsed teeth have considerable damage.

■ Controlled placement of the cervical barrier is diffi cult and radiographs often show the material placed well into the

root canal rather than just in the cervical region (FIGURE 8). In some cases, material has been placed almost to the apical foramen, which leaves little space for repair and hard tissue formation — this is more akin to apexogenesis or an apical barrier technique.

■ Follow-up radiographs usually show periapical tissue repair. This should be an expected outcome if the root canal system is adequately disinfected. It is well-known that periapical radiolucencies can heal without canals being fi lled.24,25 However, many authors use this as the sole criterion to claim pulp has “regenerated,”

even without canal and apical foramen narrowing. These fi ndings indicate periapical healing but not pulp repair/regeneration.

■ Some cases have used radiographs to assess outcomes while others have used cone beam computed tomography (CBCT). Neither of these can determine the nature of the soft tissue (if any) that may form within the canal. These images only show hard tissue changes and not presence (or absence) of soft tissue. They cannot be used to distinguish between pulp, connective tissue, fi brous tissue or other soft tissue.

■ Radiographs and CBCT cannot be used to determine the nature of new


FIGURE 7D.

FIGURE 7C .

FIGURE 7E .

FIGURES 7. Immature tooth with a pulpless, infected root canal system and chronic apical periodontitis treated with an MTA apical barrier technique. On referral to an endodontist — treatment had been commenced by a general dentist (7A). MTA apical barrier (7B). Canal fi lled with gutta percha and cement (7C). Six months (7D). Four years (7E).


256 A P R I L 2 01 8

hard tissue. This may be dentin, cementum, bone or a mixture of these. Animal studies have shown the new hard tissues are “like” these original tissues but they are not the same when examined histologically. Radiographs and CBCT images are not discriminating enough to distinguish between these different hard tissues.

■ Many clinicians report diffi culty in inducing bleeding into the canal to create a scaffold. In such cases, hard tissue does not appear to form within the canal although periradicular healing still occurs because the canal has been disinfected.

DiscussionThe literature suggests many teeth

can be retained with repair procedures. However, histological studies do not support the concept of pulp and dentin regeneration. Hence, the profession needs to reconsider what it is trying to achieve with these procedures. If the intent is to retain teeth, then repair procedures can be performed but the evidence does not show any advantages over apexifi cation and its derivative, the apical barrier technique. There are further aspects that need consideration other than just periapical healing and whether pulp and/or hard tissue form in the canal.

Periapical healing following treatment of infected root canal systems is predictable provided adequate disinfection protocols are followed.24,25 These include using a rubber dam, thorough instrumentation, antibacterial irrigants and medicaments, plus adequate tooth restoration during and after root canal treatment. Studies have shown that it is not necessary to fi ll canals with materials such as gutta percha and cement to achieve periapical

healing.24,25 In these two studies, one group of infected teeth had root canal fi llings placed while canals in another group were left empty. Periapical healing rates were identical for both groups in both studies. This clearly indicated that disinfection is the most important contributor to periapical healing. This approach should be identical for immature teeth, although instrumentation of canal walls is minimized to preserve dentin. Advocates for repair procedures employ disinfection methods although protocols vary between studies and cases. Typically, antibiotics (triple, double or single antibiotic pastes), calcium hydroxide or other antiseptics are used. These, along with canal irrigation (typically with sodium hypochlorite and ethylenediamine tetra-acetic acid), are very predictable in achieving bacteria-free root canal systems and therefore periapical healing should be expected. Hence, periapical healing following repair procedures is neither surprising nor remarkable.

Further consideration is needed regarding the aims of repair procedures. One aim is to strengthen tooth roots by regrowing pulp that can then produce dentin. This is based on Cvek’s fi ndings of cervical root fractures in some teeth after calcium hydroxide apexifi cation.26 The fractures usually occurred after further trauma (FIGURE 9) although some may

result from normal functional loading (especially in very immature teeth). The proportion of fractures was highest (77 percent) in the most immature teeth — i.e., Stage 1 development — and lowest in mature teeth (28 percent). The frequency of fractures was also highly statistically signifi cantly related to external infl ammatory resorption defects where tooth structure had been lost.26 Unfortunately, Cvek’s data has been misrepresented by proponents of repair procedures who claim fractures are very likely after apexifi cation because some publications suggest calcium hydroxide weakens dentin.27,28 However, the methods used do not replicate the clinical scenario of trauma as they typically use dentin samples rather than intact human teeth. In addition, the medicament is not just applied within the root canal and continuous loading is used rather than impact forces. Other studies have contradicted these fi ndings, suggesting that calcium hydroxide may not be the cause of dentin changes.29,30 In a systematic review regarding nonsetting calcium hydroxide, no clinical studies directly supporting a correlation between calcium hydroxide intracanal dressings and root fracture could be found in the literature. This was despite most of the in vitro studies showing some reduction in the mechanical properties of dentin

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FIGURE 8 . In repair cases, the cervical barrier placement is diffi cult to control. It may inadvertently be positioned too apical as in this immature mandibular premolar with dens evaginatus.

FIGURE 9. Cervical root fracture after apexifi cation. This tooth had three episodes of trauma after the root fi lling was completed, with the fi nal episode (three years later) resulting in fracture.


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after exposure to calcium hydroxide for fi ve weeks or longer. However, conversely, there was no conclusive data concerning calcium hydroxide used for one month or less had a negative effect on the properties of dentin.31 Careful analysis of Cvek’s paper indicates that fractures were directly related to the amount of tooth structure rather than the effect of calcium hydroxide since all cases had long-term application of this medicament and the only signifi cant variables were the stage of root development and the resorptive defects.26

Increases in root length and dentin thickness are of interest because it has been assumed that they provide greater strength to teeth over time. However, this is purely an assumption and no studies have investigated this. Increases are usually reported as average percentages but if quantifi ed as tooth structure, it is doubtful that they will strengthen teeth. As an example, extrapolating data from Saoud et al.18 suggests the change in root length averaged only approximately 1.0 mm while dentin thickness changed by only about 0.54 mm. Production of such

a small amount of hard tissue at the root apex seems unlikely to increase resistance to fracture at the cervical level where fractures occur. Likewise, a small increase in dentin thickness in the apical two-thirds of the root is also unlikely to increase resistance to cervical fracture. If any procedure could increase resistance to fracture, it would need to produce a signifi cant amount of dentin at the critical point where the fractures occur — that is, the cervical level. Unfortunately, current repair protocols cannot achieve this as barrier materials (MTA or a bioceramic material) are placed in the cervical part of

FIGURES 10 . Example showing how a tooth treated by apexifi cation can be re-treated. Postoperative radiograph after Ca(OH)2 apexifi cation (10A). Eight-year review (10B). Thirteen-year review (10C). Periapical radiolucency indicates an infected root canal system and chronic apical periodontitis. Working length radiograph shows the apical hard tissue barrier (10D). Postoperative radiograph with the new root fi lling (10E). Two-year review (10F).

FIGURE 10A .

FIGURE 10D.

FIGURE 10B .

FIGURE 10E .

FIGURE 10C .

FIGURE 10F.


258 A P R I L 2 01 8

the root, thus preventing dentin formation there. The material must be placed there to facilitate access cavity restoration and to avoid staining. Hence, it is impossible to overcome this fundamental problem of immature teeth being susceptible to cervical fracture using current techniques for managing immature teeth whether they be repair, apexifi cation or apical barrier techniques. Furthermore, a study similar to Cvek’s26 needs to be conducted so the incidence of root fractures following repair and apical barrier procedures can be determined and compared with Cvek’s results for apexifi cation.

Proponents of repair and apical barrier techniques often discuss the number of appointments and patient compliance as advantages over apexifi cation. However, there is little difference apart from overall time to treat the tooth. Apexifi cation studies have reported hard tissue barriers within 5.1 months (average 2.4 visits),12 7.8 months (three Ca(OH)2 dressings)13 and 9.0 months.14 The time for apical closure was signifi cantly related to size of the apical foramen — average 6.2 months when the opening was less than 2.0 mm and 11.0 months when more than 2.0 mm.13 Protocols for apical barrier and repair procedures vary between practitioners but both procedures require three to four appointments over one to three months. Hence, there is little difference in the number of appointments. Therefore, arguments regarding time and compliance are irrelevant and patients should be offered the most predictable treatment with a full discussion of the time and appointment scheduling. Well-informed patients are likely to comply in the interest of predictable outcomes.

Interestingly, although apexifi cation has lost favor among some clinicians, it remains the “fall-back” procedure for repair cases that have not healed or have become infected again, as

demonstrated by one case presented by Bukhari et al.23 Sometimes, apical barrier techniques are used.24 It is somewhat ironic that these procedures are only used as a “backup” rather than as the fi rst choice of management when they are associated with fewer complications and are generally more predictable.

The potential need for endodontic re-treatment if and when the root canal system becomes infected again should always be considered when planning treatment. This is a possibility because all teeth require a restoration after root canal treatment. Over time, restorations break down, leading to reinfection, because all restorations have a fi nite life span. Hence, clinicians and patients should be prepared for possible endodontic re-treatment. The concept of “what goes in, must come out” should be followed — that is, materials must be capable of being removed without risking damage to the tooth, particularly in immature teeth as they already lack tooth structure. Use of hard cements as apical or cervical barriers may be problematic. No reports have been published regarding barrier removal but it is likely to be diffi cult and even impossible in some cases. During removal, apical barrier materials may be extruded into the periapical tissues leading to infl ammation or foreign body reactions. If the material cannot be removed, the apical part of the canal may not be able to be disinfected, which may lead to treatment failure or the need for periapical surgery. Cervical barriers used for repair procedures may be more accessible but still diffi cult to remove without damaging the canal walls. In contrast, following apexifi cation to create natural hard tissue barriers it is relatively simple to re-treat as the gutta percha can be removed in the usual manner with solvents and fi les. The apical hard tissue barrier is usually still intact and the new root fi lling can be easily placed after canal disinfection (FIGURE 10).

