RESUMEN
The incidence and severity of dental fluorosis in 269 school boys aged 6-12 years in four different districts of Gizan region were studied in relation to the water fluoride content in these areas. All children were born and were permanent residents in the respective areas in which they were examined. The water samples analysed for fluoride concentration were obtained from water sources which were the only ones available for the last 10 years. Dental fluorosis affected 38% of the children in areas where fluoride levels in drinking water were less than 1.0 ppm. Very mild-to moderate fluorosis dominated in the primary teeth while moderate to severe fluorosis dominated in the permanent teeth. The most severe fluorosis was seen in the last erupting teeth. Teeth with moderate and severe florosis were more frequently affected by dental caries than teeth with very mild or no fluorosis. It seems that climatic factors and not weather affect the water consumption of the children and hence their total fluoride intake exceeds the permissible limit