Pre- and Post-Eruptive Effect of Sodium Fluoride on Dental Caries in the Syrian Hamster

¹ U.S. Department of Health, Education, and Welfare, Public Health Service, National Institutes of Health, National Institute of Dental Research, Bethesda, Maryland

Protection against dental caries in the hamster third molar was associated with a post-eruptive rather than a pre-eruptive effect of F^-.

Ten p.p.m. of F^- administered in the drinking water continually from weaning or only during the post-eruptive period of the third molar prevented the formation of carious lesions in every third molar of hamsters affected with rampant dental caries during a period of 35 days that this tooth was observed in the mouth. In control animals consuming only distilled water, cavitation destroyed over 60 per cent of every third molar crown.

When the fluoride was consumed in water, intubated, or injected only during the pre-eruptive period of third molar tooth formation severe dental caries uniformly occurred within 35 days after its eruption.

If 10 or 50 p.p.m. of F^- in drinking water was discontinued 2 weeks after eruption of the third molar and the animals were given distilled drinking water for the remaining 21 days, only partial residual protection was noted.

Under the experimental conditions employed, wherein 10 p.p.m. of F^-was tested in drinking water, an acidulated solution of NaF containing 0.1 molar phosphate did not show a greater cariostatic effect than a neutral NaF solution without phosphate.