ConclusionsHaving treatment procedures that

predictably lead to pulp regrowth is desirable but currently there is insuffi cient evidence to support this concept as a modality for managing infected immature teeth. The best that can be achieved with current repair procedures is periapical healing, but root maturation is unpredictable. In some cases, various types of soft and hard tissues may form in the canal. Current repair procedures show no advantage over apexifi cation and apical barrier techniques. The latter two procedures tend to be more predictable, and they provide more possibilities for longer-term retention of immature infected teeth. ■

REFERENCES

1. Iwaya S, Ikawa M, Kubota M. Revascularization of an immature permanent tooth with apical periodontitis and sinus tract. Dent Traumatol 2001;17:185–187.2. Banchs F, Trope M. Revascularization of immature permanent teeth with apical periodontitis: new treatment protocol? J Endod 2004;30:196–200.3. Nygaard-Östby B. The role of the blood clot in endodontic therapy: an experimental histological study. Acta Odontol Scand 1961;79:333–349.4. Hørsted P, Nygaard-Östby B. Tissue formation in the root canal after total pulpectomy and partial root fi lling. Oral Surg Oral Med Oral Pathol 1978; 46:275–282.5. Regeneration. www.dictionary.com/browse/regeneration?s=t.6. Revascularization. www.dictionary.com/browse/revascularization.7. American Association of Endodontists — Glossary of Endodontic Terms, 9th ed 2015.8. Kling M, Cvek M, Mejàre I. Rate and predictability of pulp revascularization in therapeutically reimplanted permanent incisors. Endod Dent Traumatol 1986;2:83–89.9. Revitalization. www.dictionary.com/browse/revitalization?s=t.10. Repair. www.dictionary.com/browse/repair?s=t.11. Rafter M. Apexifi cation: a review. Dent Traumatol 2005;21:1–8.12. Mackie IC, Hill E, Worthington HV. Comparison of two calcium hydroxide pastes used for endodontic treatment of nonvital immature incisor teeth. Endod Dent Traumatol 1994;10:88–90.13. Mackie IC. Bentley EM, Worthington HV. The closure of open apices in nonvital immature teeth. Brit Dent J 1988;165:169–173.14. Yates JA. Barrier formation time in nonvital teeth with open apices. Int Endod J 1988;2I:313–319.

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15. Hoshino E, Kurihara-Ando N, Sato I, Uematsu H, Sato M, Kota K, Iwaku M. In vitro antibacterial susceptibility of bacteria taken from infected root dentine to a mixture of ciprofl oxacin, metronidazole and minocycline. Int Endod J 1996;29:125–130.16. Kahler B, Rossi-Fedele G, Chugal N, Lin LM. An evidence-based review of the effi cacy of treatment approaches for immature permanent teeth with pulp necrosis. J Endod 2017;43:1052–1057.17. Jeeruphan T, Jantarat J, Yanpiset K, Suwannapan L, Khewsawai P, Hargreaves KM. Mahidol study 1: Comparison of radiographic and survival outcomes of immature teeth treated with either regenerative endodontic or apexifi cation methods — a retrospective study. J Endod 2012;38:1330–1336.18. Saoud TMA, Zaazou A, Nabil A, Moussa S, Lin LM, Gibbs JL. Clinical and radiographic outcomes of traumatized immature permanent necrotic teeth after revascularization/revitalization therapy. J Endod 2014;40:1946–1952.19. Alobaid AS, Cortes LM, LO J, Nguyen TT, Albert J, Abu-Melha AS, LIN LM, Gibbs JL. Radiographic and clinical outcomes of the treatment of immature permanent teeth by revascularization or apexifi cation: A pilot retrospective cohort

study. J Endod 2014;40:1063–1070.20. Tong HJ, Rajan S, Bhujel N, Kang J, Duggal M, Nazzal H. Regenerative endodontic therapy in the management of non-vital immature permanent teeth: a systematic review-outcome evaluation and meta-analysis. J Endod 2017;43:1453–1464.21. Altaii M, Richards L, Rossi-Fedele G. Histological assessment of regenerative endodontic treatment in animal studies with diff erent scaff olds: A systematic review. Dent Traumatol. 2017;33:235–244.22. Klevant FJ, Eggink CO. The eff ect of canal preparation on periapical disease. Int Endod J 1983;16:68–75.23. Sabeti MA, Nekofar M, Motahhary P, Ghandi M, Simon JH. Healing of apical periodontitis after endodontic treatment with and without obturation in dogs. J Endod 2006;32:628–633.24. Cvek M. Prognosis of luxated nonvital maxillary incisors treated with calcium hydroxide and fi lled with gutta percha. Endod Dent Traumatol 1992;8:45–55.25. Rosenberg B, Murray PE, Namerow K. The eff ect of calcium hydroxide root fi lling on dentin fracture strength. Dent Traumatol 2007;23:26–29.26. White JD, Lacefi eld WR, Chavers LS, Eleazer PD. The eff ect of three commonly used endodontic materials on the strength

and hardness of root dentin. J Endod 2002;28:828–830.27. Hawkins JJ, Torabinejad M, Li Y, Retamozo B, Eff ect of three calcium hydroxide formulations on fracture resistance of dentin over time. Dent Traumatol 2015;31:380–384.28. Hatibović-Kofman S, Raimundo L, Zheng L, Chong L, Friedman M, Andreasen JO. Fracture resistance and histological fi ndings of immature teeth treated with mineral trioxide aggregate. Dent Traumatol 2008;24:272–276.29. Bukhari S, Kohli MR, Setzer F, Karabucak B. Outcome of revascularization procedure: A retrospective case series. J Endod 2016;42;1752–1759.30. Nagy MM, Tawfi k HE, Hashem AA, Abu-Seida AM. Regenerative potential of immature permanent teeth with necrotic pulps after diff erent regenerative protocols. J Endod 2014;40:192–198.31. Yassen GH, Platt JA. The eff ect of nonsetting calcium hydroxide on root fracture and mechanical properties of radicular dentine: A systematic review. Int Endod J 2013;46:112–118.

THE AUTHOR, Paul V. Abbott, BDS, MDS, can be reached at [email protected].

Tonya Lanthier became a Registered Dental Hygienist (RDH) in the Atlanta area in 1995. She quickly recognized the need for a place where dental professionals could connect and create teams that excel. By design, three babies were born - twin girls and DentalPost!

DentalPost has grown into the leading dental industry job board and community serving more than 700,000 dental professionals. We believe in using data for a

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i m p l a n t s v s . e n d o d o n t i c s

AUTHORS

Tory Silvestrin, DDS, MSD, attended the University of Washington School of Dentistry and earned his endodontic certifi cate and master of science in dentistry degree. He also earned his master of science in health professions education degree from Loma Linda University. He is the chair of the department of endodontics.Confl ict of Interest Disclosure: None reported.

Implant Dentistry and Endodontics: Can There Be a Mutually Benefi cial Relationship?Tory Silvestrin, DDS, MSD, and Charles J. Goodacre, DDS, MSD

A B S T R AC T Endodontics focuses on preservation of teeth with pulpal and periapical disease. Implant dentistry provides replacement of missing or nonsalvageable teeth with implant-supported restorations. Arguments have been made that teeth are sometimes treated endodontically but instead should be replaced with implants. Opposing arguments suggest that teeth have been needlessly replaced with implants. Data show that endodontics and implant dentistry play important roles in patient-centered dentistry.

Charles J. Goodacre, DDS, MSD, graduated with a doctor of dental surgery degree in 1971 and subsequently earned a master of science in dentistry degree in prosthodontics. He served as dean of the Loma Linda University School of Dentistry from 1994–2013 and now serves as a distinguished professor of prosthodontics.Confl ict of Interest Disclosure: None reported.

Endodontics as a specialty has promoted the preservation of teeth that can be properly restored and function satisfactorily after treatment of pulpal and periapical

disease. Preserving the natural dentition has been the goal of endodontics since its initiation more than 100 years ago. Where teeth are not salvageable or missing, the introduction of implant dentistry has been a very welcome addition to dental care. In patient-centered practices, treatment options should be presented objectively for the patient’s benefi t. When the popularity of dental implants was rising several decades ago, most endodontists resisted joining the move to incorporate the new treatment modality. Many were of the opinion that implants were a competitive challenge. While that notion still exists, endodontists have in recent years become increasingly interested in incorporating

implant dentistry in their practices. They have begun to recognize the value of adding this treatment modality in cases where teeth cannot be treated endodontically or have a questionable prognosis. Implants provide the benefi t that adjacent teeth do not need to be involved in replacing a nonsalvageable tooth such as in fi xed prosthodontics.1

After a period of time of confrontations between endodontists and dentists promoting dental implants, it seems that the time has come for coexistence of the two treatment entities in the interest of best patient care. In light of this, there are times when retention of a compromised tooth through endodontic and restorative intervention is the most appropriate choice in a region that would otherwise be aesthetically marginalized if a dental implant were considered.2 At other times, the retention of some teeth with root canal


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treatment could result in a compromised prognosis due to the extensive loss of tooth structure or an aesthetic compromise when adjunctive treatments such as crown lengthening or orthodontic extrusions are required to restore the tooth.

History of Implant DentistryDental implants have a history that

precedes Brånemark’s introduction of osseointegration. There is evidence of prehistoric people attempting to adapt and use foreign materials to replace missing dentition.3,4 These early attempts included replacement of teeth with wood, bone, ivory, gold and other materials. Early Egyptian and South American cultures used cobalt alloy, tantalum, stainless steel and iridium.5

In the 1970s, physician Per-Ingvar Brånemark introduced the concept of osseointegration (the physical contact of bone to titanium) of dental implants.6 Brånemark had previously discovered — serendipitously in another experiment — favorable soft and bony tissue reactions to titanium.

The Brånemark protocol involved placing implants into the alveolar process and then covering it with the soft tissue fl ap raised to expose the bone. Then, following three to six months of healing, the implants would be uncovered and used for support and retention of a prosthesis.7

Before the Brånemark root-formed implants were introduced, another form of implant had gained some popularity: endodontic implants. These were implants developed for the purpose of retaining poorly supported teeth.8 These implants were rigid (usually composed of titanium) and extended through the root apex into the apical bone to stabilize teeth with weakened periodontal support. Other applications for endodontic implants were stabilization of overdenture abutment teeth9 and teeth with root fractures10 and replanted avulsed and

autotransplanted teeth.11–14 The use of endodontic implants for root fractures where the apical segment of the tooth is removed is no longer recommended.15

The placement of endodontic implants gained some popularity from the mid-1960s to early 1970s.8 The popularity faded when the outcomes became unpredictable and apical lesions were often associated with the implants.16

Despite the problems with apical lesions, these implants did solve the excess mobility of teeth that would otherwise need to be extracted. An advantage in using endodontic implants was that

in mandibular incisors the stress from mobile teeth was shifted from the thin buccal bone to the thicker lingual bone.17 While the use of endodontic implants is rare today, it is interesting to look back and recognize the role endodontists had in the concept of implant dentistry long before the advent of contemporary endosseous root-form implants.

Endodontists and Dental ImplantsDespite a history of involvement with

endodontic implants, endodontists did not get involved with root-form implants early on. Many endodontists viewed the new innovation with some suspicion and certainly with very little enthusiasm. Some endodontists, however, were curious enough to try the new implant method and because endodontic implant

placement was a part of the specialty scope, it was considered to be within the practice scope of endodontists to also place endosseous implants. The Commission on Dental Education (CODA) modifi ed the Standards for Advanced Specialty Education Programs in Endodontics in the early 1990s to include endosseous implants, thus including this new surgical procedure in the endodontists’ scope of practice.18 Prior to the introduction of this standard, the CODA Standards in 1985 stated that graduate students should provide service and demonstrate experience with endodontic implants.19 Currently, dental implants are included to varying degrees in all advanced endodontic education programs and thus endodontists may include them in their practices.

