Effects of partial sugar restriction for 6 weeks on numbers of Streptococcus mutans in saliva and interdental plaque in man.

Abstract

Twenty 17-year-old schoolchildren were selected for the study because of high salivary counts of <i>Streptococcus mutans</i> ( > 10⁶ CFU/ml) and a frequent intake of sugars between meals. After a baseline determination of the numbers of <i>S. mutans</i> and lactobacilli in saliva, and of <i>S. mutans</i> in interdental plaque, the subjects were asked to avoid sugar-containing between-meal products, e. g. sweets, chewing gum, soft drinks and confectionery, and to eat a maximum of 4–5 meals/day. After 6 weeks of sugar restriction, the participants were allowed to return to their former food habits and were then followed for a further 6-week period. Seven subjects, also with high salivary counts of <i>S. mutans</i> and a frequent sugar consumption, served as control group. The results showed a statistically significant decrease of mean salivary <i>S. mutans</i> counts from 1.5 × 10⁶ to 0.3 × 10⁶ CFU/ml (p < 0.001) during the sugar restriction period. The mean number of lactobacilli in saliva decreased from 2.3 × 10⁴ to 0.2 × 10⁴ CFU/ml (p < 0.001). Regarding the interdental plaque samples, the number of tooth surfaces with detectable <i>S. mutans</i> were reduced from 52 to 32% (p < 0.001). When the subjects returned to their former food habits, the <i>S. mutans</i> and lactobacillus values almost reached the baseline level again. No obvious changes were found in the control group for any of the studied variables. To conclude, the 6-week period with sugar restriction reduced the number of <i>S. mutans</i> both in saliva and in interproximal spaces. Also the lactobacillus counts in saliva decreased.