RESUMO
OBJECTIVE: To determine the prevalence and severity of dental fluorosis, as well as factors associated with its occurrence, in seven cohorts of children before and after the implementation of a fluoridated salt program in 1991. MATERIAL AND METHODS: A cross-sectional study was carried out in 1,373 children aged from 6 to 12 years in Campeche, Mexico. Data were collected by means of a questionnaire administered to mothers and a dental examination of the children. Modified Dean's criteria were used to diagnose dental fluorosis. A multivariate logistic regression model was used to evaluate the relationship between dental fluorosis and independent variables. RESULTS: The prevalence of dental fluorosis was 51.9%. The most common degree of dental fluorosis was very mild, with 84.7%, followed by mild, moderate, and severe with 13.1%, 1.7%, and 0.6%, respectively. The multivariate model adjusted by number of additional sources of fluoride, age at the beginning of use of toothpaste, and level of schooling of the mother, showed that children born in 1990 (OR = 1.74; CI 95% = 1.36-2.22), 1991 (OR = 4.03; CI 95% = 2.58-6.28), and 1992 (OR = 10.41; CI 95% = 5.77-18.78) were more likely to have dental fluorosis than those born in the period 1986-1989. The frequency of toothbrushing (OR = 1.63; CI 95% = 1.37-1.95) was also associated with dental fluorosis. CONCLUSIONS: A close relationship was found between exposure to toothpaste and dental fluorosis. Implementation of the fluoridated salt program greatly increased the risk of fluorosis.