Pioneers in Endodontics – Europe and Scandanavia

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91 ENDO (Lond Engl) 2017;11(2):91–103 PIONEERS IN ENDODONTICS Michael Hülsmann, Prof Dr, Department of Preventive Dentistry, Periodontology and Cariology, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany Edgar Schäfer, Prof Dr, Central Interdisciplinary Ambulance School of Dentis- try, Waldeyerstr. 30, D-48149 Münster, Germany Correspondence to: Prof Dr M, Hülsmann, Department of Preventive Dentistry, Periodontology and Cariology, University of Göttingen Robert-Koch-Str. 40, D-37075 Göttingen, Germany Tel: +49-551-3922855 Fax +49-551-3922037 E-mail: michael.huelsmann@ med.uni-goettingen.de Michael Hülsmann, Edgar Schäfer Pioneers in Endodontics – Europe and Scandanavia Introduction Besides the United States, Europe has always been at the centre of endodontic history and progress, with Scandinavia and Germany/Austria/Switzerland being two sub-centres. Many famous pioneers in endodontics originated from these countries and regions. Quite a number of Scandinavian teachers and researchers (Langeland, Spångberg, Bergen- holtz, Tronstad, and others) were educated at Ameri- can universities later in their careers. Therefore, these pioneers are recognised by Drs Gutmann and Man- jarres elsewhere in this issue in their manuscripts on the USA and South/Central America. Certainly, many more pioneers from many dif- ferent countries also significantly contributed to the development of recent and contemporary endodon- tics, and thus the following survey on selected pio- neers does not claim to be representative. It can be observed that the development of endodontology in practice and research in Europe did not show a clear and stringent course, mainly due to World Wars I and II, as for many years current developments were inter- rupted, preventing both the profession and science from progressing. Nevertheless, some of the most famous and important pioneers will be presented. Pierre Fauchard 1678 – 1761 Credited as the founder of modern dentistry, Pierre Fauchard provided in his famous 1728 textbook Le Chirurgien Dentiste (The Surgeon Dentist) (Fig 1) a detailed description of the anatomy of teeth and root canals. Fauchard recommended opening teeth in the case of an endodontic abscess to gain drainage and to leave them open for 2 to 3 months 1,2,3 . He suggested using a mixture of eugenol, ginger, opium, brandy and urine to treat endodontic emergencies and as an intra-canal dressing. For heat cauterisation of the pulp he developed fine and curved pin-type instruments which could be introduced some millimetres into the root canal. For filling of the pulp chamber he took lead foil or used the root canal to fix post-retained crowns, but without appropriate prior treatment of the entire root canal. As early as 1728 he used lead to obturate the tooth, which was limited to the pulp chamber 3 . Philipp Pfaff 1713 – 1766 Pfaff (Fig 2a) studied dentistry in Berlin and follow- ing his military service – including his part in several battles of the Silesian wars – he worked as a barber, who at that time frequently also acted as dentists 2,4 . While serving as a dentist for Friedrich II “The Great”, in 1756, Philipp Pfaff published his textbook “Abhandlung von den Zähnen des menschlichen Fig 1 Left: Pierre Fauchard (taken from Hoffmann- Axthelm 4 ); right: Excerpt from the German translation by Buddeus (1733) of his textbook.

Transcript of Pioneers in Endodontics – Europe and Scandanavia

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ENDO (Lond Engl) 2017;11(2):91–103

PIONEERS IN ENDODONTICS

Michael Hülsmann, Prof Dr, Department of Preventive Dentistry, Periodontology and Cariology, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany

Edgar Schäfer, Prof Dr, Central Interdisciplinary Ambulance School of Dentis-try, Waldeyerstr. 30,D-48149 Münster, Germany

Correspondence to: Prof Dr M, Hülsmann, Department of Preventive Dentistry,Periodontology and Cariology, University of GöttingenRobert-Koch-Str. 40, D-37075 Göttingen, GermanyTel: +49-551-3922855Fax +49-551-3922037E-mail: [email protected]

Michael Hülsmann, Edgar Schäfer

Pioneers in Endodontics – Europe and Scandanavia

Introduction

Besides the United States, Europe has always been at the centre of endodontic history and progress, with Scandinavia and Germany/Austria/Switzerland being two sub-centres. Many famous pioneers in endodontics originated from these countries and regions. Quite a number of Scandinavian teachers and researchers (Langeland, Spångberg, Bergen-holtz, Tronstad, and others) were educated at Ameri-can universities later in their careers. Therefore, these pioneers are recognised by Drs Gutmann and Man-jarres elsewhere in this issue in their manuscripts on the USA and South/Central America.

