Die Aktualisierung der Leitlinie "Diagnostik und Management von Vorläuferläsionen des oralen Plattenepithelkarzinoms in der Zahn-, Mund- und Kieferheilkunde" wurde im Jahr 2017 begonnen und nach insgesamt 3 formalen Konsensusprozessen im April 2020 abgeschlossen. Sie erfolgte unter Koordination durch die Deutsche Gesellschaft für Zahn-, Mund- und Kieferheilkunde (DGZMK) und federführender Beteiligung der Deutschen Gesellschaft für Mund-, Kiefer- und Gesichtschirurgie. Konkret aktualisiert und präzisiert die Leitlinie den Stand der Kenntnisse und Empfehlungen insbesondere zu folgenden Aspekten: – Die Klassifikationen potenziell maligner oraler Läsionen unter Berücksich-tigung der aktualisierten WHO-Klassifikation von 2017. – Die Sonderstellung der proliferativen verrukösen Leukoplakie – Die Definition der "verdächtigen" Läsion unter Beschreibung klinischer Hinweise auf eine maligne Transformation – Die konkrete Benennung der Untersuchungen, deren Stellenwert nicht durch belastbare Studiendaten gesichert ist – Die topische Kortikoid-Therapie des Lichen, insbesondere intraläsionale Therapien. Darüber hinaus wurden die vorhandenen Empfehlungen aktualisiert und durch Statements und neue Empfehlungen ergänzt. Keywords: Früherkennung, Mundschleimhaut, Screening, Vorläuferläsion, WHO-Klassifikation, Zahn- Mund- und Kieferheilkunde, maligne Transformation

Health services research develops, describes, clarifies, and evaluates health service processes, outcomes and relevant factors that impact on service provision. A consumer/patient focus, contextual relevance and population-relevant pa-rameters in addition to individual-level assessments as well as multidisciplin-arity and multiprofessionalism are characteristic features of health services research. The relevance of health services research in Germany is increasing. Dental health services research should aim to (1) develop innovative, cross-disciplinary care concepts and to implement them, (2) consider the common risk factor approach and dentistry's role in medical services, (3) focus on consumer/patient preferences, and (4) target social and regional health inequalities. To allow methodologically robust and thematically broad evaluations, dental health services research in Germany needs to professionalize and to link with relevant actors in the healthcare system. Keywords: effectiveness, evidenc-based medicine, healthcare policy, methods, public health, research levels

Versorgungsforschung ist ein relativ junger Forschungsbereich, der allerdings in den letzten Jahren deutlich an Aufmerksamkeit gewonnen hat. Keywords: Evidenz-basierte Medizin, Forschungsebene, Gesundheitspolitik, Methoden, Public Health, Wirksamkeit

Objectives: Oral cancer is a considerable health problem with more than 10,000 new diagnosed cases each year in Germany. Comparably little is known about the knowledge of the public on oral cancer and its possible relationship to socioeconomic parameters. It was the aim of this project to investigate the knowledge about risk factors of oral cancer in the State of Schleswig-Holstein in Germany. Methods: A well-known German polling firm formulated a telephone-based survey based on a standardized questionnaire. This survey was validated by a pretest and a representative survey (n=1000) via computer-aided telephone interview (CATI) was carried out by the polling firm within the public of Schleswig-Holstein, Germany. Descriptive statistics of demographic variables of the sample and responses to the questionnaire were reported by means of counts and percentages. Knowledge of the risk factors was further classified according to different socioeconomic categories and their subgroups. All analyses were done with the SPSS for Windows 15.0 software. Results: More than 70% of the sample of the public knew use of tobacco and a prior oral cancer lesion as risk factors. Other risk factors, such as the consumption of alcohol and older age were only identified by around 50% of the sample. The detailed analysis revealed a relationship between a low level of knowledge and socioeconomic factors such as older age, low level of education, occupations such as e.g. blue collar worker and a low income. Conclusions: The survey illustrated that the public of Schleswig-Holstein is not well-informed about the risk factors of oral cancer. In addition, the low level of knowledge was associated with a low level of certain socioeconomic factors. Improved targeted health education and health promotion strategies for the public are recommended to improve early detection and ultimately the prognosis of oral cancer. Keywords: oral cancer, public, risk factors, knowledge, Germany

