Residual effects of fluoride on a severe cariogenic challenge in rats.

The influence of temporary dietary restriction with and without fluoridated drinking water on the progression of caries was studied in 60 desalivated Sprague-Dawley rats. Dietary restriction alone had little effect on caries progression when the challenge was interrupted and then resumed, in contrast to the effects of dietary restriction plus fluoride. Animals subjected to gavage plus fluoride in the drinking water for 11 days developed significantly less severe lesions on their lingual surfaces than did any of the other groups. No significant differences were observed in the microbial flora of the animals at the end of the study. The results show that temporary dietary restriction alone has little permanent effect on caries progression and that fluoride administered even for a short time in the absence of cariogenic challenge has a statistically significant, but probably less than optimum, protective effect against a subsequent caries challenge.