Influence of dietary disaccharides on mouth microorganisms and experimental dental caries in rats.

Osborne-Mendel rats were inoculated with Streptococcus mutans at weaning, divided into 5 groups and fed cariogenic diets containing 56 per cent sugar either as sucrose, maltose, lactose or combinations of sucrose/maltose and sucrose/lactose. The number of Strep. mutans on molar teeth of rats fed the diet high in maltose was much lower than for any other group of rats (p less than 0.01). Although Strep. mutans levels were low for rats fed maltose, the incidence of carious lesions was similar to rats fed sucrose when the textures of the two sugars were similar. Although maltose does not support plaque formation, it is a fermentable carbohydrate which can provide, if microorganisms are present, an environment conducive to dental decay. The incidence of carious lesions was highest among rats fed lactose.