[Dental fluorosis prevalence in eight cohorts of Mexicans born during the implementation of the Fluoridated Domestic Salt National Program].

OBJECTIVE: to determine the effect of birth cohort on dental fluorosis in Mexican schoolchildren during the implementation of the national program to fluoridate domestic salt.
MATERIAL AND METHODS: in a cross-sectional study we examined 1,644 schoolchildren 6-13 years old born between 1985-1992 in Campeche, México; a community where there is negligible naturally available fluoride in water supplies. Dental fluorosis was assessed with the Dean’s index in the permanent dentition. Questionnaires were used to identify diverse socio-demographic and socio-economic variables. In the statistical analysis logistic regression was used.
RESULTS: the prevalence of fluorosis was 15.5%. In the multivariate model,we observed fluorosis was associated with larger family sizes (OR: 0.91; 95% CI: 0.84-0.99) and female sex (OR: 0.74; 95%CI: 0.57-0.98). Furthermore, using the cohort of 1985 as a comparison group, no significant dental fluorosis differences were found with those born between 1986-1987; in contrast, in the cohorts born between 1989-1992 the risk of dental fluorosis increased by almost four times (p < 0.05).
CONCLUSION: the prevalence of fluorosis was low compared to other studies in Mexico. In this community with negligible fluoride in water supplies the likelihood of dental fluorosis increased as the windows of susceptibility in birth cohorts were closer to the chronologic beginning of the national domestic salt fluoridation program in 1991. This trend was more apparent after 1991.