Relationship of naturally occurring fluoride in Carroll County, Maryland to aquifers, well depths, and fluoride supplementation prescribing behaviors.

PURPOSE Systemic fluorides are effective in the prevention of dental caries but over ingestion can lead to dental fluorosis. Fluoride supplements may be under-prescribed for children residing in areas where drinking water is derived from wells, because of a lack of knowledge of dental providers or the effort required to test wells for fluoride before prescribing supplements. The purpose of this study was to determine the possible factors associated with fluoride content of well water in a specific county in Maryland, and to determine whether there is a relationship between the amount of naturally occurring fluoride in the well water and the child's fluoride supplementation use. METHODS This study analyzed the fluoride prescribing behavior and the fluoride content of wells from a sample of 197 Carroll County, Md residents. Those individuals that answered a questionnaire about well depth and use of fluoride supplements subsequently were mailed a water testing kit. Water samples were tested for fluoride using a fluoride specific ion electrode. Derivations of well water supplies (aquifers) were obtained from a county geologist. Variance in well depth and aquifer type were correlated to the levels of naturally occurring fluoride. Supplementation practices of children residing in the participating sampled households were compared to results of fluoride analyses of individual wells. RESULTS Results showed that Carroll County well water contains negligible to low levels of fluoride (0.08-0.24 ppm). Pearson r testing showed a positive relationship between well depth and fluoride, r = 0.23 (p < or = .01). ANOVA results showed no significant difference between the 3 aquifers fluoride, p = 0.23. Analysis of the supplementation behavior indicated that the majority (58%) of the children that should have received fluoride supplements were receiving the incorrect dosage or not being supplemented. CONCLUSION Fluoride content of well water may be related to well depths. Fluoride supplementation practices generally were incorrect, even for this community whose wells had less than optimal fluoride content. Fluoride supplementation education may be lacking for dentists, physicians, and their patients. Future research should explore whether there is a relationship between well depth and fluoride content, as found in this study, and the variables associated with the incorrect fluoride prescribing behaviors.