6th German Oral Health Study (DMS • 6): fieldwork, data collection, and quality assurance.

Objectives: The German Oral Health Studies (DMS) are nationally representative surveys on oral health in Germany, conducted approximately every 8 years since 1989. The current sixth edition of the study (DMS • 6) was planned and executed in accordance with international standards. A field institute selected from across Europe was responsible for data collection.

Method and materials: For six age groups, data collection for the DMS • 6 took place across Germany from October 2022 to September 2023. Data for a seventh age group had already been collected earlier, in the spring of 2021. In addition to conducting a cross-sectional study with new participants, for the first time, a longitudinal component was included by reengaging study participants from the previous study, the Fifth German Oral Health Study (DMS V). Participation was organized via postal invitations, followed by reminder letters or personal visits if there was no response. Data collection in the field was conducted at temporarily established study centers.

Data collection: The primary aim of the DMS • 6 was to assess the current oral health status, oral health behavior, and the dental care status in Germany. For this purpose, both new study participants and participants from the preceding DMS V study underwent clinical examinations and social science surveys. The clinical examinations followed a standardized protocol outlined in a manual. The social science survey was conducted in two parts: a paper and pencil interview (PAPI) completed at home and a computer-assisted personal interview (CAPI) administered immediately before the clinical examination in the study center. A non-response survey showed no systematic differences between study participants and non-participants, indicating an unbiased data basis. Quality assurance: The DMS • 6 included a comprehensive examination program supported by a multi-stage quality assurance system. This system involved pre-testing of the social science research instruments, conducting a pilot study to simulate the main study, multiple training sessions, and the calibration and certification of the dental study personnel both before and during fieldwork. This ensured a high level of data validity.