Certainly, many more pioneers from many dif-ferent countries also significantly contributed to the development of recent and contemporary endodon-tics, and thus the following survey on selected pio-neers does not claim to be representative. It can be observed that the development of endodontology in practice and research in Europe did not show a clear and stringent course, mainly due to World Wars I and II, as for many years current developments were inter-rupted, preventing both the profession and science from progressing. Nevertheless, some of the most famous and important pioneers will be presented.

Pierre Fauchard 1678 – 1761

Credited as the founder of modern dentistry, Pierre Fauchard provided in his famous 1728 textbook Le Chirurgien Dentiste (The Surgeon Dentist) (Fig 1) a detailed description of the anatomy of teeth and root canals. Fauchard recommended opening teeth in the case of an endodontic abscess to gain drainage and to leave them open for 2 to 3 months1,2,3. He suggested

using a mixture of eugenol, ginger, opium, brandy and urine to treat endodontic emergencies and as an intra-canal dressing. For heat cauterisation of the pulp he developed fine and curved pin-type instruments which could be introduced some millimetres into the root canal. For filling of the pulp chamber he took lead foil or used the root canal to fix post-retained crowns, but without appropriate prior treatment of the entire root canal. As early as 1728 he used lead to obturate the tooth, which was limited to the pulp chamber3.

Philipp Pfaff 1713 – 1766

Pfaff (Fig 2a) studied dentistry in Berlin and follow-ing his military service – including his part in several battles of the Silesian wars – he worked as a barber, who at that time frequently also acted as dentists2,4. While serving as a dentist for Friedrich II “The Great”, in 1756, Philipp Pfaff published his textbook “Abhandlung von den Zähnen des menschlichen

Fig 1 Left: Pierre Fauchard (taken from Hoffmann-Axthelm4); right: Excerpt from the German translation by Buddeus (1733) of his textbook.

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Adolph Witzel 1847 – 1906

Adolph Witzel (Fig 3) worked as a general dental prac-titioner in Essen, Germany, before he attended the University of Jena (Germany). In the early 1870s he began his studies on pulpotomy. In a presentation to the German Central-Verein Deutscher Zahnärzte in 1874 on “Antiseptic treatment of diseases of the den-tal pulp”, which was published as a textbook in 1879, he made suggestions for pulp treatment on the basis of histological findings1,2. He supposed that failures of pulp capping were mainly due to bacterial infection, resulting in inflammation of the exposed tissue. To test the vitality of the pulp he used cold water. Before amputation of the pulp Witzel disinfected the cavity for 15 to 30 min with a mixture of creosote and tannin to obtain a clean operating field and to avoid microbial infection of the radicular pulp tissue9. Following the use of arsenic paste for devitalisation of the coronal pulp, the vital pulp stump was capped with iodoform or phenolic paste and an amalgam filling was placed in order to prevent coronal leakage. For disinfection of the root canal he used carbolic acid or phenolic com-pounds, as well as formaldehyde, and for obturation of the root canal he recommended a paste composed of zinc-phosphate and phenol and later iodoform9. Witzel’s suggestions have been regarded as the begin-ning of the era of antisepsis in endodontology.

Advances in the description of endodontic anatomy

György Carabelli, Gustav Preiswerk, Guido Fischer, Hans Moral, Walter Hess, Wilhelm Meyer

In the 19th century some European researchers tried to investigate tooth and root canal anatomy in

Fig 3 Adolph Witzel (taken from Hoffmann-Axthelm4)

Körpers und deren Krankheiten” (Treatise on the teeth of the human body and its diseases), which basically took over many ideas from Pierre Fauchard, whose book was translated into German in 1733 by Buddeus1,5,6,7. Pfaff first described capping of the exposed pulp with pieces of gold or lead in order to keep the pulp tissue vital8. The foils were formed con-vex in order to avoid contact with the exposed pulp tissue. Pfaff also manufactured a set of instruments for heat cauterisation of the pulp (Fig 2b)1,2,3,4,6,7,8. He was also the first to describe intentional replanta-tion of a tooth after extraoral retrograde root canal treatment. It is understood he died after contracting tuberculosis in 17666,7.

Fig 2b Instruments used by Philipp Pfaff. From left to right: three cauteries, three instruments for calculus removal, one dental probe, three instruments for caries removal. Below: cheek retractor to shield the cheek when using a cautery (taken from Hoffman-Axthelm4).

Fig 2a Philipp Pfaff and the cover of his book on the treat-ment of teeth.

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individual approaches1,2,4,10,11,12. The most promi-nent pioneers of that period were Carabelli, Preis-werk, Fischer, Moral, Hess, and Meyer, although many other dentists and scientists also made im-portant contributions13,14.

The Hungarian dentist György Carabelli (1787–1842) (Fig 4) from the University of Vienna was the court dentist of the Austrian Emperor. In 1844 his textbook on tooth and root anatomy (Systema-tisches Handbuch der Zahnheilkunde. Anatomie des Mundes) was published posthumously, followed by research on extracted teeth by Gustav Preiswerk from Basel, Switzerland, in 1902, and Guido Fischer (1877–1959), (Greifswald, Marburg and Hamburg, all Germany) in 1908.

