Fluoride Action Network


Control rats on the basic diets employed developed normal or nearly normal incisor teeth. Rats on the same basic diets to which dried thyroid had been added developed incisor teeth that were markedly bleached due to a potentiation of the toxic action of the fluorine in the basic diet. Subcutaneous injections in rats of protamine zinc insulin greatly increased the food consumption as reported by MacKay and Callaway. An increment in fluorine intake equivalent to 0.0005% fluorine in the diet, produced by increased food intake, did not increase the bleaching of rat incisors.