The American Association of Endodontists (AAE) has recognized the role implants play in the specialty of endodontics and have incorporated curricula in its annual sessions to educate endodontists about treatment planning, problem solving and surgical aspects of the placement of dental implants in practice.

Loma Linda University was a pioneer in the integration of endodontics and dental implants with the establishment of a program track in the advanced endodontic program that would include an additional year of surgical implant training. An advantage to including implant dentistry in the endodontic program is the opportunity for a patient with a nonsalvageable tooth to have it replaced with an implant without the need to be referred to another clinic. The patient may have been referred to the endodontic clinic for evaluation of a tooth with a problem that turns out to be a root fracture, for instance; such a patient could receive both a thorough endodontic evaluation along with information about treatment options that could include a dental implant. With the approval of the referring dentist, the fractured tooth could

It seems that the time has come for coexistence of the two treatment entities in the interest of best patient care.


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versus 36 percent opposing. Sixty-seven percent of respondents reported feeling endodontics has been negatively affected by the growth of implant dentistry; 33 percent did not feel that way. Implant dentistry has become a part of many endodontic practices in California; however, the opinions on the value of including implant dentistry in practices is split and many endodontists still feel that they have to compete with dentists who place implants in patients who could benefi t from endodontic treatment.

In addition to the above considerations, some referring dentists may feel that endodontists lack training in prosthetic reconstruction and soft tissue management — skills that are necessary to properly diagnose and place dental implants. Thus they may hesitate to refer their patients to endodontists for such a service. From the endodontists’ point of view, their experience in microsurgical procedures involving root-end isthmuses, manipulating neurovascular bundles and managing the maxillary sinuses equip them with both knowledge of anatomy and surgical skills. Such skills and knowledge can be employed by endodontists to precisely place dental implants in restoratively driven anatomic positions.

Implant Dentistry and Endodontics Compared: Patient-Centric Factors

Endodontics has long been perceived by patients as being associated with pain and fear, but the evidence from the literature shows that pain is not often associated with endodontic treatment and root canal treatment actually substantially reduces pain (50 to 75 percent) compared to preoperative levels.26–28 It is often the preoperative pain that the patients retrospectively associate with perceived postoperative pain, and it has been shown that postoperative discomfort

be replaced with an implant and returned to the referring dentist for the prosthesis.

Endodontists who offer dental implants as a treatment option to their patients are in a good position to present patients with clinical information about advantages and disadvantages of competing options as may occur in certain circumstances. A maxillary molar with a compromised buccal root but with minimal bone support may be better treated with a root amputation rather than replacement with an implant; conversely, a mandibular molar with a vertical fracture of one root may not be as suitable for root amputation.

Endodontists Placing Implants and Its Acceptance by Referring Dentists

Endodontists interested in including implant dentistry in their practices must show their referring colleagues that there is patient-centered value in the practice of implant dentistry by endodontists. Expertise in surgical placement of implants allows endodontists to offer patients that service if indicated. This can save patients time in reducing the number of visits to various dental providers. It may also reduce the number of surgical procedures. If surgical exposure of a root is needed to determine presence of a fracture, the extraction of a tooth with fracture could be accomplished at the same time.20 In addition to more effi cient patient management avoiding a second surgical procedure to remove the tooth, it may also help preserve the bony housing. And there is evidence that placement of an immediate implant following extraction helps to minimize bone loss.21,22 Bone loss cannot be completely eliminated and bone remodeling and soft tissue changes will usually occur.23

Benefi cence — a core ethical pillar in dentistry — is demonstrated fully when an unbiased provider can clearly and knowledgably discuss and offer both endodontic and dental

implant information and treatments if accepted by the patient. Endodontics and implant dentistry can not only coexist, but also must coexist for the benefi t of patients. Endodontic treatment and implant placement are uniquely positioned to challenge each other, contradict each other and ultimately perfectly complement each other.

In a recent survey, the majority of general dentists polled reported unfavorable attitudes regarding endodontists placing dental implants.24 Sixty-six percent of respondents opposed

endodontists placing implants, and 73 percent indicated they would not refer patients to an endodontist for implant placement. It is no surprise that these responses are in opposition to a survey of endodontists regarding their thoughts on implant placement.25 In the latter survey, 57 percent of respondents supported endodontists placing implants with 5.7 percent of responding endodontists reporting they currently place implants.

In an ongoing survey by the authors of California endodontists, 18 percent of respondents report currently placing dental implants versus 82 percent who do not. Approximately 25 percent of the state endodontists have responded so far. Of those, 64 percent indicated that they believe implant dentistry should continue to be a part of the scope of endodontics


It has been shown that postoperative discomfort related to root canal treatment and surgical implant placement is equal.


A P R I L 2 0 1 8 263

related to root canal treatment and surgical implant placement is equal.29–31

Financial concerns about dental treatment are important to patients. Nonsurgical root canal treatment and a prosthetic crown compare favorably to a comparable implant/crown treatment.29,32,33 Other options such as fi xed partial dentures are also available at comparable cost.34

A concern that patients often have is treatment time. When comparing endodontic treatment versus treatment involving dental implants, the latter requires signifi cantly more time than the former.35 Patients experience more inconvenience due to the increased treatment time of a two-stage implant versus having a root canal-treated tooth back in function much more quickly. Even immediate placement with provisionalization requires a second appointment after healing to provide the defi nitive crown.

Postoperative complications occur more commonly with dental implants (screw loosening being the most common complication) than with endodontic treatment and this both adds to increased patient inconvenience and patient cost.36 The incidence of postoperative complications rises to approximately 20 percent and can range from the need to retighten the abutment screw to refabricating the crown.35 Others have found that the three-year complication rate with implants rises to 72 percent, but the implant-supported crowns in this particular study were acrylic resin fused-to-metal crowns, which are not widely used due to the higher complication rate.37 Despite the range reported in the literature, there is consensus that implant-supported crowns have a higher incidence of complications than root canal-treated teeth.38

In terms of biomechanical considerations, implants have been found to provide a signifi cantly lower maximum biting force, reduced chewing effi ciency and smaller occlusal contacts compared to root canal-treated teeth.39

Implant placement has been shown to increase patient quality of life measures, but this is more signifi cantly pronounced when implants are used to anchor a removable partial denture (thus replacing multiple missing teeth) than when an implant is used for single tooth replacement. The majority of

patients report some satisfaction or high satisfaction with both endodontic treatment and single tooth implants. In addition, endodontic treatment has been determined to signifi cantly improve the quality of life for patients.26,40

Prior to including aesthetics in the success criteria, poor aesthetics, implant malposition, soft tissue recession, bone maintenance and unfavorable soft tissue confi guration were not considered when evaluating implant success.41 It is important to consider aesthetics when judging implants to be a success or failure, as aesthetic problems outnumber mechanical failures in the anterior dentition.38 Loss of dental papilla is the most common complication after implant placement and can result in black appearing triangles interproximally.42,43

Contracture of the papillae occurs in 5 to 20 percent of patients after implant placement compared to the contralateral natural teeth; retaining natural teeth with root canal treatment has been recommended to help maintain the papilla in the anterior aesthetic zone.44 Treatment planning is crucial when considering implant placement, as thin gingival biotypes are more prone to recession than are thick biotypes and some authors have advocated preservation of natural teeth in aesthetic zones when a thin periodontal biotype is present.2,33,45 Aesthetic concerns clearly favor retention of natural teeth when possible in the maxillary anterior segment.

Cost, success, treatment time, postoperative interventions, postoperative pain, biomechanical factors, patient satisfaction with treatment and aesthetics all play an intertwined role in the patient’s decision whether to elect tooth preservation or replacement with a dental implant. Clearly both treatment options offer myriad benefi ts, but they also have drawbacks that need to be fully explained to the patient.

Outcomes of Dental Implants and Endodontic Treatment

Expected outcomes of treatment options need to be presented to patients. Comparing such outcomes is, however, diffi cult.46 Part of the problem comes from differences in defi ning outcomes since both success and survival concepts have been used.46 Nevertheless, there is information available to review.

Contributing to the diffi culty in comparing outcomes between endodontic and implant treatments has been differences in success criteria, different lengths of historical data available and often less than rigorous research protocols.29 Success of root

Both treatment options off er myriad benefi ts, but they also have drawbacks that need to be fully explained to the patient.


264 A P R I L 2 01 8

canal treatment is defi ned in stages of healing versus implant healing which is binary success versus failure. This gives the appearance of less fully healed endodontic treatments than implants due to the structure of the success and failure criteria.47–52

Many publications have shown both implants and endodontic treatments

to share high levels of success, with no signifi cant difference in survival of single tooth implants or teeth with root canal treatment.29,36,53

Implant survival has been reported at very high levels, from 96 to 98.9 percent with at least a fi ve-year follow-up period.54–58 Others have reported lower survival fi gures, ranging from 82

to 88.5 percent.59,60 Success of implants at the fi ve-year period has been reported to range between 83 and 99 percent with the lower success specifi cally in the maxillary molar region.61–63

Initial and secondary (re-treatment) nonsurgical root canal treatment outcome studies have looked both at success and survival. In terms of



FIGURE 1D. FIGURE 1E . FIGURE 1F.

FIGURE 1G. FIGURE 1H. FIGURE 1I .

FIGURES 1. Treatment approaches for a mandibular fi rst molar. Radiograph taken 10 years following root canal treatment due to pulp necrosis (1A). The tooth had developed a vertical root fracture in the mesial root and was extracted. In 1994, an implant was placed, but it was not centered in the edentulous space and there was a substantial mesial cantilever to the crown (1B). There were multiple episodes of screw loosening over the following years. In 1999, a new implant was placed due to the repeated mechanical complications with the initial implant (1C). However, it also was not ideally centered in the edentulous space and there was still an extension of the crown mesial to the implant. In 2006, the implant developed peri-implant mucositis, which was managed with improved home care (1D). Additional peri-implant bone loss was noted in 2010 (1E). Due to continued bone loss, bone grafting was performed (1F). In 2016, due to increasing bone loss, the implant was removed and bone graft material placed into the osteotomy (1G). Due to the regular recurrence of complications associated with the implants, the patient elected not to have another implant and instead have a fi xed partial denture. After healing following extraction and bone grafting, a three-unit metal-ceramic fi xed partial denture was placed (1H). Periapical radiograph of the completed fi xed partial denture (1I).


A P R I L 2 0 1 8 265

survival, four-year retention has been shown to be 95 percent.64,65 Another systematic review indicated four- to fi ve-year survival of 93 percent and 87 percent survival at eight to 10 years.66 Epidemiological studies containing greater than 1 million subjects have found 93 to 97 percent survival of root canal-treated teeth (both initial and re-treatment).67,68 Others have found success rates of endodontic re-treatment to range between 85 and 96 percent.67,69,70 Some have found lower success rates during re-treatment, with success of 85.5 percent using more strict radiographic criteria.71

Endodontic microsurgery has a much higher success rate than traditional root-end surgery (94 percent versus 59 percent).72,73 However, a systematic review found that endodontic microsurgery had a lower success rate than that of single implants (98 percent versus 90 percent at a two- to four-year follow-up, respectively). Additionally, at two to four years posttreatment, single implants had higher survival rates than teeth treated with endodontic microsurgery.74 This was one of the few studies that directly compared endodontic surgery and implant survival and success.

