PRODUCTION OF GRADED MOTTLING IN MOLAR TEETH OF RATS BY FEEDING OF POTASSIUM FLUORIDE

¹ Indiana University School of Dentistry, Indianapolis, Indiana, and School of Medicine and Dentistry, The University of Rochester, Rochester, New York

1. The time periods covered by the formation of the fixed dentition of the rat is reviewed in this paper and the data checked by observing the effect of fluorine feeding upon the teeth.

2. A method is presented for the experimental production of fluorosed enamel in the molars of the rat using as a basis observations made on a group of 43 Wistar strain animals that were given graded doses of potassium fluoride for varying lengths of time immediately following birth. The results show that it is possible to produce mottling by the feeding of fluorine to young rats during the period of appositional growth and calcification of their permanent teeth. A mild type of mottling can be produced by using doses as low as 150 p.p.m. The optimal amount for mild, uniform mottling is 300 p.p.m. Concentrations varying from 350 to 550 p.p.m. produce macroscopic hypoplasia with pitting and corrosion. With high doses and extreme toxicosis, the enamel shows extensive softening and it is common for the dentin to become denuded soon after eruption of the teeth. The health of the animal likewise is affected adversely as manifest by an increased mortality in such a group. Sex did not seem to be a factor in altering the susceptibility of fluorine effects as manifest in the teeth.

3. Because mottled teeth are known to be high in fluorine content, the value of using experimentally fluorosed rat molars in studying the mechanism of action of this drug in preventing dental caries is made possible by this study.