Dental fluorosis and fluoride mapping in Langtang town, Nigeria.

This study is aimed at measuring the fluoride concentrations of different water supplies in a Nigerian community known to have endemic fluorosis. This is with the view of mapping out a pattern and to investigate the relationship of this pattern with the distribution of dental fluorosis among residents of the community. A representative sample of 475 persons selected on the basis of criteria described in an earlier publication, constituted the study subjects. Clinical examination were carried out after obtaining sociodemographic information from the subjects. Analyses of fluoride concentrations in 136 water samples revealed, in general the highest levels in stream water range: 2.39-3.96 ppm, followed by wells (range: 1.26-2.82 ppm) and the least in pipe-borne water (range: 0.5-0.97 ppm). In plotting specific fluoride readings from the different identified sources on the geographical map of the study area, a distinctive pattern emerged. High fluoride readings were generally in the highland areas from which rivers and streams took origin. Approximately 50% of the town was supplied with water containing fluoride above the optimum. As reported in the earlier publication, the prevalence of dental fluorosis was found to be 26.1%. The age specific prevalence rate indicated the highest occurrence rate among those aged 10-19 years. Six of the participating children had involvement of deciduous teeth. Even though no correlation was established between dental fluorosis and sex on one hand and fluorosis and ethnicity on the other, there was a markedly significant association between fluorosis and source of drinking water (P < 0.05). Those who drank from streams appeared more likely to have fluorosis. It was concluded that though other sources of fluoride ingestion have been documented, it appeared that water may play a very significant role in the aetiology of fluorosis in this community.