An Evolving Change in Practice Philosophy: Is This Change in Our Patients’ Best Interest?

The success and proliferation of dental implant therapy has caused many endodontists to notice a declining patient interest in preserving their natural dentition when faced with the prospect of saving a tooth through root canal treatment versus extracting the tooth and placing a dental implant. Despite literature showing similar survival rates for root canal treated-teeth and single tooth implants, some dentists seem to consider dental implants to be the gold standard and that root canal treatment is a temporary effort to keep a tooth with endodontic disease a few more years. To the contrary, one might say there is no better “implant” than a natural tooth. After all, with proper care, teeth have been lasting the entire lifetime of many patients. Additionally, implants and their restorations are not always successful due to systemic factors and other factors such as the surgical procedure used or the implant placement location that results in unfavorable biomechanics (FIGURE 1). Likewise, not all root canal treatments are successful either due to the inability to instrument the presence of unique anatomy or the subsequent restoration procedures (FIGURE 2).

As dental implants are increasingly covered by dental insurance, the expansion of implant dentistry into the root canal treatment “market share” will likely continue to increase. Dentists also form opinions based on personal experience. A colleague of one of the authors (T.S.), who works in a remote town with no endodontists nearby, chooses to preferentially treatment plan and urge patients to consider dental implants rather than undergoing root canal treatment reasoning that “it’s faster for me to place an implant than to do a root canal … implants put more money into my wallet than do root canals.” This colleague’s opinion presents a challenge to both organized dentistry and dental education.

An alarming trend was highlighted in a recent editorial in the Journal of Dental Research. Dentists with less training who are less educated about surgical placement of dental implants (as well as prosthetic reconstruction of dental implants) more often recommended removal of teeth (as opposed to preservation of teeth via endodontic means).75 The editorial also mentions that there is a trend toward removal of teeth that are compromised but salvageable, such as teeth with periodontal disease, endodontic needs or prosthetic reconstructive needs. While dental implants may seem to be a solution to all problem teeth, the facts do not support that notion. Iqbal and Kim53 have stated that routinely choosing to place a single tooth implant for a compromised tooth that could otherwise be saved by endodontic treatment cannot be advocated in light of the sparse literature that directly compares single tooth implants and restored root canal-treated teeth. As advocated at a Consensus Conference regarding dental implants, the decision to treat a tooth with endodontics or replace with a single tooth implant should be based on criteria other than long-term outcome because the treatment modalities produce similar outcomes.76

FIGURES 2. Examples of failures due to poorly constructed prosthetic restorations of endodontically iterated teeth. The anterior fi xed partial denture failed due to the presence of a post and core in the lateral incisor abutment that was both short and too large in diameter (2A). The maxillary canine root fractured due to the presence of a large diameter post (2B). Note that the lateral incisor has a short post that also has excess diameter.

FIGURE 2A .

FIGURE 2B .


266 A P R I L 2 01 8

36. Doyle SL, Hodges JS, Pesun IJ, Law AS, Bowles WR. Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and single-tooth implants. Compend Contin Educ Dent 2007;28(6):296–301.37. Wannfors K, Smedberg JI. A prospective clinical evaluation of diff erent single-tooth restoration designs on osseointegrated implants. A three-year follow-up of Brånemark implants. Clin Oral Implants Res 1999;10(6):453–8.38. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complications with implants and implant prostheses. J Prosthet Dent 2003;90(2):121–32.39. Woodmansey KF, Ayik M, Buschang PH, White CA, He J. Diff erences in masticatory function in patients with endodontically treated teeth and single-implant-supported prostheses: A pilot study. J Endod 2009;35(1):10–4.40. DeBaz C, Hahn J, Lang L, Palomo L. Dental Implant Supported Restorations Improve Quality of Life in Osteoporotic Women. Int J Dent 2015;2015(451923).41. Salinas TJ, Eckert SE. In patients requiring single-tooth replacement, what are the outcomes of implant — as compared to tooth-supported restorations? Int J Oral Maxillofac Implants 2007;22 Suppl:71–95.42. Grunder U, Polizzi G, Goene R, Hatano N, Henry P, Jackson WJ, et al. A three-year prospective multicenter follow-up report on the immediate and delayed-immediate placement of implants. Int J Oral Maxillofac Implants 1999;14(2):210–6.43. Polizzi G, Fabbro S, Furri M, Herrmann I, Squarzoni S. Clinical application of narrow Branemark System implants for single-tooth restorations. Int J Oral Maxillofac Implants 1999;14(4):496–503.44. Chang M, Wennstrom JL, Odman P, Andersson B. Implant supported single-tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions. Clin Oral Implants Res 1999;10(3):185–94.45. Ahmad I. Anterior dental aesthetics: Gingival perspective. Br Dent J 2005;199(4):195–202.46. Torabinejad M. Apples and oranges. J Endod 2003;29(8):541–2.47. Friedman S, Mor C. The success of endodontic therapy — healing and functionality. J Calif Dent Assoc 2004;32(6):493–503.48. Orstavik D. Time-course and risk analyses of the development and healing of chronic apical periodontitis in man. Int Endod J 1996;29(3):150–5.49. Roos J, Sennerby L, Lekholm U, Jemt T, Grondahl K, Albrektsson T. A qualitative and quantitative method for evaluating implant success: A fi ve-year retrospective analysis of the Brånemark implant. Int J Oral Maxillofac Implants 1997;12(4):504–14.50. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term effi cacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1(1):11–25.51. Wennstrom JL, Ekestubbe A, Grondahl K, Karlsson S, Lindhe J. Implant-supported single-tooth restorations: A fi ve-year prospective study. J Clin Periodontol 2005;32(6):567–74.52. Smith DE, Zarb GA. Criteria for success of osseointegrated endosseous implants. J Prosthet Dent 1989;62(5):567–72.53. Iqbal MK, Kim S. A review of factors infl uencing treatment planning decisions of single-tooth implants versus

ConclusionBased on data from the literature,

it is evident that both endodontic treatment and dental implants have a place in the dental care of patients. Patient-centered dental care must include providing patients with evidence-based information about treatment options suggested. Such an approach will allow both disciplines in dentistry to coexist for the patients’ benefi t. ■

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17. Asundi A, Kishen A. Biomechanics of endodontic endosseous implants — a comparative photoelastic evaluation. Endod Dent Traumatol 1999;15(2):83–7.18. Nix JA. Commission on dental accreditation for the advanced education programs in endodontics. ADA Correspondence 1991:1–21.19. Commission on dental accreditation for the advanced education programs in endodontics. ADA Correspondence 1985:1–15.20. Lazzara RJ. Immediate implant placement into extraction sites: Surgical and restorative advantages. Int J Periodontics Restorative Dent 1989;9(5):332–43.21. Paolantonio M, Dolci M, Scarano A, d’Archivio D, di Placido G, Tumini V, et al. Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man. J Periodontol 2001;72(11):1560–71.22. Block MS, Kent JN. Placement of endosseous implants into tooth extraction sites. J Oral Maxillofac Surg 1991;49(12):1269–76.23. Kan JY, Rungcharassaeng K, Lozada J. Immediate placement and provisionalization of maxillary anterior single implants: One-year prospective study. Int J Oral Maxillofac Implants 2003;18(1):31-9.24. Crawford JF, McQuistan MR, Williamson AE, Qian F, Potter KS. Should endodontists place dental implants? A national survey of general dentists. J Endod 2011;37(10):1365–9.25. Potter KS, McQuistan MR, Williamson AE, Qian F, Damiano P. Should endodontists place implants? A survey of U.S. endodontists. J Endod 2009;35(7):966–70.26. Dugas NN, Lawrence HP, Teplitsky P, Friedman S. Quality of life and satisfaction outcomes of endodontic treatment. J Endod 2002;28(12):819–27.27. Torabinejad M, Cymerman JJ, Frankson M, Lemon RR, Maggio JD, Schilder H. Eff ectiveness of various medications on postoperative pain following complete instrumentation. J Endod 1994;20(7):345–54.28. Torabinejad M, Dorn SO, Eleazer PD, Frankson M, Jouhari B, Mullin RK, et al. Eff ectiveness of various medications on postoperative pain following root canal obturation. J Endod 1994;20(9):427–31.29. Torabinejad M, Anderson P, Bader J, Brown LJ, Chen LH, Goodacre CJ, et al. Outcomes of root canal treatment and restoration, implant-supported single crowns, fi xed partial dentures and extraction without replacement: A systematic review. J Prosthet Dent 2007;98(4):285–311.30. Hashem AA, Claff ey NM, O’Connell B. Pain and anxiety following the placement of dental implants. Int J Oral Maxillofac Implants 2006;21(6):943–50.31. Moiseiwitsch C. A cost-benefi t comparison between single tooth implant and endodontics. J Endod 2001;27:235.32. Kim SG, Solomon C. Cost-eff ectiveness of endodontic molar re-treatment compared with fi xed partial dentures and single-tooth implant alternatives. J Endod 2011;37(3):321–5.33. Christensen GJ. Implant therapy versus endodontic therapy. J Am Dent Assoc 2006;137(10):1440–3.34. Goodacre CJ, Naylor WP. Single implant and crown versus fi xed partial denture: A cost-benefi t, patient-centered analysis. Eur J Oral Implantol 2016;9 Suppl 1:S59–68.35. Creugers NH, Kreulen CM, Snoek PA, de Kanter RJ. A systematic review of single-tooth restorations supported by implants. J Dent 2000;28(4):209–17.



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techniques with and without the use of higher magnifi cation. J Endod 2012;38(1):1–10.74. Torabinejad M, Landaez M, Milan M, Sun CX, Henkin J, Al-Ardah A, et al. Tooth retention through endodontic microsurgery or tooth replacement using single implants: A systematic review of treatment outcomes. J Endod 2015;41(1):1–10.75. Giannobile WV, Lang NP. Are Dental Implants a Panacea or Should We Better Strive to Save Teeth? J Dent Res 2016;95(1):5–6.76. Iacono VJ, Cochran DL. State of the science on implant dentistry: A workshop developed using an evidence-based approach. Int J Oral Maxillofac Implants 2007;22 Suppl:7–10.

