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

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.

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, DS_1-5, formed the main outcome measures for caries prevalence.

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 (DS_3-5) was 0.8 (CI 0.7, 0.9), and mean DS_1-5 was 3.8 (CI 3.6, 4.1). Mean DS_1-5 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.

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.