Lesion scoring in field vole teeth: Application to the biological monitoring of environmental fluoride contamination

The relationship between fluoride-induced lesions, measured using an increm ental scoring system, and fluoride concentration was investigated in the te eth of the field vole (Microtus agrestis). Both the magnitude of lesion sco re and the severity of observed lesions in both incisor and molar teeth was correlated with the respective tissue fluoride concentration. This: relati onship was observed not only in animals trapped from sites contaminated by industrial fluorides, but also those bred and maintained under laboratory c onditions and consuming fluoride in either diet or drinking water. Although some variation occurred between field and laboratory animals as to the mea n fluoride concentrations in the incisor or molar for each specific lesion score, this may result in part from differences in the nature of the assimi lable fluoride in laboratory diets compared to those consumed by wild anima ls. The practical application of the relationship between dental lesion sco re and tissue fluoride concentration to monitoring environmental fluoride c ontamination is discussed, Because the incisor and molar teeth of the field voles are open-rooted and grow throughout life, they are sensitive to even minor temporal changes in fluoride concentration in tissue fluids and bloo d and, by inference, in the diet and the environment. Therefore, assessment of visual lesions in the dentition of wild-caught field voles may provide the basis of a scheme to monitor the magnitude and effects of environmental fluoride contamination on populations of wild and domestic mammals. The de velopment of nondestructive methods to allow the repeated examination of th e teeth of captured field voles, and hence the dynamic monitoring of enviro nmental fluoride contamination, is also considered.