Dental fluorosis in children exposed to multiple sources of fluoride: implications for school fluoridation programs.

Naturally occurring fluorides of varying levels made possible a study do determine if continuous, lifetime use of home drinking water fluoridated to optimum levels combined with the use of school fluoridated water beginning at school age causes objectionable levels of dental fluorosis as defined by Dr. H. Trendley Dean in 1936. Examinations were performed on 120 children who had fluoride concentrations in home well water ranging from 0.1 to 6.5 ppm and attended a school with a private water source containing 4.5 ppm natural fluoride (5.6 times the optimum for community fluoridation in the area). Fluorosis scores were calculated for each of four groups formed according to fluoride concentrations in home water supplies. The group with an average concentration of 0.87 ppm was found to have a Community Index of Dental Fluorosis well within Dean's normal limits. The results suggest that children consuming water at home containing the optimal fluoride concentration and drinking water at school containing the recommended fluoride level (4.5 times the optimum) are not at risk to dental fluorosis that impairs appearance. If this finding is corroborated by future clinical studies, the target population for school fluoridation can be expanded and the administration of these programs facilitated.