Some Dental Effects of Xylitol under Laboratory and in vivo Conditions

Abstract

In vitro, xylitol was not fermented by S. mutans and A. viscosus and had no effect on cell growth. Xylitol neither interfered with the utilization of sucrose by the two bacterial species nor inhibited bacterial colonization of rat molar surfaces in sucrose-containing broth. In a rat caries test, xylitol added to starch diets and starch-sucrose diets did not affect formation of bacterial agglomerates on rat molars. Rinsing with 10% xylitol solutions did not interfere with early plaque formation in young adults consuming their habitual diet. Telemetric recordings of interdental plaque pH showed that 10% xylitol rinses and xylitol chewing gum were non-acidogenic. Xylitol did not prevent rapid sucrose glycolysis. In a 40-day rat caries test, xylitol was non-cariogenic and seemed to reduce the cariogenic potential of sucrose administered simultaneously, however, the animals consuming xylitol diets suffered from severe diarrhoea and gained less weight. In another experiment, rats drank less when xylitol was added to the drinking water.

Effects of Mouth Rinses with Xylitol and Fluoride on Dental Plaque and Saliva

“…However, these effects were explained by the lack of sucrose consumption rather than by specific effects of xylitol or sorbitol [Rateitschak-Plüss and Guggenheim, 1982]. Our results on plaque quantity are, on the other hand, in accordance with mouth rinsing experiments performed by Mühlemann et al [1977] and Paunio et al [1984], but contradict the recent findings of Lingström et al [1997]. In this latter study, there was no real placebo group included, and mouth rinsing was performed 15 times daily with a 50% xylitol solution, a regimen hardly feasible as part of an everyday prophylactic programme.…”

Effect of xylitol on growth of nasopharyngeal bacteria in vitro

“…No statistically significant inhibition of H. influenzae or M. catarrhalis growth was seen. The growth pattern of S. mutans was found to resemble that reported previously (13,16,18). The advantage of xylitol for caries prevention is well documented and is, for the most part, connected with a reduction in the growth of S. mutans.…”

“…In vitro growth of S. mutans NCTC 10449. One or 5% xylitol was added to the basic medium, resulting in growth inhibition similar to that reported previously (13,16,18). The symbols are the same as in Fig.…”

“…It has been shown that the anticariogenic effect of xylitol lasts for several years after the practice of consuming xylitol daily has been discontinued and is associated partly with the reduction in the total levels of S. mutans and partly with the decrease in the amount and adhesiveness of dental plaque (8). Some studies have failed to document any long-term decrease in the amount of S. mutans bacteria, however (13,19), and this has been explained by the selection of bacterial strains: habitual use of xylitol may select S. mutans strains which are up to 87% nonexpressive of the fructose phosphotransferase enzyme (17) and are thought to have lower adhesiveness to enamel and, therefore, lower virulence (7,12).…”

“…Adults can tolerate doses of up to 200 g per day (11) without symptoms, and children can tolerate 45 g per day (1). Most experiments have used xylitol concentrations of 0.5 to 6% (13,16,18). Caries prevention is achieved with doses of 4 to 20 g per day (6,14,15).…”