Effects of a carbohydrate-free diet and sugar substitutes on dental plaque accumulation.

Plaque accumulation and characteristics were determined gravimetrically, planimetrically, visually, and microbiologically in 24 human subjects who consumed a carbohydrate-free diet for 4 days. In addition, the effects of xylitol-, sorbitol- and sucrose-containing candies upon plaque formed during consumption of the diet were ascertained. Experimental design was such that all 24 subjects traversed each 4-day test period; a 9-day interval between test periods was observed. All plaque measurement methods demonstrated that the subjects in all groups, including a control group which received no candies, accumulated significant amounts of dental plaque. No significant differences in plaque amount could be detected among the xylitol, sorbitol and control groups. However, subjects receiving sucrose-containing candies clearly exhibited larger amounts of plaque. The bacteriological investigations corroborated the clinical observations. The number of microbial colonies from plaque samples taken from the sucrose test group was clearly higher than in the other three groups. In addition, the number of bacteria in plaque samples from the sorbitol group was higher than in the xylitol group. A statistically significant increase in the proportion of anaerobic sorbitol- and xylitol- fermenting bacteria was detected in the sorbitol and xylitol test groups during the 4-day test periods.