[Micromorphology of dentine in rats with chronic exposure to ammonium fluoride]

Wistar rats were exposed chronically to ammonium fluoride in a toxicological chamber where the concentration of fluoride ions was 0.0016 mg/m3 of air. The exposure lasted 6 hours daily five times weekly. The animals were sacrificed after 3.6 and 9 months of the experiment. Histological preparations were made from upper incisors with surrounding tissues. Microscopic examination demonstrated striation of dentine in the teeth, of these animals, which was due to development of decalcification bands. This type of changes was observed also by other authors and it is regarded as a characteristic feature of dentine damage by fluorine compounds.