Purpose: The aim of this study was to investigate the deviations of the implant positions of both impressions and casts using different impression materials and techniques. Furthermore, the existence of a correlation between the deviations of the impression and those of the cast was investigated. Materials and Methods: A reference model was fabricated with 5 Frialit-2 implants parallel to each other. In a standardized experimental setting, 5 stone casts were produced with 5 different techniques using polyether (A) or polyvinyl siloxane (B through E). In 3 groups, a direct technique was used with a medium-viscosity material or a putty-tray material in combination with a light-viscosity syringe material (A to C). In 2 groups, an indirect technique (either 1-step [group D] or 2-step [group E] was used with a putty-tray material in combination with a light-viscosity syringe material. The center-to-center distances were measured for impressions and casts in the horizontal plane using a computer-aided microscope, and the relative and absolute deviations compared to the reference model were calculated. Analysis of variance followed by the post-hoc Scheffé test (parametric data) or the Kruskal-Wallis test followed by pair-wise Mann-Whitney tests (nonparametric data) were used for statistical analyses. Deviations of impressions were compared with their respective casts using paired t tests and the Pearson correlation coefficient. Results: No significant differences for the relative deviations were found for impressions (-5 to -8 µm) or casts (+7 to +16 µm). Group E produced significantly higher absolute deviations for impressions (38 µm) and casts (39 µm) compared to the other groups (11 to 18 µm and 17 to 23 µm, respectively). A significant correlation between deviation of the impression and its respective cast was found for every group (r = 0.40 to 0.80) except group D. Conclusions: The distortions in the horizontal plane of the casts obtained from the impression techniques of groups A to D would probably not affect the clinical fit of implant-retained superstructures. Because of the high variation of deviations (-113 to +124 µm), the 2-step technique cannot be recommended. The method to measure both impression and cast provided a better understanding of how inaccuracies are caused. Keywords: dental implants, impression materials, impression technique, transfer coping

Purpose: The purpose of the study was to investigate how cancer patients with maxillofacial defects evaluate their quality of life after prosthodontic therapy, complemented by a retrospective interview for judging the various therapy steps. The results were compared with a nontumor control group (multiple tooth extractions) and with population-based norm data. Materials and Methods: A total of 34 patients were included in the study, 17 in each group. Patients first filled in a questionnaire and then answered additional questions in a standardized interview. Results: At the time of investigation, tumor patients did not significantly differ from nontumor patients regarding global quality of life. However, tumor patients had significantly less favorable values regarding role functioning, speech, mouth opening, and dry mouth, as well as pain and swallowing. In comparison with the reference data of the German population, tumor patients had considerable deficits (> 20 points) regarding role functioning, dyspnea, and financial difficulties. Other deficits (> 10 points) became apparent in global quality of life, fatigue, insomnia, and appetite. When reflecting the course of disease and recovery, tumor patients rated the diagnosis as the most stressful event and reported that the family was most instrumental in the recovery process. Conclusion: Patients with maxillofacial defects after treatment for malignancy suffer from numerous clearly definable quality of life-related symptoms and problems, even after prosthodontic treatment. These patients need psychologic care at the time of diagnosis to alleviate the burden of the cancer diagnosis and prepare for the demanding treatment. After completion of the prosthodontic treatment, therapy options for pain or speech problems should be offered.

