Population Effects During Early Adulthood of Lifetime Exposure to Fluorides

Epidemiological studies demonstrate clear dental health benefits during childhood of lifetime exposure to fluorides in drinking water and toothpaste. However, it is unclear whether an ongoing caries preventive effect persists into adulthood, or whether caries onset is merely delayed. Objectives: to compare population caries increment over 17 years among four cohorts of the Australian population differentially exposed to fluorides. Methods: Oral examination data from a representative sample of 4,905 people aged 22-89 years were obtained from Australia's second national oral health survey conducted during 2004-06. The number of decayed, missing and filled teeth per person (DMFT) was computed for 17-year birth cohorts. Population caries increment was computed by subtracting mean DMFT recorded for the same birth cohorts during examinations of 9,479 people aged 5-72 years in the first national examination survey, conducted 17 years earlier in 1987-88. To test the hypothesis that lifetime exposure to fluorides conferred ongoing benefits through adulthood, we compared population increment for the 1967-83 birth cohort, which during childhood predominantly used toothpaste containing fluoride and approximately half of whom were exposed to fluoridated water, with population increment in earlier birth cohorts, which were effectively unexposed to such fluorides during childhood. Results: Population increment in the 1967-83 birth cohort was 3.9 DMFT (95% confidence interval [CI] = 3.4-4.4) which was not meaningfully different from the increments observed in the 1950-66 birth cohort (3.4 DMFT, 95%CI=2.9-4.0) and the 1933-49 birth cohort (3.5 DMFT, 95%CI=3.0-4.0) (Figure). Conclusion: The 1967-83 birth cohort of Australians exposed to historically high levels of fluoride was not "immunized" against caries in adulthood, and instead experienced delayed onset of caries. Supported by: NHMRC (#299060); AIHW; Federal and State/Territory Governments; Colgate Oral Care; Australian Dental Association.