Effect of School Water Fluoridation on Dental Caries, St. Thomas, V.I

Since the fall of 1954, fluoride has been added to the water supply of the Lincoln School in the town of Charlotte Amalie, St. Thomas, V.I., a community with fluoride-deficient sources of drinking water. To compensate for exposure of the children to fluoridated water at school but not at home and for their age when first exposed, a fluoride level of 2.3 ppm was postulated as a suitable level for investigation. Analysis of 96 water samples taken during 8 school years indicated an average school-year fluoride level of 2.34 ppm. However, the water was sampled most frequently after the fluorides were added or just after the equipment was serviced or repaired, and this figure therefore may represent an overestimation of the actual levels of fluoride maintained during the study period. A dental survey conducted in the fall of 1962 showed that the caries level of children who had attended only the test school was substantially lower for all but one grade than the level of children who attend other comparable schools in the same community where the water was fluoride deficient. The difference of 21.9 percent for all children in the test school in their mean proportion of teeth affected by dental caries was significant at a probability level of less than 0.001.