THE CORRESPONDING AUTHOR, Tory Silvestrin, DDS, MSD, can be reached at [email protected].

preserving natural teeth with nonsurgical endodontic therapy. J Endod 2008;34(5):519–29.54. Misch CE, Perel ML, Wang HL, Sammartino G, Galindo-Moreno P, Trisi P, et al. Implant success, survival and failure: The International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent 2008;17(1):5–15.55. Misch CE, Misch-Dietsh F, Silc J, Barboza E, Cianciola LJ, Kazor C. Posterior implant single-tooth replacement and status of adjacent teeth during a 10-year period: a retrospective report. J Periodontol 2008;79(12):2378–82.56. Jung RE, Pjetursson BE, Glauser R, Zembic A, Zwahlen M, Lang NP. A systematic review of the fi ve-year survival and complication rates of implant-supported single crowns. Clin Oral Implants Res 2008;19(2):119–30.57. Lindh T, Gunne J, Tillberg A, Molin M. A meta-analysis of implants in partial edentulism. Clin Oral Implants Res 1998;9(2):80–90.58. Eckert SE, Choi YG, Sanchez AR, Koka S. Comparison of dental implant systems: Quality of clinical evidence and prediction of fi ve-year survival. Int J Oral Maxillofac Implants 2005;20(3):406–15.59. Ottoni JM, Oliveira ZF, Mansini R, Cabral AM. Correlation between placement torque and survival of single-tooth implants. Int J Oral Maxillofac Implants 2005;20(5):769–76.60. Norton MR, Wilson J. Dental implants placed in extraction sites implanted with bioactive glass: human histology and clinical outcome. Int J Oral Maxillofac Implants 2002;17(2):249–57.61. Buser D, Ingimarsson S, Dula K, Lussi A, Hirt HP, Belser UC. Long-term stability of osseointegrated implants in augmented bone: A fi ve-year prospective study in partially edentulous patients. Int J Periodontics Restorative Dent 2002;22(2):109–17.62. Bornstein MM, Schmid B, Belser UC, Lussi A, Buser D. Early loading of nonsubmerged titanium implants with a sandblasted and acid-etched surface. Five-year results of a prospective study in partially edentulous patients. Clin Oral Implants Res 2005;16(6):631–8.63. Becker W, Becker BE, Alsuwyed A, Al-Mubarak S. Long-term evaluation of 282 implants in maxillary and mandibular molar positions: A prospective study. J Periodontol 1999;70(8):896–901.64. Ng YL, Mann V, Gulabivala K. A prospective study of the factors aff ecting outcomes of nonsurgical root canal treatment: Part 1: Periapical health. Int Endod J 2011;44(7):583–609.65. Ng YL, Mann V, Gulabivala K. A prospective study of the factors aff ecting outcomes of nonsurgical root canal treatment: Part 2: Tooth survival. Int Endod J 2011;44(7):610–25.66. Ng YL, Mann V, Gulabivala K. Tooth survival following nonsurgical root canal treatment: A systematic review of the literature. Int Endod J 2010;43(3):171–89.67. Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: An epidemiological study. J Endod 2004;30(12):846–50.68. Chen SC, Chueh LH, Hsiao CK, Tsai MY, Ho SC, Chiang CP. An epidemiologic study of tooth retention after nonsurgical endodontic treatment in a large population in Taiwan. J Endod 2007;33(3):226–9.

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FONTANA— GP + Real Estate!! Premier office with 50 years of goodwill. In a 3,000 sq bldg with 8 eq ops. Has the latest technology. Grossed approx. $2.3M in 2016. Net of $968K. Property ID #5140.

PALM SPRINGS – General prac ce with 3 equipped ops located in a free standing bldg. Established in 2005. Suite is approx. 1,200. Seller work 5 days/wk. BUYER’S NET OF $153K. Property ID #4487.

RANCHO CUCAMONGA— GP established in 2004 in busy shopping center. Consists of 3 eq ops in a 1,200 sq suite. Grossed $422K in 2017. Net $146K. Prop-erty ID #5169.

RIVERSIDE—GP + Real Estate!! Established in 1975 in free standing historic bldg. Has 4 eq ops in a 2,000 sq

office. Projec ng approx. $284K for 2016. Property ID #5146.

TEMECULA—Modern designed prac ce w/ 3 eq ops. Projec ng approx. $1.2M . Net of $444K. Property ID #5155.

UPLAND—Pediatric dental prac ce located in a medical bldg with 40 years of goodwill. Consists of 4 chairs in open with Alpha-Dent so ware. Grossed $271K in 2016. Property ID #5188.

COMING SOON IN PALM DESERT

SAN DIEGO COUNTY

CARLSBAD—Well established GP w/ 3 eq ops and 2 plmbd not eq near residen al are. Buyer’s net of $121K. Property ID #5191.

SAN DIEGO — Well established prac ce w/ 3 new eq ops in a 1,087 sq suite. Projec ng approx. $300K. NET $127K. Property ID #5200.

SAN DIEGO— GP in med/dent bldg. w/ 3 eq ops. Fee for service. Estab. circa 1950. Grossed $301K in 2017. Net $129K. Property ID # 5212.

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A P R I L 2 0 1 8 269

RM Matters

Spring is a prime time to deep clean your practice and tie up any loose ends from the previous year. It’s also a great opportunity to review your patient records and

ensure all fi les are accurate and current.Below are some things to consider

when revisiting patient charts. If you fi nd something is missing, review the chart with your patient at their next visit.

Does the chart have a signed treatment plan?Before beginning any dental treatment,

you should document the clinical exam fi ndings, diagnoses of the patient and your treatment recommendations. A treatment plan should include a complete overview of the treatment to be performed, how it will help your patient, alternatives available and alternatives selected, in addition to any part of the treatment requiring referral to a specialist.

Note patient expectations regarding cost of treatment, overall aesthetics and longevity of treatment. Should fi nances affect the patient’s treatment decision, the risks and consequences of delaying treatment should also be discussed and noted in the chart.

Does the chart have a signed fi nancial agreement?

For many patients, fi nances will play a signifi cant role in the treatment plan. When discussing treatment options, be sure to include the patient’s estimated dental benefi ts portion of payment and predicted out-of-pocket expenses while making it clear that the patient is ultimately responsible for all fees regardless of what their dental benefi ts cover. If a patient has concerns about paying for treatment,

Spring Cleaning Isn’t Limited to the Offi ce: Update Patient Records To Mitigate Risks

TDIC Risk Management Staff

You are not a sales goal.

You are a dentist deserving of an insurance company relentless

in its pursuit to keep you protected. At least that’s how we see

it at The Dentists Insurance Company, TDIC. Take our Risk

Management program. Be it seminars, online resources or our

Advice Line, we’re in your corner every day. With TDIC,

you are not a sales goal or a statistic. You are a dentist.

Protecting dentists. It’s all we do.®

800.733.0633 | tdicinsurance.com | CA Insurance Lic. #0652783

consider offering payment arrangements that will fi t their fi nances rather than altering the treatment plan.

Keep a signed copy of the fi nancial agreement in the chart separate from the medical history. This will help avoid mixing the patient’s protected health information (PHI) with their fi nancial information should there be a need to share fi nancial data with a third party that should not have access to the PHI, such as a collection agency.

Is the patient’s health history form current? Ideally, you should review a patient’s

health history at every appointment. Go over the previous health history form and update as needed. Be sure to clarify any unanswered questions and inquire as to any recent visits to another health care provider.

Inquire about pregnancies, surgeries, radiation therapy, trips to the emergency room or other hospitalizations. Review their current medications and note if they have begun, discontinued or changed any


270 A P R I L 2 01 8

prescribed or over-the-counter medications. Have the patient sign and date the health history form and all subsequent updates.

If you are concerned about treating a patient with underlying health issues, you can obtain medical consultation with their primary care physician before proceeding. Keep the physician’s response in the patient’s fi le and follow their recommendations to ensure patient safety.

Is the patient chart inactive? While there are no statutory

requirements, The Dentists Insurance Company (TDIC) recommends that you keep patient charts for a minimum of

10 years after the last date the patient is seen, if not indefi nitely. For patients who are minors, you should retain their chart for 10 years from their last treatment or seven years past age 18. If you decide to dispose of inactive patient charts, it is imperative that you do so in a way that is consistent with HIPPA regulations.

In one case reported to TDIC’s Risk Management Advice Line, a dentist was seeking to shred outdated patient information. He canceled his prior contract with a licensed and bonded shredding company and hired a “friend of a friend” who promised to shred the confi dential records at a reduced rate.

The dentist paid the individual $200 to shred the fi les without having signed an associate agreement. The dentist became concerned when he did not receive a shredding confi rmation. Ultimately, he realized that he might never hear from him. The dentist also understood the potential for a claim of unauthorized disclosure of PHI should these patient records be discovered intact. The Risk Management analyst suggested ways to avoid such problems in the future and recommended reporting the matter to the police for any assistance in locating the individual.

Having a complete, well-documented patient chart doesn’t just keep your practice neat and organized, it may help resolve potential patient disputes. Your treatment records are yet another tool to clearly communicate expectations with your patient and build a foundation of trust and transparency.

For more information on record keeping and to access patient forms and associate agreements, visit tdicinsurance.com/reference-guides. ■

TDIC’s Risk Management Advice Line at 800.733.0633 is staffed with trained analysts who can provide guidance on patient records and other questions related to a dental practice.

A P R I L 2 0 1 8 R M M A T T E R S

“Matching the Right Dentist to the Right Practice”

4159 SANTA ROSA GP Dedicated practitioner retiring from practicewith emphasis on Restorative care. Located in a class “A” professionalbuilding in well-travelled area. 2,330 square foot office with 5 ops.,reception area, business office, private office, consult room, stafflounge, lab area, sterilization area, and private bathroom. 4 doctor-days per week and approximately 1,000 active patients and averageGross Receipt of $733K+. Asking $557K.

4225 EUREKA GP & BUILDING Established since 1981 in charmingNorthern California port city. Retiring doctor is offering practice andbuilding. Practice has approximately 1,200 active patients with newpatients accepted on a selective basis. Average Gross Receipts of$765K+ with 61% average overhead. Free standing building at premierHenderson Center location in the Heart of Humboldt county. Beautiful1,400 square foot office with four (4) fully-equipped operatories. Askingprice for practice $468K. Building available to purchase.

4216 SIERRA NEVADA FOOTHILLS 23 year practice located inthe heart of the Sierra Nevada foothills in modern condominiumizedbuilding close to downtown area. 1,024 square foot office with 4 fully-equipped ops., upgraded major equipment and digital radiography.Seller is retiring and looking for a relaxed and personal practitioner forhis loyal patient base. Average Gross Receipts $890K+ with 56%average overhead. Asking price for practice $604K. Seller is offeringreal estate for sale to the buyer of his practice.

4207 MID PENINSULA GP Seller offering 40+ year practice with anemphasis on Restorative and Diagnostic care. Asking $385K.

4178 SONOMA COUNTY PERIO Seller retiring from 21 yearpractice with trained, seasoned staff and great location. Exceptional2,100 sq. ft. ample office with 6 fully equipped ops. Majority ofequipment purchased in 2002. 4 doctor-days & 3 hygiene days perweek. Average gross receipts $1M+. Asking $677K.

4198 NORTH BAY PERIO Established Periodontic practice with loyalreferral sources in 1,564 square foot office with 5 fully-equippedoperatories conveniently located close to Petaluma Valley Hospital.Average Gross Receipts $480K. Seller is offering the condominiumizedoffice for sale to the buyer of the practice. Asking price for practice$284K.