All these pioneers used different methods, try-ing to manufacture replications of the root canal system, whereas Carabelli used root slices. The lat-ter preferred corrosion techniques or different liq-uids to fill root canals, followed by dissolution of the surrounding dental hard tissues with acids. In 1901 Preiswerk used heated “Wood’s metal”, which expanded during setting and thus roughly replicated the main and larger components of the endodontic system. Following this the dental hard tissues were dissolved using potash.

In 1903 Preiswerk had already introduced a his-tologically based terminology for pulpal diseases classifying the state of the pulp as hyperaemia, acute partial or total pulpitis or purulent pulpitis. Instead of metal, Guido Fischer used celluloid, which resulted in improved and more detailed replication of the complex root canal system. It was the merit of Wal-ter Hess from Zurich, Switzerland, to improve these replica techniques. Following dissolution of the pulp tissue he used rubber, which under increasing pres-sure was pressed into the fine ramifications of the root canal systems and then dissolved the roots using hydrochloric acid (Fig 5). Using this technique he studied the internal anatomy of approximately 3,000 teeth. These investigations were accomplished by histological studies on the apical anatomy. In 1914 Hans Moral (1885–1933), a professor in Rostock, Germany, used Chinese ink and made the teeth transparent15. In 63 of 100 maxillary molars he dem-onstrated the presence of a second mesio-buccal root canal. Moral was a Jew and therefore heavily prosecuted by the Nazis. Following his dismissal from

the university in 1933 he committed suicide at the age of 4716,17.

Hess (1885–1980) earned his degree in dentistry in 1908 in Zurich, Switzerland, and was appointed as a professor in 1917. His renowned publication “Zur Anatomie der Wurzelkanäle des menschli-chen Gebisses mit Berücksichtigung der feineren Verzweigungen am Foramen apicale”, (Anatomy of the root canals of the human jaws with special respect to the fine ramifications at the apical for-amen), published in 1917, was a landmark study on

Fig 5 Presentation of root canal anatomy by Hess (1917). The presence of MB2 is clearly visible in some of the specimens.

Fig 4 György Carabelli (Hoffmann Axthelm)

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the complexity of the endodontic anatomy, which is still cited frequently3,15. Despite the shortcomings and limits of his technique, some of his specimens of maxillary molars clearly demonstrated the presence of a second mesio-buccal root canal (Fig 5). Hess also published papers on vital pulp treatment, pulpotomy, iontophoresis and on the theory of focal infection. With the advent of dental anaesthesia, introduced by Einhorn in 1905, and the development of endodon-tic instruments, his focus moved from pulpotomy to improved techniques of pulpectomy. Hess also per-formed research on dental anaesthesia. In 1949 he was given the Honorary Membership Award of the American Association of Endodontists (AAE).

In the 1950s Wilhelm Meyer (1896–1982) from the universities of Göttingen and later Königsberg, in Germany, produced a three-dimensional over-sized replica of root canal systems and impressively demonstrated the anatomical complexity of the ap-ical part of root canals with a multitude of lateral and accessory canals and fine ramifications (Fig 6)18,19. He demineralized the teeth, prepared serial slices, which were then magnified and three-dimension-ally transformed into models made of wax, later of resin. His most important work, “Lehrbuch der normalen Histologie und Entwicklungsgeschichte der Zähne des Menschen” (Textbook of normal histology and development of the human teeth), was published in 1932. Meyer was a member of the national-socialist party NSDAP and because of

that his appointment as head of the University of Freiburg failed.

Friedrich W. Greth 1898 – 1943

In 1932, Friedrich Wilhelm Greth, a professor in Breslau (at that time in Germany) and Leipzig19, proposed one of the first classifications of pulpal diseases based on a combination of clinical symptoms and histological findings (Fig 7)2,3,4,10,11,12,13. He histologically investi-gated the pulp tissue from 500 teeth, using Preiswerk’s classification from 1903. Unfortunately, his investi-gations showed that the correlation between clinical diagnosis and histological findings was not sufficiently high for all clinical diagnoses. Greth was listed as miss-ing in action during World War II20.

Otto Walkhoff 1860 – 1934

Otto Walkhoff first worked as a dentist in a pri-vate office before he became a professor in Munich and Würzburg, Germany21. He wrote several text-books and his most renowned book “Lehrbuch der konservierenden Zahnheilkunde” (Textbook of Operative Dentistry) was published in several edi-tions (Figs 8 and 9). More anecdotally, Walkhoff was claimed to be the first dentist to use radiog-raphy in dentistry. Following a 25-min exposure in the laundry room of his house (“It was a torture!”), he presented a radiograph of his own teeth in 1896,

Fig 6 Replica of the root canal systems of a maxillary canine and bicuspid from Meyer’s collection, demonstrating the complex anatomy of the apical part of the root canal with a multitude of ramifications and accessory canals.

