Is caries equally distributed in adults? A population-based cross-sectional study in Norway - the TOHNN-study

Objectives: The aim of the study was to examine the prevalence and distribution of dental caries in an adult population and identify factors associated with being caries free.Material and methods: Data were collected from a randomized population sample in Northern Norway (N=1932; 988 women; mean age 47.0 years, SD 15.3). The study included a structured questionnaire and a clinical examination. The sum of enamel and dentine caries, DS1-5, formed the main outcome measures for caries prevalence.Results: Mean DMFT was 15.1 (95% CI 14.8, 15.4), mean DFT was 12.0 (CI 11.7, 12.2), and mean DT was 1.1 (CI 1.0, 1.2). The mean value for dentine caries (DS3-5) was 0.8 (CI 0.7, 0.9), and mean DS1-5 was 3.8 (CI 3.6, 4.1). Mean DS1-5 was highest in the youngest age group (mean 6.9, 95% CI 6.3, 7.6) and in rural areas (mean 5.0, CI 4.4, 5.6). The most caries-prone 20% in the youngest age group had 52% of the total number of carious lesions compared with 80% in the two oldest age groups. Tooth brushing twice daily (p=.005), drinking sugar containing soft drink (p=.029), and attending dental services every year (p<.001), were associated with being caries free.Conclusion: Dental caries is still a common condition, particularly in the youngest age group. Living in a rural area, low socioeconomic status, less frequent tooth cleaning and sugar containing soft drinks were associated with a higher prevalence of dental caries. The different caries distribution among adults calls for different preventive strategies at both population and individual levels.