Regional variations in caries experience, predictors, and follow-up among children and adolescents in Western Norway.

OBJECTIVE To identify regional differences in, and determinants of dental caries among children in western Norway. MATERIAL AND METHODS We studied dental caries in 705 children aged 12 years and 18 years living in the southern region (n = 403) and other parts of Hordaland County (n = 302) in Norway. Information on oral hygiene, fluoride intake, and sugar consumption was collected using questionnaires. We also collected information from the Public Dental Service (PDS) on the history of decayed, missing, or filled teeth; professional fluoride application; recall and regular check-up intervals and treatment visits. Residence (southern region versus the rest of Hordaland, the reference) was the independent variable. We analysed regional differences in (i) caries prevalence and severity, (ii) potential contributors to caries, and (iii) procedures and routines in PDS. RESULTS Caries prevalence and severity were higher in the southern region (67% and 24%, respectively). Self-reported brushing habits, fluoride use, and sugar consumption patterns were similar between regions. We observed more frequent application of professional fluoride (incidence rate ratio [IRR] = 3.05, 95% CI: 1.99-4.66], fewer check-ups [IRR = 0.88, 95% CI: 0.81-0.95], and fewer treatment visits [IRR = 0.77, 95% CI: 0.60-0.98] among participants in the southern region, compared to the rest of Hordaland. The recall intervals in the southern region were 10% longer among 12-year-olds and 10% shorter among 18-year-olds, compared to their respective counterparts in Hordaland. CONCLUSIONS The observed regional gradients in caries experience mirrored regional differences in dental routines and procedures. Caries-related risk behaviours did not explain the observed differences in caries experience.