6th German Oral Health Study (DMS • 6): rationale, study design, and baseline characteristics.

Objectives: With the First German Oral Health Study (DMS I) in 1989, the Institut der Deutschen Zahnärzte (IDZ) laid the foundation for a population-representative socioepidemiologic monitoring of oral health and care status in Germany. The objective of the sixth wave of the survey was to update the status of oral health.

Research questions: The primary questions address cross-sectional data: 1. What are the current prevalence rates of oral diseases? 2. What associations exist between oral health and other participant characteristics? The third question is based on the comparison of cross-sectional data with previous German oral health studies (trend): 3. How has the oral health and care status in Germany developed from 1989 to 2023? The last two questions require longitudinal data: 4. How do oral diseases change over the course of a lifetime? 5. What individual characteristics influence the progression of (new) oral diseases?

Study design: The DMS • 6 is a combined cross-sectional and cohort study and therefore classified as an observational study.

Study participants: The age groups for the cross-sectional study were selected following the World Health Organization (WHO) recommendations for oral epidemiologic studies. These include 12-year-olds as representatives for younger adolescents, 35- to 44-year-olds for younger adults, and 65- to 74-year-olds for younger seniors. An additional age group of 8- and 9-year-olds (younger children) was included to obtain information on oral health during the mixed dentition phase. In total, 3,377 study participants were included in the analyses for the cross-sectional questions (prevalences). Participant characteristics provide insights into their sociodemographic and behavioral parameters.