TFI measurements in the BC Fluoridation Cessation Study

Objective: To assess TFI maximum score on the anterior quadrant of children in communities with optimally fluoridated (F) water in British Columbia, Canada. Methods: Monthly F water means±SD (1985-92 in Comox/Courtenay and Campbell River; and 1982-93 in Kamloops) were 0.92±0.21, 0.88±0.28, and 0.95±0.27 mgF/L. The communities voted on water F discontinuation in 1992; only Kamloops voted to maintain it. TFI examinations in 5,927 children (grades 2,3,8,9) were done for the 1996-7 follow-up survey (about 50 months after F discontinuation). Multivariate Poisson regression models were used to identify the relationship between TFI and water F status, age, gender, SES, and dietary (use of bottled water or formula) and F exposure histories (supplements, rinses, toothpaste amount, toothbrushing frequency and starting age). Variables were obtained by questionnaire from the parent(s). Results: Low to mild levels of fluorosis were found overall. Females had higher TFI than males (OR=1.24) and residents of the fluoridation-ended communities had higher TFI than the still-fluoridated community (OR=1.10). Children 10 years and older had higher TFI (OR=1.12) than younger children. Consuming bottled water between birth and 6 months (OR=0.78) had a protective effect. Exposure to F technologies was strongly associated with fluorosis experience. Children who began brushing with F toothpaste between the 1st and 2nd birthday had higher TFI (OR=1.12) than those who began between the 2nd and 3rd birthday; but daily brushing frequency was not significant. Children who used F supplements regularly had higher TFI (OR=1.09) than those who did not use supplements. Children with at least one college-educated parent had higher TFI (OR=1.09) than those whose parents had less than a high school education. Conclusions: Slightly higher likelihood of higher TFI maximum scores in esthetically important teeth were associated with higher F exposure, in particular when more F technologies were used at home.