Abstract
Mitchell, S. Dakota, accidentally fluorinated its community water to a mean level of 1.15 ppm. (F) for a period of 18 months subsequent to Aug., 1935. Mouth-mirror dental examinations were given 2140 children of this community during the winter of 1947-48. Of this number 339 children aged 11-15 were subsequently found to have had no other fluoride exposure. No inhibition of dental caries could be demonstrated in this group, though about 8% exhibited mild or very mild dental fluorosis. The findings were interpreted as weakening the hypothesis that the caries inhibitory effect of natural fluoride waters depends essentially upon the deposition of fluorides in tooth enamel during the period of calcification.