Abstract

Twenty-one-day old weanling albino rats were divided into paired control and experimental groups, both of which were given ad libitum supplies of rat cake diet and drinking water (fluoride ion content 0·2-0·3 p.p.m.). The drinking water of the experimental groups was supplemented by the addition of sodium flJioride to give fluoride ion concentrations of 10,
25′, 100, 250 and 500 p.p.m. Mter periods varying from 13 to 52 weeks paired control and experimental animals were killed and the femurs removed, dissected free of connective tissue and radiographed.

The breaking stress and deflexion of the femurs on bending were determined within 5 hr of removal by the method of Bell, Cuthbertson & Orr (1941). The bones were then ashed and their inorganic residue determined.

All animals thrived and there was no difference in the pattern of weight gain between the experimental animals and their controls, with the exception of those drinking 500 p.p.m. These animals soon developed toxic signs and all died within 1 week.

The results show that, in rats, consumption of drinking water with a fluoride ion content as high as 250 p.p.m. for up to 52 weeks has no effect upon the radiographic appearance, the breaking stress and deflexion pattern on bending and the ash content.

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