Comparison of the Cariostatic Effect of Topically and Systemically Administered Controlled-Release Fluoride in the Rat

Abstract

Rats treated continuously with topical fluoride from an intraoral delivery system (Intraoral Fluoride-Releasing Device) developed significantly fewer proximal, sulcal, and total carious enamel areas after 5 weeks on a caries-conducive regimen than did rats that received fluoride at a similar rate systemically from a subcutaneously implanted controlled-release delivery system. Rats treated with continual topical fluoride or with intermittent topical fluoride from drinking water had significantly fewer carious enamel areas on third-molar surfaces than rats treated with continual systemic fluoride. The findings suggest that the substantial cariostatic benefits produced by the intraoral fluoride-releasing device in rat caries trials were the result of topical effects due to the continual presence of fluoride in the oral fluids.

Fluoride and Pilocarpine Reduce the Risk of Caries Produced by Chronic Clomipramine Treatment in Rats

“…The fluo ride dose uses (10 ppm) produced a significant decrease (-20%) in the weight gain in the presence o f clomipramine. The mechanism of this fluoride effect in the clomipramine group is not known and previous studies using fluoride alone (10 ppm) have not described this effect [Mirth et al, 1985;Zdanowicz et al, 1989], Pilocarpine is an alkaloid that was first isolated from South American plants of the genus Pilocarpus. It functions as a muscarinic-cholinergic agonist and has potent effects on both smooth muscle and exocrine tissues.…”

“…Fluoride is the best-known and most efficient substance used to prevent dental caries in humans and animals. In rats, the concentration most frequently used for a control group is 10 ppm in drinking water [Larson et al, 1976;Mirth et al, 1985;Tamura et al, 1987;Tanzer et al, 1987;Zdanowicz et al, 1989], although small quantities of fluoride are enough to prevent rat caries [Beiraghi et al, 1989;Edgar et al, 1981]. Furthermore, caries induced by hyposalivation could be prevented by stimulating the secretion rate with a choli-nergic agonist drug.…”

Fluoride Administration during Enamel Formation and Its Effect on Dental Caries in Rats (Short Communication)

“…When the dose exceeded 3.0 mg F/kg body weight there was a posi tive correlation between the F dose and the caries score. This could well have been due to a resemblance between caries and enamel disturbances caused by F. In most of the previous caries experiments in rats the experimental diets contained more than 50% sucrose [Poulsen et al, 1976;Mirth et al, 1985;Hunt and Navia, 1975]. Our hypothesis that too high a sucrose content of the diet would mask a preeruptive effect of F was not confirmed, since the results neither showed an effect with the high nor the low sucrose content of the diet.…”

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The caries-prophylactic effect of systemic fluoride (F) supply has been questioned, in particular since several studies have failed to show any association be tween the F concentration in the enamel and the pre valence of caries [Fejerskov et al, 1981], Several ani mal studies have been unable to show an effect of preeruptive F supply on caries [Madsen and Ed monds, 1964;Navia et al, 1976;Poulsen et al, 1976;Mirth et al, 1985]. However, Hunt and Navia [1975] reported a preeruptive effect of F on buccal enamel lesions but not on sulcal caries.

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Effects of an Acidic Calcium Phosphate Solution and the Intraoral Fluoride-Releasing Device on Dental Caries and Fluoride Uptake in Rats

“…The IFRD is a small controlled-release delivery system that is designed to be placed in the mouth and to release fluoride 24 h a day [Mirth, 1987]. Studies have shown that the contin ual topical fluoride from this system can significantly decrease the incidence of experimental dental caries in rats [Mirth et al, 1983[Mirth et al, , 1985a and maintain ele vated concentrations of fluoride in the saliva of adults and adolescents [Mirth et al, 1982;Kula et al, 1987].…”