Caries prevalences among geochemical regions of Missouri

Our objectives were to determine how the prevalences of caries in elementary school children vary between geochemically defined regions of the state of Missouri and to compare this variation with that found for prehistoric Missouri inhabitants (Hildebolt et al.: Am. J. Phys. Anthropol. 75:1-14, 1988). Caries data on 6,584 school children were used in the study of second and sixth graders drinking optimally and suboptimally fluoridated water. Geochemical regions were based on maps recently published by the United States Geological Survey. Differences in mean caries scores and proportions of children with caries were tested by analysis of covariance, analysis of variance, Student t, and chi-squared tests. We found that caries prevalences do vary between the geochemical regions of the state. In the total sample, however, there were no significant differences between those children drinking optimally fluoridated water and those drinking suboptimally fluoridated water. We conclude that there is variation in caries rates among geochemically defined regions of the state and that geochemical factors associated with young parent materials may be antagonizing the action of fluoride.