Fluoridation Exposure and Dental Caries in Australian Defence Force Personnel

While there is good evidence of caries-preventive benefits of fluoride in drinking water among children and adolescents, there is little information about effectiveness of water fluoridation among adults. Objectives: To determine whether exposure to fluoride in drinking water is associated with caries experience in Australian Defence Force (ADF) personnel. Methods: Cross sectional study of 876 deployable ADF personnel aged 17-56 years. At each person's mandatory annual dental examination, military dentists recorded the number of decayed, missing and filled teeth (DMFT) using visual, tactile and radiographic criteria. Participants also completed a questionnaire in which they listed where they had lived in each year from 1964 to 2003. People were classified into four categories according to the percentage of their lifetime living in places with fluoridated water: <10%, 10-<50%, 50-<90% and >=90%. Mean DMFT was compared among those categories of fluoridation exposure and the association was evaluated statistically using analysis of variance to adjust for age, sex, years of service and rank. Results: Without adjustment for confounders, mean DMFT (±95% confidence interval) was 6.3±0.8 for <10% fluoridation exposure, 7.8±0.8 for 10-<50% exposure, 7.5±0.7 for 50-<90% exposure and 4.6±0.6 for >=90% exposure (P<0.01). However, age was inversely associated with mean DMFT and in the <10% exposure group, 91% of people were aged <35 years. Service rank was also significantly associated both with fluoridation exposure and DMFT. After adjustment for all covariates, mean DMFT was 24% lower in both categories that had >=50% exposure compared with the <10% exposure group. Conclusions: Degree of lifetime exposure to fluoridated drinking water was inversely associated with DMFT in a dose-response manner among this adult military population. Supported by: Centre for Military and Veterans' Health ; Australian Dental Research Foundation.