4191 SONOMA COUNTY ENDO Seller retiring from 38 yearendodontic practice located in attractive ground floor office (remodeledin 2011) with updated modern equipment and cabinetry. Close toseveral regular referral sources. Doctor sees an average of 7-8 patientsper day. 5 year average Gross Receipts $700K+. Asking $447K.

4210 UNION CITY GP Retiring GP offering 40+ years of goodwill.Excellent location in Professional Bldg on major thoroughfare. 5 ops in1,100 sq. ft. 350 active patients, all fee-for-service. 2 yr average GR$177K. Seller willing to help for smooth transition. Asking $85K.

4202 SANTA CRUZ COUNTY GP Retiring seller offering 40+ yearsof goodwill with emphasis on restorative care. Asking $300K.

4161 CONTRA COSTA COUNTY ENDO Seller retiring from well-established practice in desirable neighborhood. Located inprofessional center with several loyal referral sources. 1,445 squarefoot office with 3 operatories and current lease with two 5 year optionsto extend. 2016 gross receipts $388K+. Asking $248K.

4196 PACIFIC HEIGHTS SOLO GROUP Enjoy the benefits of awell established successful group while maintaining your individualgeneral practice in a modern fully-equipped office with well trainedpersonnel. Approximately 1,400 active patients with an average of 10new patients per month. Average gross receipts $689K+ with anequivalent of 3 doctor days per week. Asking $423K.

4172 NAPA GP Amazing opportunity to own the practice of yourdreams in one of the world’s premier wine destinations! Situated in aprime commercial and residential mix neighborhood close to shoppingfacilities and many amenities. Seller owned 1,200 square foot well laid-out office with 4 fully-equipped and updated operatories. Over 1,000active patients. Average annual gross receipts over $700K based onthe past 5 years. Asking price for practice $484K. Building available forpurchase.

4219 SANTA CRUZ FACILITY Great dental facility close to severalamenities and minutes to HWY 1, and HWY 17. Plenty of parking andgreat street visibility. Turnkey dental office in 1,200 square foot facilitywith 3 fully-equipped ops. Asking $75K. sale.

4227 REDWOOD CITY GP Profitable, established, general practiceavailable, now, in rapidly growing Redwood City. Over 1,000 activepatients & a 5 year average gross receipts of $890k net. Beautiful re-modeled handicap accessible office with 4 fully-equipped ops. Asking$636K.

4230 SOUTH VALLEY GP Well-established GP offering 30+ years ofgoodwill in very desirable suburb of Silicon Valley. 3 fully equipped opsin 1,000 sq. ft with room for 4th op. Beautifully appointed, pristineoffice in Professional Complex. Owner/doctor works 3 days/week.350+ active patients. 2017 GR $278K w/adj net of $110K. Askingprice $225K.

4229 SARATOGA GP Absolutely beautiful turnkey office offering 30+years of goodwill. All buyer has to do is move in! Fantastic location inwell known Professional Building on well-traveled, major thoroughfare.4 fully equipped ops in 1,500 sq. ft facility. 600 active patients (all fee-for-service). 1.25 days/hygiene week. Last 4 years average GR$285K. Seller willing to help for smooth transition. Asking $290K.

4215 SILCON VALLEY ENDO Practice in prime Silicon Valleylocation with 40+ loyal referral sources. 900 square foot office inmodern professional center with 2 operatories. Averaging 20 newpatients per month. Long term staff. 2017 gross receipts $603k.Asking $399k.

Carroll & Company2055 Woodside Road, Suite 160Redwood City, CA 94061BRE #00777682

Mike Carroll Pamela Carroll-Gardiner

CARROLL& C O M P A N YV

Mary McEvoy Carroll

carroll.company [email protected] (650) 362-7004 (650) 362-7007

PENDING

PENDING

PRACTICE SALES • PARTNERSHIPS • MERGERS • VALUATIONS/APPRAISALS • ASSOCIATESHIPS • CONTINUING EDUCATION

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A P R I L 2 0 1 8 273

A dentist is obligated to make reasonable arrangements for the emergency care of a patient whether or not the patient is a patient of record.

A failure to make reasonable emergency care arrangements for patients of record may result in a charge of patient abandonment. It is unprofessional conduct for a dentist to abandon a patient without written notice that treatment will be discontinued and before the patient has had suffi cient opportunity to secure the services of another dentist.

In addition, dental benefi t plans require contracted providers to arrange for after-hours emergency care of their enrollees. Dentists should check a contracted plan’s provider manual or handbook for the requirements. One major plan requires that emergency care be available 24 hours a day, seven days a week and to have an active after-hours mechanism, such as an answering machine, answering service, cellphone or pager, available for 24/7 contact or instructions. The plan also requires that urgent care be provided within 72 hours when consistent with the patient’s individual needs and required by generally accepted standards for dentistry.

Professional ethics require that a dentist make a reasonable arrangement for emergency care of a patient who is not of record. Treating or consulting with a patient for the fi rst time in an emergency does not make the individual a patient of record.

Examples of reasonable arrangements: ■ Before leaving on an extended

vacation or absence from the practice, arrange for emergency coverage with one or more colleagues. Notify patients in advance and provide contact information for the colleagues.

Managing Emergency Patients CDA Practice Support

Regulatory Compliance

■ For times when the dental practice is closed, leave an outgoing message on the telephone answering system that provides instructions on how a patient can contact the dentist or a colleague who is providing emergency coverage. If using an answering service, instruct the operator to collect information from the patient that includes full name, date seen by the dentist, complaint and a phone number (ensure

Treating or consulting with a patient for the fi rst time in an emergency does not make the individual a patient of record.


274 A P R I L 2 01 8

a HIPAA business associate agreement has been signed with the service). The dentist should have a method for verifying patients of record as well as verifying patients of colleagues for whom the dentist is providing emergency coverage.

After listening to a patient’s complaint, a dentist may choose to:

■ Prescribe pain relief and other medication, as appropriate, with direction to the patient to present for an examination at the earliest possible time.

■ Direct the patient to an emergency room or urgent care facility.

APRIL 2018 REGUL ATORY COMPL IANCE

■ Direct the patient to present at your dental offi ce for an examination as soon as possible.

A dentist who agrees to see a patient at a time when the offi ce is typically closed should take appropriate precautions for personal safety. Dentists are not required to see an emergency patient in the middle of the night. If contacted by a patient in pain in the middle of the night, a dentist can refer the patient to a hospital emergency room or urgent care facility for pain relief and then direct the patient to present at the offi ce at the earliest possible time.

Be sure to keep records of these after-hours consultations.

Do not leave an outgoing message directing emergency patients to contact the local dental society, unless the dental society has agreed to and implemented a plan for handling such calls. A dentist may want to join or start a mutual aid group to formalize arrangements with colleagues for coverage. For more information, review “Practice Interruption and Mutual Aid Group Guidelines” on cda.org/practicesupport.

Reference

CDA Code of EthicsSection 8: Emergency Service

A dentist has the obligation to make reasonable arrangements for the emergency care of his or her patients of record. A dentist has the obligation, when consulted in an emergency by a patient not of record, to make reasonable arrangements for emergency care of that patient.

Advisory Opinion:8.A.1. Continuity of care: In the interest of preserving the patient’s continuity of care, a dentist who treats a patient not of record shall recommend to the patient to continue treatment with the original treating dentist unless the patient expressly reveals a different preference. ■

Regulatory Compliance appears monthly and features resources about laws that impact dental practices. Visit cda.org/practicesupport for more than 600 practice support resources, including practice management, employment practices, dental benefi ts plans and regulatory compliance.

Help is one call away.

The CDA Well-Being Program

If someone you know or love may have an alcohol or chemical dependency problem, contact a support person near you for 24-hour confidential assistance.

Northern California530.310.2395 (cell)

San Francisco/Bay Area209.601.4410 (cell)

Central California916.947.5676 (cell)

Southern California818.437.3204 (cell)

San Diego858.692.4862 (cell)

6140 SAN RAFAEL Dentist retiring after long career. Delta PPO provider. Has averaged $390,000 in annual collections on 3.5-day week. 900+ different patients seen in the last 18-months.6139 SAN FRANCISCO BAY AREA PROSTHODONTIC PRACTICE Very strong pedigree. Well positioned for the future. Excellent platform for younger Prosthodontist. Out-of-network! 2017 billed $1.2 Million and collected $1.19 Million. 4-days of Hygiene. Owner can work back to help assist with transition. 6138 SAN FRANCISCO BAY AREA’S SOUTH BAY Phenomenal opportunity shall secure a rewarding career. Best technology, perfectly designed suite and optimum stage to practice your craft. 2017’s collections topped $900,000. Building included. Perfect for skilled practitioner who seeks 6137 SOUTH SACRAMENTO AREA Growing PPO practice topped $1.5 Million in collections in 2017 rofits exceed $500,000 after paying Associates. 6-days of Hygiene. 6-ops, 3-D Pano and paperless. Over $400,000 invested here recently. Great location.6136 SAN RAMON foundation here. Collections for 2017 totaled $575,000. And this was on a work schedule averaging 2.5-days a week. 3-ops. Seller can work back 1-day a week to assist in transition.6135 SONOMA COUNTY’S ROHNERT PARK 2017 collected $1,050,000 reflecting nice growth over 2016 which collected $940,000. Profits exceeded $500,000 for the second year in a row. 6-days of Hygiene. There shall be no change in fees for theSuccessor. New homes being built nearby.6133 SAN RAMON’S BISHOP RANCH Beautiful 4-op, computerized and digital office. Located in the Bishop Ranch Medical Center. Bring Business Plan. Great addition to existing network. Full Price $150,000 6132 UNION CITY $420,000+ invested here. Very high end for great patient experience. 3-ops equipped (4th available), Panorex, completely networked and digital. $600,000+ in revenues. 6129 FOSTER CITY / SAN MATEO Wish to infuse your practice with quality patients? Out-of-network practice collected $500,000+ in 2017 on part-time schedule. Seller and Hygienist shall relocate into Buyer’s practice to transition patients. Full rice $100,000.6125 OAKLAND’S LAKESHORE VILLAGE Collections average $735,000 per year. High income zip code with well employed Millennials next door. 10+ new patients per month. Digital and paperless.6122 SANTA CLARA - STARBUCKS "LIKE" LOCATION! Best exposure in beautiful strip center. Office just remodeled. 5-Ops. Currently trending $1+ Million in Collections on 4-days. Perfect platform to operate 6-days a week. Can do $1.5+ Million. 6121 NAPA VALLEY FAMILY PRACTICE Highly respected community asset. Collections last 5-years have averaged $1.28 Million per year. Beautiful facility. Condo optional purchase.