Fig 7 Greth’s investigations demonstrated a poor correla-tion between clinical diagnosis and histopathological find-ings (adapted from Guldener P, Langeland K: Endodontie, Thieme, Stuttgart)).

Histologische Diagnose Zahl der klinischen Diagnosen

Übereinstimmung mit der histologischen

Diagnose in %

Hyperamie 32 21,9

Pulpitis acuta partialis serosa

89 22,5

Pulpitis acuta totalis serosa 63 6,3

Pulpitis acuta 39 15,4

Pulpitis acuta 32 55,0

Pulpitis chronica clausa 79 27,0

Pulpitis chronica aperta ulcerosa

131 94,6

Pulpitis chronica aperta granulomatosa

17 88,2

Total untersuchte Fälle 482

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working on endodontics1,2,3,4,10,11,20. To test pulp vitality he suggested using heated water at different temperatures (thermometry), and as one of the first attempts to introduce antisepsis into endodontics he used camphorated monochlorophenol, rather than creosote, for intracanal medication13, which at least in Germany is still used in some dental offices. He stated that a capping material should be non-irri-tating to the pulp, antiseptic and disinfecting, easily applicable and adhesive to the surrounding dentine8. A combination of iodoform and camphorated chlo-rophenol with menthol has become popular as the root canal filling material “Walkhoff-Paste”9. In later years Walkhoff was also active in research on ionto-phoresis for root canal disinfection.

As well as Witzel, Walkhoff was already heavily engaged in controversial discussions on the regen-erative and reparative capacity of the dental pulp in the 1880s.

Alfred Gysi 1865 – 1957

Gysi studied dentistry at the universities of Geneva, Switzerland, and later at the Pennsylvania College of Dental Surgery in Philadelphia, USA. He was co-founder of the Dental Institute at the Univer-sity of Zurich, in Switzerland, where he worked as a professor from 1906 until 1930. Gysi has mainly become known as a professor of dental prosthet-ics, but he was also the promoter of the so-called Trio-paste, composed mainly of paraformaldehyde, tricresol and creoline, which was first mentioned in 1889. This can be regarded as the start of the mum-mification era; Buckley’s Tricresolformalin and Sar-genti’s N2 later also used formaldehyde-containing substances9. Besides pulp capping, mummification using arsenic pastes and, later, paraformaldehyde was a further attempt to keep at least a part of

Fig 10 Alfred Gysi (from Hoffmann-Axthelm).

Fig 8 Third edition of Walkhoff’s textbook.

Fig 9 The classical restorative dentists as listed in Walkhoff’s textbook: upper row: Fauchard and John Tomes; middle row: J. Taft and W.D. Miller; lower row: Adolf Witzel and G.V. Black.

6 weeks after Röntgen’s discovery3,4. Over the fol-lowing years he worked actively on problems of ra-diation and the sequelae of radiography on human tissues. After moving to Munich in 1901 he began

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for obturation of the root canal and it demonstrated a good antibacterial effect without adverse find-ings9,22, and was clearly superior to other antiseptics used at that time. This represented one of the first attempts to obturate root canals with a biocompat-ible material and was therefore known as “biological root canal treatment”2,3. In 1930 Hermann used cal-cium hydroxide for pulp amputation, which histori-cally represented the first attempt of a vital pulpot-omy. He demonstrated the formation of a dentine bridge when capping exposed or amputated pulps with calcium hydroxide. Some years later calcium hydroxide was also used for pulp capping, referring to the results of Hermann’s research8.

Hermann worked in private practices in Göt-tingen, Hameln, Lemgo, Moers and Frankfurt, all in Germany. In 1912 he took charge of the School Dental Clinic in Frankfurt (Fig 12).

Wilhelm Conrad Röntgen 1845 – 1923

Conrad Röntgen (Fig 13) was at school in Utrecht, in the Netherlands, but was expelled. In 1865 he tried to attend the University of Utrecht, but without success due to the fact that he did not have the ne-cessary credentials. Therefore, he started studying mechanical engineering at the University of Zurich and graduated with a PhD. In 1874 he became a lecturer at the University of Strassburg (then in Ger-many) and later at Hohenheim and Giessen, Ger-many, until finally being appointed as Head of the Physical Chair in Würzburg23.

Although not a dentist, Röntgen made contem-porary endodontics possible by his discovery of “A new kind of rays” – called X-rays – on November 8,1895, in Würzburg (Figs 14 and 15), for which he was honoured with the first Nobel Award for physics in 1901 (Fig 16). In Germany, the term

Fig 13 Conrad Röntgen

Fig 11 Title page of Hermann’s doctoral the-sis on calcium hydroxide from 1922.

