Caries Inhibition in the Rat by Water-Borne and Enamel-Bound Fluoride

Abstract

Osborne-Mendel rats 22–25 days of age were subjected to a 7-day precaries test period during which they were fed a high starch diet and drank distilled water containing no added fluoride or with 10, 50, 100 or 150 ppm fluoride as sodium fluoride. After this period, 36 animals from each group were provided with distilled water during a 56-day caries test period (fed diet 2000 and infected with Streptococcus mutans 6715). Fluoride content in the enamel was shown to be directly related to the level of fluoride in the drinking water during the initial 7-day exposure period, both at the end of this 7-day period of fluoride treatment and at the end of the caries test period. Caries development was inversely related to fluoride uptake in the enamel; animals which received 50 ppm or more fluoride developed significantly fewer carious areas than the controls. 36 additional animals from each pretest group were subjected to the same caries test challenge as above but in addition were provided with 10 ppm fluoride in the drinking water. Caries development in these groups was extremely low even though there was no increase in the fluoride content of enamel in animals drinking water containing 10 ppm fluoride during the caries test period. Fluoride provided prior to the caries test regimen conferred the most protection on the sulci, in contrast, fluoride provided during the caries test regimen had a more pronounced effect on the smooth surfaces and in addition had a greater overall effect.

Effect of Low-Level Fluoride and Caries Incidence in Rats (Short Communication)

“…At 1 ppm fluo ride, the reduction for proximal caries was 75%, for buccolingual caries 66, and for sulcal caries 24% (table 4). Our results parallel those of Larson et al [1976] who showed that the greatest effect of fluoride was on smooth surfaces (85-99%) with less effective ness in the sulci (51-95%).…”

“…Although there are numerous studies in rats on the effect of fluoride in caries reduction, the majority have utilized large concentrations of fluoride [Larson et al, 1976;Tinanoff and Camosci, 1984;Afseth et al, 1984]. Generally, the concentrations are greater than that recommended for human consumption; conse quently, the development of an adequate animal model has been lacking.…”

“…Our results did not conf.rm those find ings; however, those studies differ considerably from ours, especially in the technique used to recover S. mutans. Three studies [Englander and Keyes, 1966;Larson et al, 1976;Mirth et al, 1983] used animals, and microbial recovery was qualitative rather than quantitative. Our quantitative technique was more precise than those of previous investigators.…”

Effects of resin-based temporary filling materials against dentin demineralization

“…Fluoride in saliva has been reported to provide more protection against demineralization than enamel-bound fluoride. Even at low pH, fluoride ion in saliva would increase the saturation degree of fluoroapatite, contributing to the remineralization of teeth 26,27) . Strontium ion was also involved in the remineralization process of caries dentin 28) , and the remineralization effect was affected by concentration of fluoride ions when used in conjunction with them 29) .…”

Effect of NaF and SnF2in Drinking Water on Hamster Dental Caries (Short Communication)

“…Furthermore, very dilute solutions of SnF2, as in the present experi ment, may quickly lose soluble stannous ions [Heferren, 1963]. A low concentration of SnF2 (0.002%) was examined in the present experiment because higher con centrations of fluoride ions (10 ppm F* as NaF) have been shown to almost entirely eliminate rat caries [Larson et al, 1976] which would further hinder the possibility of observing differences between SnF2 and NaF.…”