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Hakimeh Siadat, DDS, MSc

Associate Professor

Dental Implant Research Center,

Department of Prosthodontics & Dental Implants

Faculty of Dentistry,

Tehran University of Medical Sciences (TUMS)

www.drsiadat.com

Implant supported Overdentures

Dr SiadatDDS,MSc

Facial esthetics can be enhanced with labial flanges

The prosthesis can be removed at night to manage nocturnal parafunction

Fewer implants may be required

Less bone augmentation may be necessary

The treatment may be less expensive for the patient

Long-term treatment of complications is facilitated

Daily home care is easier Dr SiadatDDS,MSc

patients require a fixed restoration because of desire

lack of crown height space may not permit a removable prosthesis. <9 mm

maxillary arch will continue to lose bone

posterior bone loss to continue.

Paresthesia are to be expected. Dr SiadatDDS,MSc

Psychological (feels more like natural teeth)

Less food entrapment

Less maintenance (no attachments to change or adjust)

Longevity (lasts the life of the implants)

Similar overhead cost as completely implant-supported overdentures

Dr SiadatDDS,MSc

Two parts:

1. Patrix: one part of attachment system is usually connected to the implant.

2. Matrix: Fit closely within the matrix, and in cloud into the denture.

•Magnet Attachment

•Ball Attachment

•Locator Attachment

•Bar Attachment

• Bar Attachment with ball or locator Dr Siadat

DDS,MSc

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The majority of mandibular overdentures performed by dentists were with two implants, regardless of factors such as the remaining bone, the opposing arch, and patient complaints. Although this treatment is an improvement compared to a denture, the posterior bone loss continues and the anterior implants may experience greater problems than when additional implants are used.

Dr SiadatDDS,MSc

The mandibular overdenture requires at least 12 mm between the soft tissue and the occlusal plane to provide sufficient space (15 mm from bone level to occlusal plane) for the bar, attachments, and teeth.

Dr SiadatDDS,MSc

•space equal to or greater than 15 mm. Class I

•12 to14 mmClass II

•9 to 11 mm Class III

•less than 9 mm Class IV(J Prosthet Dent 2011;105:332-337)

Dr Siadat

DDS,MSc

The anterior mandible is divided into five equal columns of bone between the mental foramens: A, B, C, D, and E.

Dr SiadatDDS,MSc

OD-1 Implants in the B & D positions independent of each other

• Ideal denture

• Ideal anterior & posterior ridge form

•Cost is a major factor

•Retention only PM-6Dr SiadatDDS,MSc

A) to limit the forward rocking of the restoration during function.

B) allow a greater rocking of the restoration and place greater leverage forces against the implants.

Dr SiadatDDS,MSc

OD-2 Implants in the B & D positions rigidly joined by a bar

• Ideal denture

• Ideal posterior ridge form

• Cost is a major factor

• Retention & minor stability PM-3 to PM-6 Dr Siadat

DDS,MSc

The bar should not be cantilevered off the distal side of the implants.

0 ring

Hader clip

Dr Siadat

DDS,MSc12 mm

OD-3A Implants in the A, C & E positions rigidly joined by a bar if posterior ridge form is good

• Ideal denture

• Ideal posterior ridge form

• Cost is a major factor

• Retention & moderate stability PM-2 to PM-6

Dr SiadatDDS,MSc

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The bar acted as a cantilever

Dr SiadatDDS,MSc

The attachments should be positioned to allow movement of the distal section of the prosthesis (A). Two nonaligned Hader clips will not allow movement (B).

Dr SiadatDDS,MSc

OD-3B Implants in the B, C & D positions rigidly joined by a bar if posterior ridge form is poor

•Division c-h anterior bone volume

•Poor posterior ridge form

•Retention & minor stability PM-3 to PM-6

Height (c-h bone)

<12 mm

Dr Siadat

DDS,MSc

Dr SiadatDDS,MSc

OD-4 Implants in the A, B, D & E positions rigidly joined by a bar cantilevered distally about 10 mm

•Greater retention, major stability, & support

• PM-2 to PM-6

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

OD-5 Implants in the A, B, C, D & E positions , rigidly joined by a bar cantilevered distally about 15 mm

•Patient has higher desires

•PM-0

Dr SiadatDDS,MSc

Arch shape affects the anteroposterior (A-P) distance.

ovoid arch form, 6 to 8 mm

square arch form, 2 to 5mm

tapered arch form, larger than 8 mm

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

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The prosthetic design will depend on the distribution of the implants over the arch, their location & their number

Type of prosthesis in the opposing jaw will influence the implant- prosthodontic design

The intermaxillary relationship

The occlusal scheme is influenced by all these factors

Esthetic consideration have to be involved

Dr SiadatDDS,MSc

Transitional prosthesis

Financially compromised patient

Implants placed too far from posterior to connect

with a bar

Implants within 10o of parallel positions

Indication

Dr SiadatDDS,MSc

Insufficient space available & Bar

attachment can’t used

In cases of severely tapering anterior arches

Patient with impaired vision or physical limitations

that would make more intricate oral hygiene

difficult

Indication

Dr SiadatDDS,MSc

To ensure that the retentive

anchors function perfectly

over a long period of time,

the implants must be placed

as parallel as posible to one

another & vertical to the

occlusal plane to create a

tangential axis of rotation

Dr SiadatDDS,MSc

The implants must always be placed at an

angle of 90 to the occlusal plane to ensure

that they are loaded axially.

