Anticaries effect of various concentrations of fluoride in drinking water: evaluation of empirical evidence.

The benefits to be expected from the adjustment of fluoride levels in drinking water have been studied in great depth, but for the most part only with respect to changes from negligible concentrations to approximately 1.0 ppm. This study makes use of previously gathered data on fluoride concentration in domestic water supplies, the average decayed, missing, and filled teeth (DMFT) scores of the 12- to 14-year-old children, and temperature data in conjunction with linear mathematical models to estimate the effect on DMFT of changes in fluoride concentrations from levels above 0.1 ppm to ideal levels. The results of the analyses indicate that the endemic levels of fluoride in a community water supply play a major role in determining the relative benefit of adjusting that water supply to an ideal level of fluoride. If a rational policy decision is to be made with respect to fluoridation for a given community, the endemic fluoride levels must be considered in conjunction with such factors as population size and the anticipated cost to initiate and maintain the program.