Effects of High Fluoride Intake on Utilization of Dietary Calcium and on Solubility of Calcified Tissues

Abstract

Male rats were fed, beginning at weanling age for 56 days, a diet in which the Ca was labeled with radiocalcium (Ca45). Animals of the control group received distilled water and those of the experimental group were given distilled water containing 50 ppm of fluoride. Chemical and radioactive analyses of the bones and incisor enamel and dentin allowed the calculation of the fraction of total Ca present in these tissues derived from the diet. Dry fat-free samples of calcified tissues were employed to determine the amount of Ca dissolved in acidic buffer solutions. The utilization of dietary Ca, involving absorption, transport and deposition of Ca by growing bones and teeth of rats was not affected by a high fluoride intake or by a high fluoride content tissues. The retention and turnover of the Ca originally present in the calcified tissues was not affected by the same circumstances. The skeletal tissues and the enamel and dentin of higher fluoride contents consistently allowed a lesser amount of Ca to be dissolved by weakly acidic buffer solutions than did the corresponding tissues of lower fluoride contents.[long dash]Authors.