Changes in the structure of dentine from cheek teeth of deer chronically exposed to high levels of environmental fluoride.

The purpose of this study was to examine, using backscattered electron imaging, the changes occurring in the structure of the dentine including giant tubules in the teeth of deer chronically exposed to fluoride. The primary and secondary dentine was characterised by the presence of interglobular dentine and regular bands of hypo- and hypermineralised dentine. Giant tubules in the unworn teeth of animals exposed to low and high levels of fluoride were characterised by a large lumen and hypermineralised rim in which there were calcospherites. With the occlusal wear of the teeth tubules beneath the immediate surface of the exposed dentine in teeth from fluorotic animals became occluded with mineral, but in low fluoride animals some tubules at the surface were not occluded with mineral. It is suggested that mineral which occludes the tubules may come from both intrinsic and extrinsic sources. The presence of some open tubules at the immediate surface in the worn teeth of animals exposed to low fluoride suggests an extrinsic source for this mineral.