Objective: To investigate factors associated with the prevalence of dental caries in children and to estimate the population impact of water fluoridation on the prevalence of dental caries.
Methods: Australian children were selected through a stratified random sample selection in 2009–2011. Oral epidemiological examinations provided individual-level outcomes: prevalence of dental caries in the primary (among 5–8-year-olds) and permanent dentitions (9–14-year-olds). Socioeconomic status, oral health behaviours and practices and dietary patterns were explanatory factors at the individual-level, school-level while fluoridation status was the explanatory factor at the area-level. Data were weighted to represent the population. Three-level multilevel multivariable models were sequentially specified for the prevalence of dental caries to estimate prevalence ratios (PR) associated with explanatory factors, adjusting for covariates and between- and within-group variances. Population Attributable Fraction (PAF) was estimated as population impact of the statistically significant explanatory factors.
Results: Data from 2,214 5–8 year-olds and 3,186 9–14 year-olds from 207 schools in 16 areas were analysed. The prevalence of dental caries in the primary and the permanent dentitions was 47.1% (43.9-50.4) and 38.8% (36.1-41.6) respectively. The lowest prevalence of dental caries was observed in the fluoridated areas. In bivariate associations, factors at three levels were associated with prevalence of dental caries. In the full models, children in the non-fluoridated areas had significantly higher prevalence of dental caries (PR for the primary: 1.29 (1.11-1.50); PR for the permanent 1.49 (1.01-2.21)) compared with children in fluoridated areas after controlling for other factors. PAF estimates indicated that lack of water fluoridation attributed to 21% and 31% of primary and permanent dental caries respectively in the child population.
Conclusion: Water fluoridation had significant population impact on the prevalence of dental caries in children.