RAFAEL Dentist retiring after long career. Delta

NORTHERN CALIFORNIA(415) 899-8580 – (800) 422-2818

Raymond and Edna [email protected]

California DRE License 1422122

SOUTHERN CALIFORNIA(714) 832-0230 – (800) 695-2732Thomas Fitterer and Dean George

[email protected]

California DRE License 324962

ALTA LOMA Shopping Center. Hi identity. Absentee Owner. Grossing $700,000. Hands-on successor can do $1 Million. 5-ops, 3 equipped. BAKERSFIELD Free-standing 3,000 sq.ft. building. 5-Ops. Established 60-years. Can do $1 Million. FP $650,000 includes RE.BAKERSFIELD AREA Small City. Grosses $40,000/month on 2-day week. 1,800 sq.ft. 5-o s with small apt. F P $330,000.BELLFLOWER DDS doing $100,000. 3-ops. FP $65,000.

Hispanic practice grossing $350,000. Absentee Owner.5-ops. Rent $1,450. Hands-on Owner will do $500,000 first year.DIAMOND BAR Korean / Chinese Shopping Center. Very busyuntil 9 PM. Owner works 1-day week. Does $450,000. Hands-onsuccessor will do over $1 Million.GLENDALE / BURBANK Absentee Owner grossing $840,000.Beautiful corner building. Newly renovated. 5-ops with room formore. RE includes small apt. HMO almost pays mortgage. $2 Million location. Gorgeous.INLAND EMPIRE 3,000 sq.ft. building. 7-Adec ops, Cone Beam.Grossing $1.3 Million. F $2.5 Million includes real estate.INLAND EMPIRE DentiCal. Grosses near $300,000. 4-ops. Rent $1,350. F $150,000.INLAND EMPIRE Union Practice can do over $1 Million. 5-ops.IRVINE Female Owner grossing $1.2 Million. 5-ops.LA MIRADA Hi identity shopping center. HMO pays rent. Like new3-ops with 2-more available. Grossing $450,000. Million Dollar location.New next-door tenant with 1,000 family members. Great upside. LAKE FOREST Adec equipped. Like new in appearance. FemaleDDS grossing $385,000. 30 new patients/month. Buyer shall do$500,000 first year. Option to purchase condo.LOS ALAMITOS Gorgeous. 5-ops. Grossing $1.4 Million.Special "All on 4 " Program. Refers out OS, Endo, Pedo, Ortho.Absentee Owner.ORANGE COUNTY BEACH Professional building. 6-opsequipped. Dentrix, digital & computerized. F $150,000.ORANGE COUNTY BEACH CITY Absentee Owner. Grossing$550,000. 4-ops with room for 5th. Hands-on Owner will do $1+ Million first year. Valuable RE possible.ORANGE COUNTY’S FASHION ISLAND Unique situation.Female grossing $400,000.ORANGE COUNTY’S FASHION ISLAND Grossing $650,000.Rare opportunity.PEDO – CHINESE / HISPANIC Grossing $450,000. Longestablished. F $285,000.REDLANDS 6-ops. Long established. Has done $1 Million. Lotsof potential. Low rent. Grossing over $400,000. HMO pays rent.RIALTO 210 Freeway. Professional building on 2.2 acres. HMOpractice once did $1+ Million. Now only $325,000. Can berestored to $1+ Million.SANTA CLARITA 70,000 autos pass daily. 8-ops. AbsenteeOwner. F $250,000.SANTA CLARITA Hi identity shopping center. Owner wants toshare office and remain 2-days in 2-ops. 5-ops available. Possible forlong term employee DDS, with or without ownership. Upscale area.WEST COVINA Grossing $650,000. 2-days hygiene. AbsenteeOwner. Refers out OS, Endo, Pedo. Ortho.

PracticesWanted

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BAY AREA CONTINUED DC-812 REDWOOD CITY Facility: Reasonable rent and great landlord! 740 sf w/ 3 fully equipped ops $100k DG-635 CASTRO VALLEY: Excellent loca on & stellar reputa on! Solo Group Prac ce $$650k DN-771 SOQUEL Facility: The perfect place to sink down roots, raise a family & build an empire! 1100sf w/2 ops + 1 add’l. $$50k DN-774 FREMONT: This opportunity has it all and awaits your talent and skill! 1,150sf w/3 ops + 1 add’l $$150k DG-785 SANTA CRUZ: Known for its amusement park & beach boardwalk, this community has much to offer! 1000sf w/ 4 ops. Now Only: $200k DG-790 SAN JOSE: Two Prac ces being offer at one great price! Priced to sell at $$1.4M. Call to-day for more details! DN-796 SAN JOSE: This well-oiled general prac ce w/ emphasis on trea ng Pediatric pa ents! 3473sf w/10 ops + 2 add’l. $550k DN-806 WATSONVILLE: This quality, family-oriented prac ce thrives $ focuses on delivering quality care. 1,182 SF W/ 4 OPS. $$550K/ Real Estate TBD DN-809 PLEASANTON: Ranked as “one of the best ci es to live in”, one can certainly understand why! 1100sf w/ 3 ops + 1 add’l. $$480k

NORTHERN CALIFORNIA EC-729 GREATER SACRAMENTO AREA: Seller re r-ing! FFS Prac ce and Real Estate Available! EN-664 SACRAMENTO Facility: Great corner loca-

on, excellent visibility & easy access! 2300sf w/ 4 ops. NNow Only: $30k EN-702 SACRAMENTO: Long-established prac ce w/ emphasis on preventa ve den stry! 1600sf w 4 ops + 1add’l. $$450k Real Estate $325k EN-747 CITRUS HEIGHTS Facility: Be the only dental office in this a rac ve, popular Retail Shopping Center! 2200sf w/5 ops + 6 add’l. $$75k EN-749 LINCOLN: Come sink your roots down and enjoy a fantas c lifestyle which can’t be beat! 1877sf w/4 ops + 1 add’l. $$320k EN-755 FOLSOM: A perfect loca on, envied by all! Enjoy an amazing quality lifestyle in this thriving city. 1200sf w/ 4 ops. $$175k EN-768 WEST SACRAMENTO: family-oriented prac-

ce, equipped with updated technology! 1612sf w/4 ops. $$275k

BAY AREA AC-624 SAN FRANCISCO: Wonderful patients, solid income in great stand-alone bldg $$475k AC-649 SAN FRANCISCO Facility: Richmond Dis-trict, 3 ops+1 add’l, Equipment less than 5yrs old $120k AC-782 SAN FRANCISCO: Well maintained, mul -level Professional Medical Complex. 1450 sf w/ 5 ops $250k AN-752 SAN FRANCISCO Facility: 2 months Free Rent! Opportuni es like this one are few and far between! 1007sf w/ 4ops. $$99k BC-710 WALNUT CREEK: Desirable location in stand-alone, single-story bldg. 1313sf w/ 3 ops $150k BC-741 DANVILLE (FACILITY): Move in Ready facility to build the practice of your dreams! ~ 1600sf w/ 3 fully equipped ops $$150k BC-758 PLEASANT HILL (FACILITY): Gorgeous décor & remarkable location! 768 sf w/ 2 ops $$35k BC-789 OAKLAND (Facility): Perfect layout for Pedo or Ortho. 2800 sf w/ 6 fully equipped ops. Plumb-er for 2 add’l $$250k BC-793 BERKELEY: 2-story Prof Bldg. 1382 sf w/ 4 ops & professionally designed for flow $$475k BC-804 EMERYVILLE: Professional Complex (ADA-compliant). 1740 sf w/ 4 ops & room for 2 add’l $395k BG-762 EAST BAY: Stellar, high Quality practice consistently generates ~ $3M annually. 3000 sf w/ 6 ops $$1.99M BG-734 ANTIOCH: The perfect place to work, live and play! Located in desirable professional neigh-borhood. 1,323 sf w/ 4 ops. $$315k CC-798 PETALUMA: Partially equipped dental office for lease. Only $2500/mo for 1400 sf! Call for De-tails! CC-802 SANTA ROSA: Retail shopping center w/ 1200 sf and 4 fully equipped ops $$220k or $260k w/CT Scanner CG-616 NAPA: State-of-the-Art practice. Seller mov-ing out of state! $$425k CN-829 MILL VALLEY: This once-in-a-life me oppor-tunity awaits your drive, talent & skill! 1200sf w/ /3 ops + 1 add’l $$310k DC-786 LIVERMORE Facility: Move In ready & recent-ly updated! 2380 sf w/ 3 fully equipped ops. Plumbed for 3 add’l $$190k DC-805 CASTRO VALLEY: Seasoned Staff and Loyal PT base! 1800 sf w/4 ops in 2-story prof bldg $$420k

NORTHERN CALIFORNIA CONTINUED EN-791 SO. SACRAMENTO CO:

$450k EG-788 ROSEVILLE:

. $300k EN-800 SACRAMENTO:

$150k EN-797 WOODLAND:

Prac ce $650k/ Real Estate TBD EN-803 ROCKLIN:

$425kEN-831 SACRAMENTO“a cut above” $775k FC-650 FORT BRAGG:

$350k for the Prac ce & $400k for the Real EstateFN-754 SO. HUMBOLDT:

Now $150k! GC-472 ORLAND:

$160k GN-717 YUBA CITY: Build-ing available for purchase! $475k GN-746 YUBA CITY: Includes the latest technol-ogy in CBCT Imaging.Prac ce $480k/ Real Estate TBD. GG-769 REDDING AREA:

Prac ce $390k Real Estate $540k GN-799 PARADISE:

Prac ce $375k, Real Estate $325kHG-732 GRASS VALLEY:

$215kHG-815 SIERRA CO: $180k / Real Estate $437kHN-280 NORTHEAST CA: $60k HN-618 SIERRA FOOTHILLS:

$65k HN-740 SHASTA CO:

$475k/ Real Estate $350k HN-773 SUTTER CREEK:

$195k HN-816 CHESTER/ALMANOR AREA:

Prac ce $140k/ Real Estate TBD

CENTRAL VALLEY IC-468 SAN JOAQUIN VALLEY

$425k

CENTRAL VALLEY CONTINUED IG-687 TURLOCK:

$298k IN-764 STOCKTON:

$267.5k IN-776 STOCKTON:

$25kIN-830 LODI:

$360k, Real Estate $300kJC-811 FRESNO COUNTY:

$350kJG-778 FRESNO:

$295k JG-807 FRESNO:

$158kJH-770 MERCED AREA: S

. $410k

SPECIALTY PRACTICES AC-759 SAN FRANCISCO Endo:

$495kBC-784 CENTRAL CONTRA COSTA CO Perio:

$395kBN-801 SAN RAMON Ortho:

$775k EG-826 ROSEVILLE Perio:

$150kEN-821 GREATER SACRAMENTO AREA Perio:

$395k EN-822 SACRAMENTO Perio:

$840k IC-543 CENTRAL VALLEY Ortho:

$125k HG-763 GRASS VALLEY Ortho:

$210k JG-757 VISALIA Perio:

$395k

800.641.4179 [email protected]

Largest Broker in Northern California

Extensive Buyer

Database & Unsurpassed

Exposure allows us to offer you

“ASK THE BROKER” CAN NOW BE FOUND AT WWW.WESTERNPRACTICESALES.COM

BAY AREA CONTINUED DC-812 REDWOOD CITY Facility:

$100k DG-635 CASTRO VALLEY:

$650kDN-771 SOQUEL Facility:

$50k DN-774 FREMONT:

$150k DG-785 SANTA CRUZ:

Now Only: $200k DG-790 SAN JOSE

$1.4M. Call to-day for more details!DN-796 SAN JOSE

emphasis on trea ng Pediatric pa ents! $550k

DN-806 WATSONVILLE:

$550K/ Real Estate TBD DN-809 PLEASANTON:

$480k

NORTHERN CALIFORNIA EC-729 GREATER SACRAMENTO AREA:

EN-664 SACRAMENTO Facility:

Now Only: $30k EN-702 SACRAMENTO:

$450k Real Estate $325k EN-747 CITRUS HEIGHTS Facility:

$75k EN-749 LINCOLN:

$320k EN-755 FOLSOM:

$175k EN-768 WEST SACRAMENTO:

$275k

BAY AREA AC-624 SAN FRANCISCO:

$475k AC-649 SAN FRANCISCO Facility:

$120k AC-782 SAN FRANCISCO:

$250kAN-752 SAN FRANCISCO Facility: 2 months Free Rent!

