Distribution pattern of enamel fluorosis severity: What is it telling us about local fluoride exposure?

Introduction and objective: dental fluorosis severity reflects fluoride exposure during dental enamel development. Recently, prenatal and postnatal exposure to fluoride has been associated with negative neurodevelopmental outcomes. The aim of this study was to describe and compare the severity and distribution pattern of dental fluorosis in the primary and permanent dentition, as a basis to discuss the timing and extent of fluoride exposure of children living in endemic areas of fluorosis in the department of Huila. Materials and methods: 840 children (preschoolers and schoolchildren) from four municipalities of the Huila Department were examined by trained dentists for dental fluorosis using the Thylstrup & Fejerskov Index. To estimate the prevalence of severities of fluorosis, each child was classified according to the most severe score. The distribution of the prevalence of enamel fluorosis severity by age-group  and type of dentition were reported as prevalence rates (%). Results: Prevalence of dental fluorosis in preschoolers was of 97.2% and in schoolers of 99.9%. For both preschoolers and schoolers moderate fluorosis was the most prevalent (75.6% and 63.5%, respectively). For both primary and permanent teeth, mild fluorosis was more prevalent in anterior teeth than in posterior teeth. Moderate and severe fluorosis were more prevalent in posterior teeth than in anterior teeth. Conclusions: the distribution pattern of the severity of dental fluorosis suggests both prenatal and postnatal exposure to fluoride above recommended levels. This study raises the importance of the validation of dental fluorosis as a potential historical biomarker of fluoride exposure at moments that are critical for neurodevelopment.