Prevalence and severity of dental fluorosis in primary schoolchildren in Nairobi, Kenya.

The purpose of this study was to assess the prevalence and severity of dental fluorosis in 513 primary school children in Nairobi. The clinical examination was performed in a room with natural daylight using Thylstrup & Fejerskov's index (TFI). Overall, 18% of 6-8-yr-olds had dental fluorosis in the primary dentition and 76% of 13-15-yr-olds in the permanent dentition. There was no significant sex difference (P > 0.05) in either the prevalence or the severity of fluorosis. In children with mixed dentition, the prevalence and severity of fluorosis was higher in the permanent teeth. In the permanent dentition, no clear difference was demonstrable in the severity between the anterior and the posterior teeth. The degree of fluorosis in most of the children in the area served with river water (0.2-0.4 ppm F-) was of a very mild form. However, in the area served with borehole waters, 48% of the children and 40% of the teeth were found to have TFI scores > or = 5. Measures to reduce dental fluorosis are necessary in the latter area.