The Role of Behaviour in Inequality in Increments of Dental Caries among Finnish Adults

Background: Evidence from cross-sectional studies implies that dental behaviours partially explain inequalities in oral health. Objective: To assess whether dental behaviours completely eliminate inequality in increments of dental caries in a sample of Finnish adults. Methods: The baseline data were collected from the Health 2000 survey, a nationally representative survey of 8,028 individuals aged 30 years or older living in mainland Finland. Four years later, 1,248 subjects were invited for oral re-examination, and 1,049 agreed to participate (84% response rate). At baseline, participants provided information on demographics, education and dental behaviours (dental attendance, tooth brushing with fluoride toothpaste, sugar consumption and daily smoking). Oral examinations at baseline and follow-up were identical. Results: Adults with basic education had significantly greater increments of DMFT (incidence rate ratio 1.41, 95% CI 1.07-1.85) and DT (incidence rate ratio 2.23, 95% CI 1.27-3.90) than those with high education. Adjusting for single behaviours attenuated but did not eliminate education inequality in DMFT and DT increments, tooth brushing having the greatest impact on inequality. Simultaneous adjustment for all behaviours eliminated the significant relationship between education and caries increment. Conclusions: Accounting for important dental behaviours appears to explain all education inequality in dental caries in Finnish adults. The results should be interpreted with caution when applied to less egalitarian populations.