Fig 12 Handwritten curriculum vitae by Bernhard Hermann.

the pulp vital and to avoid instrumentation of the root canals1,2,3,8. For cleaning the root canal he recommended hydrogen peroxide in combination with sodium hypochlorite, which for decades repre-sented the standard irrigation regime. It should be noted that at that time success and failure of root canal treatment only could be assessed clinically. Several years later, it was shown that this treatment approach resulted in the frequent development or persistence of apical periodontitis.

Bernhard W. Hermann 1884 – unknown

Bernhard W. Hermann from Würzburg, Germany, introduced calcium hydroxide into endodontics in 1920 (Fig 11), which in 1922 became marketed under the name of Calxyl8. Hermann used the paste

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“Röntgenstrahlen” is more popular than X-rays. Although it took some years until radiography was recognised as an indispensable tool and until suit-able devices were available on the market, this discovery made endodontic anatomy visible for the dentist, allowing more accurate diagnosis and treatment of teeth.

In honour of his work the element 111, a radio-active element with instable isotopes, was named roentgenium in 2004 by the International Union of Pure and Applied Chemistry.

Carl Partsch 1885 – 1932

Carl Partsch (Fig 17) from Breslau (then in Ger-many), was a professor of oral surgery at the Uni-versity of Breslau. He developed techniques for ap-ical surgery, namely cystectomy and cystostomy, operations better known as Partsch I (1892) and Partsch II (1910). He was one of the pioneers of api-coectomy. His technique for preparation of the flap has been termed “Bogenschnitt nach Partsch”24.

Gustav Hedström 1869 – 1948

In 1927, in his doctoral thesis on “Gangrene of the dental pulp and its treatment”, Swedish dentist Gus-tav Hedström mentioned the use of a new type of file, which he had himself developed, that could cut dentine much more aggressively than the traditional K-files. Due to problems building the machines for manufacturing such instruments it took several years until this type of instrument was produced and marketed by the Swedish company Sendoline under the name “Hedstroemfile” or H-file (Fig 18). Hedström was also president of the Swedish Dental Society3,25.

Fig 17 Carl Partsch (from Hoffmann-Axthelm).

Alfred Kantorowicz 1880 – 1962

Alfred Kantorowicz was born in Posen and studied dentistry at the University of Berlin and later medi-cine at the University of Freiburg, Germany. In 1909 he was assistant at the Dental Institute in Munich, where he worked with Otto Walkhoff. In 1911 Kantorowicz received his PhD in dentistry and was made Chairman for Conservative Dentistry at the University of Bonn, Germany, in 1918. In 1933 he was dismissed by the Nazis as a “non-Aryan” and was arrested and taken to a concentration camp for about a year. In 1933 he fled Germany for Turkey and became Head of the Dental School in Istanbul, where he worked until his retirement26.

Kantorowicz further developed the thermometry introduced by Walkhoff and in his textbook “Kon-servierende Zahnheilkunde” (Operative Dentistry) he recommended the use of heated water for the differential diagnosis of reversible and irreversible pulpitis.

Fig 14 Laboratory 1895 in the Institute of Physics at the University of Würzburg.

Fig 15 Title page of Röntgen’s publication on the “Eine neue Art von Strahlen” (A new type of rays).

Fig 16 Certificate of Röntgen’s Nobel Prize from 1901.

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Balint Orban 1899 – 1960

Balint Orban, a Hungarian dentist, started his career at the University of Vienna, Austria (Fig 19). As a Jew he had to stop working at the university and in 1938 after the great Nazi-pogrom, the so-called Crystal Night (“Reichskristallnacht”), he left Vienna and moved to the USA27. At the University of Chi-cago he investigated the reactions of human dental pulp to formaldehyde added to medicaments for the treatment of dentine hypersensitivity. He reported reduced sensitivity and formation of secondary den-tine. In microscopic studies he demonstrated the excellent healing capacity of the pulp tissue. Although his main topic of research was periodontology, he also had a great interest in maintaining non-vital teeth and was involved in the discussion about the focal infection theory11. In 1946 he became editor of the Journal of Endodontia, which only survived three editions. He also published a widely used textbook entitled “Dental Histology and Embryology”.

Fig 19 Balint Orban

Birger Nygaard-Østby 1904 – 1977

In 1939 Birger Nygaard-Østby (Fig 20) from Oslo, Norway, received his doctoral degree for a 220-page thesis on “Tissue changes in the apical periodont following different modes of root canal treatment”. The same year he became a professor at the Uni-versity of Oslo and from there lectured in many countries. In 1957 he reported on the use of EDTA for root canal irrigation, which until today is used for the removal of the intracanal smear layer. He also developed a root canal filling technique using gutta-percha plasticised in chloroform, known as the Kloroperka-N-Ö sealer28.