Dr SiadatDDS,MSc

If the implants are not vertical to the occlusal plane

Implants less than 10 mm in length

Patient with a history of chronic pain unable to

tolerate a tissue supported denture

Lack of parallelism between implants (>10o)

Contraindications

Dr SiadatDDS,MSc

Minimum of two implants required (primarily

lower jaw)

Can retrofit existing prosthesis

Hygienic ease

Can often accommodate unfavorable jaw

relationships

Significant improvement of retention compared to a

denture

Advantages

Dr Siadat

DDS,MSc

Soft- tissue supported

Poor implant support & stability

Attachments may need servicing or replacement

Some movement is still present with resiliency

Disadvantages

Dr Siadat

DDS,MSc

Dr Siadat

DDS,MSc

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Dr SiadatDDS,MSc

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DDS,MSc

Dr Siadat

DDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

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To ensure stability, the production

& integration of a metal

reinforcement in the full lower

denture is recommended

Supporting Frame

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Titanium housing

Ball attachment

Lamella retention insert

Prosthetic phase

Dr Siadat

DDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

The gold matrix

consist of a gold alloy

The four lamellae

function like a spring

PVC ring

Dr Siadat

DDS,MSc

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Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Retainer Housing Ring- spring Thread

Dr SiadatDDS,MSc

If retention is lost, the

spring can be replaced

Dr SiadatDDS,MSc

Custom-made abutment. Note parallel

position with other abutmen

(J Prosthet Dent 2004;92:216-9.)Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

Mucosal inflammation and

swelling around a 43 implant.

Pericoronitis type of

peri-implantitis

Dr Siadat

DDS,MSc

Dr Siadat

DDS,MSc

Maxilla: 4 or more implants

Mandible: 2 or more implants

Dr Siadat

DDS,MSc

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2 implants =

geriatric treatment

3-4 intraforaminal

implants : length of bar

segments must be

adequate (12 mm)

Dr SiadatDDS,MSc

4 implants are

necessary

Dr SiadatDDS,MSc

Fully edentulous arch

Extensive bone or soft- tissue loss

Compromised patient manual dexterity (skill)

Necessity for flange extension

Phonetic concerns in upper jaw

Indication:

Dr SiadatDDS,MSc

Inadequate interarch distance (less than 12 mm)

Patient’s desire for non- removable prosthesis

Insufficient implant support for implant supported restoration

Patient inability to tolerate some movement from tissue supported design

Contraindications:

Dr SiadatDDS,MSc

Patient removable prosthesis for oral hygiene access

Soft- tissue flange support may be an aid for

esthetics

Does not require longer implants

Does not require significant implant parallelism

Screw- hole emergence not critical for esthetics

Advantage:

Dr SiadatDDS,MSc

Attachment servicing

Resiliency and soft- tissue support if previous symptoms of chronic pain

Bar is lingual and difficulty with speech

Anterior tipping of overdenture

Increased screw loosening

Increased moment forces on anterior aspect of prosthesis

Disadvantages:

Dr SiadatDDS,MSc

The anterior bar is positioned perpendicular to the median

line of the two halves of the alveolar ridge.

Bar- retained Overdenture

Dr Siadat

DDS,MSc

The bar must be

horizontal – even if the

ridge varies in height.

The bar must never be

allowed to slope as this

would impede the

correct functioning of

the bar attachment &

create undesirable

horizontal forces.

Dr Siadat

DDS,MSc

Dr Siadat

DDS,MSc

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Dr SiadatDDS,MSc

Egg shaped cross – section

U shaped cross – section

Round bar

Dr SiadatDDS,MSc

It is allowing three degrees of freedom (translateral &

rotary movements )

Mini = 2.3 mm

Standard = 3 mm

Dr SiadatDDS,MSc

The bar attachment is a rigid retentive unit with no

rotational freedom

Mini = 2.3 mm

Standard = 3 mm

Dr SiadatDDS,MSc

It is permitting only one degree of freedom

(translateral movements )

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc

Dr Siadat

DDS,MSc

Prosthetic phase

Siadat et al, Journal of Dentistry, 2007; Vol: 4, No.2. Dr Siadat

DDS,MSc

Check osseointegration

Dr Siadat

DDS,MSc

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Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

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Prosthetic phase

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Prosthetic phase

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Prosthetic phase

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Prosthetic phase

Prosthetic phase

Dr Siadat

DDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

Ultrasonic bath

Acid bath

Sandblasting

Prosthetic phase

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DDS,MSc

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To protect the

margins, an

analog can be

screwed on

during

polishing

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

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Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

Prosthetic phase

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DDS,MSc

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Activator

Deactivator

(standard)

Deactivator

(mini)

3 mm

2.3 mm

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr SiadatDDS,MSc

Prosthetic phase

Dr Siadat

DDS,MSc

Can be divert until 40 degree

Dr Siadat

DDS,MSc

white

1°-10° *

5 lbs**

pink

1°-10° *

3 lbs**

blue

1°-10° *

1.5 lbs**

green

11°-20° *

3-4 lbs**

red

11°-20° *

0.5 lbs**

** lbs = retention force* For the correction of angle divergence

2.27 kg 1.36 kg 0.68 kg 1.36-1.84 kg 0.23 kg

Dr Siadat

DDS,MSc

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Dr SiadatDDS,MSc

Abutment tightening - manually

Dr SiadatDDS,MSc

Abutment being tightened to

35Ncm

Dr SiadatDDS,MSc

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Dr Siadat

DDS,MSc

Dr Siadat

DDS,MSc

Dr Siadat

DDS,MSc

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Dr SiadatDDS,MSc

Application of a mandibular midline implant to support an overdenture.

Dr SiadatDDS,MSc

Dr SiadatDDS,MSc