Macroscopic Appearance, Microhardness and Microradiographic Characteristics of Experimentally Produced Fluorotic Lesions in Sheep Enamel

Abstract

Fluorotic lesions resembling those seen in human teeth were produced experimentally in the unerupted enamel of the central incisor teeth of 3 sheep by daily dosing for 21 days with 2, 4 or 6 mg fluoride/kg body weight. Opacities, both superficial and extending to the amelodentinal junction, horizontal lines and pits were seen on the specimens. A comparison between the sheep with the lowest and highest dosing showed that, at these fluoride levels and given for a relatively short period of tooth development, there was no clear correlation between fluoride intake and the type of fluorosis found. The opacities and the bases of the scattered pits showed consistently lower hardness values than the surrounding enamel and in addition, the mineral content of the opacities was significantly lower than that of the control enamel. These findings support the theory that fluorotic lesions may be both pre-eruptive or post-eruptive (traumatic) in origin.