The effect of sorbitol on the microbiology of the dental plaque in monkeys ( Macaca irus)

Abstract

A group of 4 monkeys was fed an essentially sucrose-free diet containing approximately 1 g/day sorbitol. The animals were infected with plaque from a cariesactive monkey and the population of Streptococcus mutans in plaque was determined over a period of weeks. A further group of 4 monkeys with an already established population of Strep. mutans in plaque was also fed a sorbitol-containing diet. The results obtained suggest that sorbitol will neither aid the implantation nor support the continuance of populations of Strep. mutans in plaque. All eight monkeys were included in experiments to determine whether adaptive processes occurred in the plaque microflora during prolonged consumption of sorbitol. pH measurements were carried out using antimony micro-electrodes and the number of sorbitol-fermenting organisms in plaque monitored over a 2-yr period. The capacity of plaque to produce acid from sorbitol remained unaltered during the experimental period and no increase in the numbers of sorbitol-fermenting organisms was noted. Large amounts of plaque were present in the sorbitol-fed monkeys but only one animal developed two small carious lesions after 3 yr consumption of a sorbitol-containing diet. Each of six control, sucrose-fed monkeys developed caries with multiple extensive lesions during the same period. The results suggest that long-term consumption of sorbitol is unlikely to induce the formation of plaque capable of the rapid fermentation of sorbitol to low pH values.