$99k BC-710 WALNUT CREEK:

$150kBC-741 DANVILLE (FACILITY):

$150kBC-758 PLEASANT HILL (FACILITY):

$35kBC-789 OAKLAND (Facility):

$250kBC-793 BERKELEY:

$475kBC-804 EMERYVILLE:

$395kBG-762 EAST BAY:

$1.99MBG-734 ANTIOCH:

$315k CC-798 PETALUMA:

CC-802 SANTA ROSA:$220k or $260k w/CT

ScannerCG-616 NAPA:

$425k CN-829 MILL VALLEY:

$310kDC-786 LIVERMORE Facility:

$190kDC-805 CASTRO VALLEY:

$420k

Jon B. Noble, MBA Mona Chang, DDS John M. Cahill, MBA

NORTHERN CALIFORNIA CONTINUED EN-791 SO. SACRAMENTO CO: Highly esteemed prac ce to an adoring & apprecia ve pa ent base! 1950sfw/ 5 ops. $$450k EG-788 ROSEVILLE: Do not pass up on this remarkable opportunity! 2700sf w/ 6 ops.. $300k EN-800 SACRAMENTO: Awai ng your talent and skill to take it to the next level! 1200sf w/ 4 ops. $$150k EN-797 WOODLAND: Do not hesitate or this enviable opportunity will fulfill someone else’s dream! 2316sf w/ 6 ops. PPrac ce $650k/ Real Estate TBD EN-803 ROCKLIN: Con nue the philosophy of serving your pa ents as if they are family! 150sf 3 ops + 1 add’l. $$425k EN-831 SACRAMENTO: Loca on & prac ce philosophy make this opportunity “a cut above” others! ~1600sf w/4 ops. $$775k FC-650 FORT BRAGG: Family-oriented prac ce. 5 ops in 2000sf, 6 npts/mo $$350k for the Prac ce & $400k for the Real Estate FN-754 SO. HUMBOLDT: If you love the lure of sea air, a relaxed lifestyle & charm of coastal living, then look no further! 1500sf w/ 3 ops + 1 add’l. Now $$150k! GC-472 ORLAND: Live & practice in charming small town community. 1000sf w/ 2 ops. Seller Retiring $$160k GN-717 YUBA CITY: Seller Re ring. All reasonable offers considered. BBuild-ing available for purchase! 2400sf w/ 5 ops $$475k GN-746 YUBA CITY: State-of-the-Art Equipped! Includes the latest technol-ogy in CBCT Imaging. Real Estate also available! 1600sf w/ 3 ops +1 add’l. Prac ce $480k/ Real Estate TBD. GG-769 REDDING AREA: Offering a full spectrum of general den stry and total care! 2700sf w/ 6ops. PPrac ce $390k, RReal Estate $540k GN-799 PARADISE: This remarkable opportunity is undeniably too good to be true! 1800sf w/ 4 ops. PPrac ce $375k, Real Estate $325k HG-732 GRASS VALLEY: Seller retiring. Well established practice. 1250sf w/ 3 ops. Real Estate also available. $$215k HG-815 SIERRA CO: Perfect location for outdoor enthusiast! 1000 sf w/ 3 ops $180k / Real Estate $437k HN-280 NORTHEAST CA: Only Practice in Town! 900sf w/ 2 ops $$60k HN-618 SIERRA FOOTHILLS: Seller Retiring! Huge opportunity for growth by increasing office hours! 750sf w/ 2 ops $$65k HN-740 SHASTA CO: Beau ful mountain community, well-established prac ce, excep onal long-term staff. 2400+sf w/5 ops + 1 add’l. $$475k/ Real Estate $350k HN-773 SUTTER CREEK: Located in an area known for beau ful scenery, excellent wine and rich history! 1536sf w/4 ops + 1 add’l $$195k HN-816 CHESTER/ALMANOR AREA: The perfect place to work, live and play! Do not hesitate, or this prac ce will be gone! 1250 sf w/ 4ops. Prac ce $140k/ Real Estate TBD

CENTRAL VALLEY IC-468 SAN JOAQUIN VALLEY: High-end restora ve prac ce! 6 ops in 2500+sf office. Call for Details! $$425k

CENTRAL VALLEY CONTINUED IG-687 TURLOCK: Established quality prac ce - remarkable opportunity! 2000sf w/ 5 ops $$298k IN-764 STOCKTON: Well-established, fully computerized, paperless, digital-ized prac ce just wai ng for your talent & skill! 5,000sf w/10 ops $$267.5k IN-776 STOCKTON: Step right in and you won’t miss a beat in this long-established, quality prac ce! 1046sf w/2 ops add’l. $$25k IN-830 LODI: Start living the life! Small town charm, stable pa ent base & low overhead! 1,550 + 800sf w/4ops. $$360k, RReal Estate $300k JC-811 FRESNO COUNTY: Amazing Opportunity! Considerable Goodwill in Community! 3,000 sf w/ 6 ops $$350k JG-778 FRESNO: What a steal. Consistent collec ons over $600k with cash flow over $300k!! 1452 sf w/ 4 ops $$295k JG-807 FRESNO: Reasonable Overhead, Stellar Reputa on, Excellent Loca-

on! 1000 sf w/3 ops $$158k JH-770 MERCED AREA: Stellar family-oriented prac ce with a loyal, stable pa ent base! 1250sf w/ 4 ops.. $410k

SPECIALTY PRACTICES AC-759 SAN FRANCISCO Endo: Union Square. 1190 sf w/3 ops (plumbed for 1 add’l) $$495k BC-784 CENTRAL CONTRA COSTA CO Perio: Seasoned Staff. Office runs like well-oiled machine! 3 ops $$395k BN-801 SAN RAMON Ortho: Don’t wait or you may miss out on this spectac-ular opportunity of a life me! 1865sf w/ 5 chairs/bays. $$775k EG-826 ROSEVILLE Perio: Create your success story with this warm and car-ing, pa ent-centered prac ce! 1000sf w/3 ops + 1add’l $$150k EN-821 GREATER SACRAMENTO AREA Perio: Live, prac ce & play here! It’ll be the BEST decision you’ll ever make! 1700sf w/4 ops + 1 add’l. $395k EN-822 SACRAMENTO Perio: This prac ce is known throughout Sacra-mento for its stellar reputa on! 2200sf w/ 5 ops + 1add’l. $$840k IC-543 CENTRAL VALLEY Ortho: 1650sf w/ 5 chairs in open bay & plumbed for 2 add’l. Strong referrals and PT base $$125k HG-763 GRASS VALLEY Ortho: Avg 30+ pts per day. Newer retail Shopping Center $$210k JG-757 VISALIA Perio: Keep implants in house and imagine the growth possibilities! 9 hygiene days per week! Rare Gem! 2,000 sf w/ 5 ops $395k

Edmond P. Cahill, JD Timothy Giroux, DDS


278 A P R I L 2 01 8

A look into the latest dental and general technology on the market

Tech Trends

Notability ($9.99, Ginger Labs)

Note-taking has an important place in human history. Whether it is on a piece of scratch paper, notebook, mobile device or tablet, the ability to jot down ideas and memorable thoughts is both invaluable and very personalized for each individual. Digital note-taking and its advances, such as the Apple Pencil for iPad Pro, have given consumers a worthwhile alternative to paper. Notability was created to give users the simple capability of writing notes with the fl exibility and freedom that extends far beyond what paper can do.

Notability has myriad features that will satisfy any need. Pencil and highlighter sketch tools can be customized by stroke style, thickness and color. Text annotation can be modifi ed by font, size, color, typography and paragraph style. Eraser, cut and picker tools allow for easy content modifi cation. Voice annotations from the device microphone can also be attached to notes. Paper backgrounds can also be personalized by color and line or graph confi gurations. Imported photos and PDF fi les from other apps can be marked up and annotated. Multiple undo and redo functions give users the ability to correct any mistakes when sketching. Users have options to print, email and share with Dropbox, Google Drive, OneDrive, Box or WebDAV accounts. Notes can be organized into subjects and groups of subjects can be placed under dividers. Furthermore, notes can be backed up to any connected account and kept up to date across MacOS and iOS devices with an iCloud account. Users can purchase multiple themes to further personalize their note-taking space within the app.

Compared with the amount of supplies needed to take detailed notes conventionally, Notability gives users the capability to take powerful notes in a mobile or desktop app without the need for extra supplies. People can now simply put down their thoughts and ideas wherever they go.

— Hubert Chan, DDS

Vero (Free, subscription fee required, Vero Labs Inc.)

In the world of social media, platforms such as Facebook, Instagram and Snapchat are some of the recognizable powerhouses. A new app is gaining popularity, however. It is called Vero and it touts itself as a “true social” experience. The idea is that users can share videos, photos, links, etc. like on other platforms, without the things that are currently hampering the experience on other platforms. Vero claims there are no ads (there is a subscription cost to use it), no diving through user data, the posts show up in chronological order without constant algorithm changes, and it features security settings that allow users to build friend lists. According to reports, downloads of Vero for iOS and Android soared by a whopping 1,465 percent in one week in February. Time will tell if this app makes a true dent in the social media space.

— Blake Ellington, Tech Trends editor

70 Percent of Adults Over 50 Own SmartphonesA new study details the use of technology among adults over the age of 50. The study, conducted by AARP, found that 70 percent of adults in this age group own a smartphone and about the same amount have a presence on social media. In terms of staying connected, text messaging is the preferred method for those between the ages of 50 and 69. Adults who are in their 60s are more likely to use their device to manage medical needs than those who are in their 50s and 70s, according to the study. For the study, 1,520 adults over 50 were surveyed between Nov. 16–27, 2017 . For more information, visit aarp.org.

— Blake Ellington, Tech Trends editor

Would you like to write about technology?Dentists interested in contributing to this section should contact Andrea LaMattina, CDE, at [email protected].

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