Dental caries and mutans streptococci in the proximal areas of molars affected by the habitual use of xylitol chewing gum.

The relationship between the caries status and the microbiological status [mutans streptococci (MS)] in the proximal areas of lower right and upper left molars was investigated in subjects of the Ylivieska xylitol study in Finland (1982-1985) in a cross-sectional follow-up in 1988. Those children who had used xylitol chewing gum regularly since 1982 showed significantly lower caries indices in 1988, including the proximal caries scores. The presence of MS (expressed in log10 colony-forming units) in the proximal areas studied was significantly lower in habitual xylitol consumers. Carious interproximal areas of all subjects had significantly higher total levels of MS than clinically and radiographically sound interproximal areas. The present study supports the idea of a close association between MS and dental caries, and shows that the total level of MS in the human dentition can be influenced by xylitol. It is likely that the long-term (between 1982 and 1988) habitual xylitol consumption had decreased the prevalence of MS in the interproximal areas of the present subjects and, subsequently, decreased the proximal and overall caries indices.