A laboratory assessment of enamel hypoplasia of teeth with varying severities of dental fluorosis

The effect of lifelong exposure to drinking-water containing fluoride on to oth enamel microhardness was investigated. Dental fluorosis of teeth from a dult subjects, who Lived continuously since birth in areas characterized by the hot climate of India, supplied by drinking-water containing between 0. 5 and 8.7 parts/10 F, was estimated by the Dean score. Tooth enamel section s were examined from the enamel surface towards the dentino-enamel junction (DEJ) for microhardness. Separated enamel crowns were pulverized and analy sed for fluoride. Regarding the distribution of the fluoride concentrations in the drinking-water, we selected a partition below and above 0.8 parts/1 0 F as a criterion for comparison between the results. Tooth enamel of huma ns from Israel living in a drinking-water area containing about 0.5 parts/1 0 F was also examined. Positive associations were evident between fluoride in drinking-water, fluoride concentrations in the bulk enamel and fluorosis selection. A significantly high inverse relationship was evident between t he fluoride concentration of the drinking-water and the subsurface enamel m icrohardness. In similar fluoride-concentration drinking-water areas of Ind ia and Israel the microhardness of the subsurface enamel was less for the I ndian teeth. The microhardness of the enamel near the DEJ for the three dif ferent water fluoride-concentration areas was not significantly different.