As an anecdote, highlighting his attitude toward scientific work, he is cited to have obliged to the famous Goethe-words “Du musst, du musst! Und koste es Dein Leben!” (You must, you must! Even if it costs your life!“)29. In 1958 Nygaard-Østby was honoured with the Honorary Membership Award of the AAE and in 1976 he received the Louis I. Gross-mann Award.

In a landmark paper on “Tissue formation in the root canal after total pulpectomy and partial root fill-ing”, Nygaard-Østby was probably one of the first to demonstrate the regenerative potential of the dental pulp. He showed that after some time a hollow space intentionally left apical to the root canal filling ma-terial was filled with cell-rich fibrous tissue28.

Fig 20 Birger Nygaard-Østby

Fig 18 Hedström’s drawings of different types of root canal instruments showing the development towards the Hedström file (lowest instrument).

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Angelo Sargenti 1917 – 1999

For a long time this Swiss dentist was a leader in the field of obturation materials. Together with Richter, in 1954 he developed N2 (the name standing for second nerve), which in different compositions was used as a sealer or a paste-type filling material9,11. It has been – and still is – composed of zinc-oxide, giv-ing it its typical reddish colour and as the pharmaco-logically relevant component paraformaldehyde. The idea behind this formula was to fix the tissue at the amputation site and to keep the apical part of the pulp vital. Due to the content of paraformaldehyde, N2 has always been attracted controversy and its use has been banned by many scientific societies. Sargenti was one of the first to promote single-visit endodon-tics. He also developed the Giromatic endodontic handpiece and introduced reciprocating kinematics for automated root canal preparation which in 1964 was marketed by Micro Méga (Besançon, France)3.

Martin Brännström 1922 – 2001

In 1966 Martin Brännström, from the Karolinska-Institute in Stockholm, presented his so-called “Hydrodynamic theory of transmission of pain”, in which he explained the cause of dentine hypersensi-tivity being due to the movement of fluid within the dentinal tubules in response to different stimuli. An outward flow of fluid can be observed in reaction to cold and inward flow in reaction to hot stimuli. In 1981 he published his research in the textbook “Dentin and Pulp in Restorative Dentistry”.

André Schroeder 1918 – 2004

Swiss-born André Schroeder worked at the Univer-sity of Basel and later at the Department of Op-erative Dentistry in Bern (Switzerland). In 1969 he

became the first full Professor for Dentistry at a Hel-vetian university. He was later appointed Dean of the Medical Faculty (1971–1973) and as Vice Chancellor (1979–1980)30. Schroeder was basically interested and engaged in dental implantology and developed an implant system and initiated the ITI (International Team for Dental Implantology). At the beginning of the 1950s he developed AH 26, the first resin-based root canal sealer, for decades the most frequently used and best-investigated endodontic sealer, which replaced traditional cement-type zinc-oxide eugenol-based sealers. In 1962, Schroeder mixed an antibiotic (tetracycline) and a cortico-steroid (triamcinolone) to create an intracanal medicament, which became famous as Ledermix and is still frequently in use in many dental offices to treat endodontic emergen-cies. In 1977, Schroeder wrote the endodontic text-book “Endodontie: ein Leitfaden für Studium und Praxis”, (Endodontics – a compendium for education and practice), which was published by Quintessence.

Luigi Castagnola

Luigi Castagnola, from Zurich, wrote the endodontic textbook on the treatment of infected root canals: “Die Behandlung infizierter Pulpen und Wurzel-kanäle und ihrer Folgeerscheinungen” (Treatment of infected pulps and its sequelae) in 1951. In this book he described in detail his treatment rationale, which basically followed Walkhoff’s recommendations using parachlorphenolic substances (ChKM). He also advo-cated intentional slight over-instrumentation, which may be interpreted as an early form of a patency-technique. Over a 25-year period he followed more than 1,000 clinical cases with recall periods from two to 18 years treated with that technique and reported a success rate of 68.2% for teeth with apical periodon-titis and 72.7% for teeth without a lesion.

The founders of the European Society of Endodontology

During the 1982 meeting of the American Associ-ation of Endodontists some European endodontists, under the leadership of Gilbert Crussol (France), began to discuss the need for a European Society and a scientific endodontic journal and founded the

Fig 21 Angelo Sargenti

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European Academy of Endodontology. The par-ticipants in this process were Fred Harty (United Kingdom), Gilbert Crussol (France), Peter Guldener (Switzerland), Arnaldo Castelucci (Italy), Giorgio Lavagnoli (Italy), Aviad Tamse (Israel), Basil Tsatsas (Greece), Ralph Mutschelknauss (Germany), Chris Stock (United Kingdom), Cesar Almeida (Portugal), Rafael Milana (Spain) and Henning Rocke (Germany) (Fig 22). In 1983 the society was renamed the Euro-pean Society of Endodontology (ESE), with Giorgio Lavagnoli elected as its first president at the first biennial congress of the society in Venice, Italy31,32.

