Prevalence of dental caries and dental fluorosis in areas with optimal and above-optimal water fluoride concentrations.

The prevalence of dental caries and dental fluorosis was assessed among 807 schoolchildren in four areas of Illinois where the respective water supplies contained natural fluoride at concentrations of 1, 2, 3, and 4 times the recommended optimal for the geographic area. Mean caries scores in all three above-optimal fluoride areas were significantly lower than in the optimal area. The prevalence of dental fluorosis was characteristically low in the optimal fluoride area. Substantial increases in fluorosis occurred in the above-optimal fluoride areas, with the condition being most pronounced in the 4-times optimal area.