Lifetime exposure to water fluoridation and child caries experience

Changing patterns of fluid consumption create a need to re-establish measures of lifetime exposure to fluoridated water to determine the effectiveness of water fluoridation in preventing child caries experience. Objectives: To determine if dental caries experience of Australian children is associated with exposure to fluoridated drinking water. Methods: In this cross-sectional study, a stratified, clustered sampling design was used to obtain information on 16,526 5–17-year-old children enrolled in the School Dental Services from four Australian states in 2003-2005. Children's caries experience (dmfs and DMFS) was recorded by dentists and dental therapists and parents completed a questionnaire that asked about their child's residential history, sources of water for drinking, consumption of non-fluoridated water, other sources of fluoride, dietary risk factors, and socioeconomic status. Fluoride content of drinking water in Australian localities was used together with children's residential history to calculate lifetime exposure to fluoridated water (LEFW) and its association with caries experience was evaluated with multivariate General Linear Modelling with adjustment for possible confounders. Analyses used weighted data with corrections for complex survey methodology. Results: Bivariate associations demonstrated that children with >50% LEFW, compared to children with 0% LEFW, had between 42% and 53% lower dmfs and between 20% to 57% lower DMFS, varying according to age. The multivariate analysis found that the >50% LEFW group had a 52% reduction in mean dmfs compared to the 0% LEFW group (p<0.001) and a 37% reduction in mean DMFS (p<0.001). Conclusions: Greater exposure to fluoridated drinking water was associated with significantly lower caries experience. These results indicate that water fluoridation in Australia continues to provide a significant benefit in terms of child oral health.