Frederick John Harty 1927 – 1996

Fred Harty graduated from the University of Mel-bourne, Australia, and moved to the UK in 1955. There he worked in a private dental practice as well as at the Eastman Dental Hospital where he started to deal with endodontics. He authored the endo-dontic textbook “Endodontics in Clinical Practice”, and was elected President of the British Endodontic Society (BES) in 1975. In 1979 he became editor of the Journal of the British Endodontic Society, which one year later was renamed the International Endo-dontic Journal and received international status and still serves as the official scientific journal of the ESE. He retired in 1986 and was killed in a car crash in Melbourne 199633,34.

Jens Ove Andreasen 1935 –

Jens Ove Andreasen from Copenhagen, Denmark, can be regarded as the father of contemporary den-tal traumatology. In 1965 he and his co-workers in Copenhagen started to recall all trauma cases and thus initiated a series of retrospective studies on the

outcome of treatment of different sequelae of den-tal trauma. The studies demonstrated a high rate of treatment failures, driving Andreasen to develop evidence-based treatment guidelines based on a new classification of dental traumatic injuries and a trauma form, which allowed for the collection of more than 60 data per trauma case. In more than 250 publications he systematically investigated all kinds of dental trauma, among these more than 70 prospective studies, giving a profound and detailed insight into the sequelae of trauma and the incidence of complications. All these data could be related to the specific treatment modalities35. To give an example, Andreasen published recall studies on 400 avulsed and replanted teeth and on 400 teeth with horizon-tal root fractures. This resulted in an impressive data-base, comprising data from 40,000 cases, including 4,000 cases with long-term recalls, allowing for the first time sound conclusions on healing and progno-sis of all kinds of dental trauma. His detailed analyses also allowed conclusions on the influence of certain factors on treatment and healing outcome. His text-books on dental traumatology are authoritative and comprehensive compilations, including a systematic approach to treatment of such injuries. Meanwhile, “Traumatic injuries of the teeth”, is in its fourth edi-tion, and is an impressively illustrated and referenced textbook, serving worldwide as the “bible of den-tal traumatology”. The freely available trauma app Dental Trauma Guide, has been launched in 2005 and serves as an important tool for general dental practitioners looking for fast assistance in trauma treatment36. Andreasen was founder and president of the International Association for Dental Trauma-tology (IADT). As recognition of his work he received the Ralph F. Sommer Award of the AAE in 1991 and 10 years later he was honoured with the body’s Hon-orary Membership Award.

Although merely anecdotal: Jens Ove had been invited to lecture for German endodontists in 2010 in Berlin (Fig 23). Unfortunately, the eruption of the Island volcano just a few days before the meeting resulted in the cancellation of all flights from Scan-dinavia. Rather than miss the event, Jens Ove did not hesitate to take his car for a long and exhaust-ing ride to Berlin, and arrived in time to deliver his lecture.

Fig 22 The founders of the European Society of Endodon-tology.

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Ingrid Brynolf 1910 – 2008

Ingrid Brynolf studied dentistry in Stockholm (Fig 24). In 1934 she moved to Umea, Sweden, where she promoted the foundation of the Dental School and was involved in the foundation of the University of Umea. In 1950 she became head of the Department of Oral Diagnostics at the Dental School in Malmö, Sweden. Parallel to her clinical work she studied medicine, taking her final exam in 1957. In her classical studies, “A histological and roentgenological study of the periapical region of human upper incisors”, from 1967 and “Roentgeno-logic criteria for different grades of periapical inflam-mations” from 1978, Brynolf tried to correlate the radiographic appearance of periapical pathosis to histological findings. These criteria later became the basis for the Periapical Index “PAI”, developed by Ørstavik et al in 1986.

Larz Strindberg 1908 – 1972

In 1956 Strindberg published the classic landmark study “The dependence of the results of pulp ther-apy on certain factors. An analytic study based on radiographic and clinical follow-up examinations”37.

Fig 24 Ingrid Brynolf

In this study he defined definitive, unambiguous end points to depict outcomes of endodontic treat-ment, which became the gold standard for outcome studies.

The Scandinavian microbiologists

In the 1980s, a number of Scandinavian endodon-tists, individually or in cooperation with a large num-ber of investigations, tried to give endodontology a sound basis founded on intense research in microbi-ology. The most renowned of these were Åke Möller, Ulf Sjögren, Anders Byström, Bure Engström, Göran Sundqvist, Olav Molven, and later Dag Ørstavik and Gunnar Bergenholtz.