Doppelkronen haben sich über Jahrzehnte zur Verankerung von herausnehmbarem Zahnersatz bewährt. Aufgrund der unterschiedlichen Haltewirkung kann man prinzipiell drei Arten von Doppelkronen unterscheiden: Teleskopkronen (Haltewirkung über Friktion), Konuskronen (Verkeilung) und Doppelkronen mit Spielpassung (zusätzliches Halteelement). Trotz intensiver klinischer Anwendung gibt es bisher nur wenige Studien, in denen der Langzeiterfolg von Doppelkronenversorgungen bewertet wird. In der vorgestellten retrospektiven Studie wird das Therapiekonzept der Marburger Doppelkrone untersucht, in welchem Doppelkronen mit Spielpassung angewendet werden. Diese ermöglichen im Gegensatz zu den anderen Doppelkronenarten auch eine gingivale, resiliente Lagerung der Prothese. Die Ergebnisse zeigen einen guten klinischen Langzeiterfolg mit einem Verlustrisiko für den Pfeilerzahn von 6 % nach 5 Jahren und von 18 % nach 10 Jahren. Diese gute Prognose war insgesamt für alle unterschiedlichen Doppelkronensysteme zu belegen, wenn die Prothese auf ausreichend vielen Pfeilern abgestützt werden konnte. Bei abnehmender Pfeilerzahl je Prothese zeigten starr gelagerte Doppelkronensysteme jedoch ein deutlich erhöhtes Verlustrisiko für den Pfeilerzahn. Bei reduziertem Restzahnbestand scheint hier das Konzept der resilienten Lagerung bei perioprothetischem Design der herausnehmbaren Prothese Vorteile zu bieten, denn mit diesem Konzept wurde in der vorgestellten Studie kein signifikant erhöhtes Verlustrisiko bei abnehmender Pfeileranzahl beobachtet. Keywords: Doppelkrone, Teleskopkrone, Spielpassung, Perioprothetik, Resilienz

The management of head and neck cancer patients is a multidisciplinary approach. Especially patients with persisting maxillofacial defects after surgery experience a restriction of their quality of life during and after therapy. The evaluation of quality of life has become an important aspect in the medical treatment of cancer patients. In dentistry, however, only few information is available how head and neck cancer patients feel during and after therapy.The purpose of this study was to investigate how cancer patients with maxillofacial defects (experimental group) evaluate their quality of life compared to a non-tumour control group with multiple teeth extractions. It is known that patients with a long history of medical treatment adapt to their specific situation (coping phenomenon) and that differences in the global quality of life in comparison with a control group are difficult to detect. So additionally, changes in quality of life during the multidisciplinary therapy were assessed retrospectively.A total of 34 patients were included in the study, 17 in each group. All patients completed their therapy including prosthetic rehabilitation between 1995 and 1999. Global quality of life was measured with a standardized questionnaire (EORTC QLQ C-30). In addition, the patients were interviewed in a standardized format to obtain their retrospective views of quality of life during therapy.At the time of investigation, no significant differences in quality of life were found between both groups but the interview revealed differences in the retrospective evaluation of quality of life. Especially diagnosis, but also surgery and radiotherapy were the most incriminating periods of the therapy for the head an neck cancer patients. The results indicate that these patients need psychological support which should start with the diagnosis and should at least proceed throughout the radiation therapy. Keywords: quality of life, patients with maxillofacial defects, interview

Purpose: It was the aim of this study to investigate the long-term success of a telescopic crown system that can be used for both rigid and resilient support and to evaluate by means of a literature review whether the use of resilient support may be advantageous compared to other double crown systems when the restoration is placed on only a few remaining teeth. Materials and Methods: Patient records were used to evaluate 125 dentures (with 460 abutment teeth) based on the Marburg double crown system. The loss of abutment teeth, endodontic treatment, and fracture of the metallic framework were investigated with regard to the different types of denture support. Results: The probability that a patient would have kept all abutment teeth was 84% after 5 years and 66% after 10 years. No significant differences were found for the two groups esilient support ( three abutment teeth) and igid support ( four abutment teeth). For abutment teeth with a double crown with clearance fit, the risk of loss was 4% after 5 years and 15% after 10 years for rigid support, and 10% and 24%, respectively, for resilient support. The risk of endodontic treatment was 7% after 5 years and 9% after 10 years for rigid support, and 3% and 7%, respectively, for resilient support. None of the denture frameworks showed a fracture during the observation period. Conclusion: Removable partial dentures retained by double crowns with clearance fit and constructed without major or minor connectors provide good clinical longevity. The survival rates of abutment teeth were comparable to those reported in the literature for other double crown systems. There was no significant increase of the risk of abutment loss when the restoration was placed on three or fewer remaining teeth and the concept of resilient support was applied.