Methods of Evaluating Tin and Fluoride Salts as Anticaries Agents in Animal Caries Experiments

¹ Miami Valley Laboratories, The Procter & Gamble Company, Cincinnati, Ohio

The anticaries effectiveness of stannous chloride, stannous fluoride, and of sodium fluoride was investigated by administering the materials at low concentration in the water or by topically applying these materials at several concentrations and frequencies. If a material is unstable, such as stannous chloride or stannous fluoride, topical application was the method of choice so that concentrations of application at realistic levels could be effectively controlled. With topical applications at equivalent low concentrations of fluoride (0.1 per cent SnF₂, 0.05 per cent NaF), SnF₂ was found to be more effective than NaF. At high concentrations, however (2 per cent and 8 per cent SnF₂, 2 per cent and 4 per cent NaF), these two materials were about equal in their caries reducing effect in rats. Stannous chloride applied topically at 2 per cent was ineffective. Stannous fluoride supplied at 10 ppm fluoride in drinking water was markedly superior to sodium fluoride at at the same fluoride concentration while stannous chloride at a similar concentration of Sn(II) to stannous fluoride was ineffective.

The frequency of application of topically effective agents was an extremely important variable in determining caries progression. The more frequent the application, the more effective the caries reduction was found to be.

There was an individuality of response of the first, second, and third molar to the application of anticaries agents. Stannous chloride, stannous fluoride, and sodium fluoride were most effective on the third molar.