The influence of diet on the growth of streptococcal bacteria on the molar teeth of monkeys (Macaca fascicularis).

The rates of regrowth of bacteria in developmental grooves on these teeth were determined. Plaque was removed from palatal grooves up to 96 h after cleaning and the number of bacteria and of individual streptococcal species were determined; Streptococcus sanguis, Streptococcus mutans and Streptococcus mitior were the major ones. In monkeys fed one of three different diets, the numbers of each species reached stable levels 18-24 h after tooth cleaning. The median doubling times of the streptococcal population were 4.69, 3.82 and 4.25 h for two maintenance diets and a sucrose diet, respectively. The median doubling times of individual species ranged from 2.01 to 4.38 h and appeared to be independent of the composition of the various diets. There was no difference in the number of bacteria in 18 h-old plaque from discrete sites in fed or fasted monkeys, nor in the numbers of streptococci, except that the size of the Strep. mitior population increased significantly with fasting. Thus host-derived substrates, possibly salivary components, may be used by plaque bacteria and support their on growth in developmental grooves in the absence of food.