Non-cariogenicity of the disaccharide palatinose in experimental dental caries of rats.

The caries-inducing activity of palatinose (isomaltulose, alpha-D-glucopyranosyl-1,6-fructose) was examined in in vitro and in vivo experiments, comparing it with other carbohydrates. When Streptococcus mutans was successively subcultured in a broth medium containing 1% palatinose, the strains belonging to serotype a, d, or g did not ferment palatinose, whereas the strains belonging to serotype b, c, e, or f did ferment palatinose. Furthermore, palatinose significantly inhibited the synthesis of insoluble glucan from sucrose by S. mutans. Specific-pathogen-free rats which had been infected with S. mutans 6715 and fed a diet containing 56% palatinose did not develop significant dental caries. However, rats infected similarly, but fed a diet containing sucrose, glucose, fructose, or a glucose-fructose mixture manifested significant caries when compared with the noninfected, sucrose-fed control rats. Furthermore, it was found that replacement of half of the sucrose content with palatinose resulted in decreased caries development compared with caries development in rats fed the sucrose diet.