Ake Möller (1916–2009) started his career as a general dentist in Gothenburg, Sweden, where he developed an interest in microbiology, especially related to endodontics38. His doctoral thesis at the University of Malmö was on “Microbiological exam-ination of root canals and periapical tissues of human teeth” and can be regarded as a landmark study on endodontic microbiology. From that time care-ful microbial sampling became the main technique to control bacterial reduction of the root canal. In 1967 he was appointed professor at the University of Gothenburg, and he became the first professor of oral microbiology in 1972. Together with Lars Fa bricius and Gunnar Dahlen, Möller further investigated the bacterial microflora in teeth with pulp necrosis and its influence on apical disease and healing.

Ulf Sjögren (Umea, Sweden), who currently works as a senior lecturer at the Department of Odontology at the University of Umea, is frequently cited for his study on the success rate of root canal treatment, figuring as high as 96% in vital teeth and 86% in teeth with pulp necrosis. Treatment in that study from 1990 was performed using a really sim-ple technique, namely hand instruments, no micro-scope, irrigation with sodium hypochlorite (interest-ingly 0.5%), multiple visits, medication with calcium hydroxide and obturation using the lateral compac-tion technique. The study demonstrated that suc-cessful root canal treatment does not mainly depend on technical equipment, but rather on adherence to some basic biological principles in terms of controlled antisepsis. In consecutive investigations, Anders

Fig 23 Jens Ove Andreasen at his Berlin lecture in 2010 with Michael Hülsmann (right).

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Byström and his co-workers from Umea showed the influence of mechanical instrumentation, irrigation with sodium hypochlorite, use of calcium hydroxide as medication, EDTA and ultrasonic activation on bacterial reduction, resulting in increasing bacterial reduction.

Göran Sundqvist, also from the University of Umea, investigated further issues dealing with the microbiological infection of the root canal system with a special focus on the microbiological aspects of failed root canal treatments. Together with David Figdor (Melbourne, Australia) and his co-workers from Umea he published numerous scientific papers. One of his landmark papers was “Microbiologic analysis of teeth with failed endodontic treatment and the outcome of conservative retreatment”39. In this study Sundqvist was one of the first to report that Enterococcus fae-calis was the most common species recovered in the root canals of teeth with failed treatment. Moreover, Sundqvist strongly believed that infected root canals should not be treated in a “one-visit after treatment because it is not possible to eradicate all infection from the root canal without the support of an inter-appointment antimicrobial dressing”40.

Sundqvist received his DDS from the Royal School of Dentistry Stockholm and was professor and chair-man of the Department of Endodontics at the Uni-versity of Umea from 1981 until his retirement. The close scientific collaboration with David Figdor was reflected by the fact Sundqvist was appointed as visiting professor at the University of Melbourne, Australia41. In recognition of his work he received the Ralph F. Sommer Award of the AAE in 1994.

Miomir Cvek 1927 – 2008

Miomir Cvec from Croatia was active as a partisan during World War II in the former Yugoslavia. After the war he studied dentistry in Zagreb, but later left the country for political reasons, as he refused to become a member of the communist party. He moved to the Swedish Eastman Institute in 1959, where he was active at the Department of Paediatric Dentistry42. His main topic of research was dental traumatology, with a focus on pulpal and periodontal healing after dental trauma. He has become known as the promoter of coronal pulpotomy in immature traumatised teeth, which has become well known

as the “Cvek-pulpotomy.” For treatment of teeth with traumatically exposed pulp and incomplete root development he recommended calcium hydroxide as intracanal medicament to induce formation of a hard tissue apical barrier. In several clinical and histo-logical studies he demonstrated the excellent clinical performance of these techniques. He also performed some research on animals on pulp revascularization. Also well known are his long-term control studies on teeth with horizontal root fractures demonstrating a good chance for healing without invasive treatment and the development of decoronation treatment of teeth with progressive resorption. Having returned to Zagreb he was appointed professor at the Uni-versity of Zagreb in 1994 and nine years later he received the Ralph F. Sommer Award of the AAE in recognition of his work.

Ivar Andreas Mjör 1933 –

Following 20 years (1972–1992) as director of the Scandinavian Institute of Dental Materials (NIOM), Ivar Mjör has been active as a professor of dentistry at the University of Florida since 1993. Among his topics of interest and research studies were the lon-gevity and biocompatibility of dental materials, as well as the structure and physiology of the pulp-den-tine-complex. In a textbook on “Pulp-Dentin Biol-ogy in Restorative Dentistry” (Quintessence, 2011) and several publications – many published together with Karen Heyeraas – Mjör, even in ultrastructural details, described the histology of all components of the dental pulp and the surrounding dentine, demonstrating that both have to be regarded as a functional unit. In 2004 he was honoured for his scientific contributions with the Honorary Member-ship Award of the AAE.

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