Reduction ofStreptococcus mutansby probiotic milk: a multicenter randomized controlled trial

Objective To investigate the effects of probiotics,Lactobacillus paracaseiSD1, on the quantities ofStreptococcus mutansin saliva and plaque samples of preschool children. Design This randomized trial recruited 487 preschool children from eight childcare centers. Participants were assigned to receive a 6-month course of placebo milk daily (group I), probiotic milk either daily (group II) or three days a week (triweekly, group III). The absolute quantities ofS. mutansand total lactobacilli in the saliva and plaque samples at baseline (T0), after intervention (T6), and 6 months after discontinuation (T12) were assessed by qPCR. Results Of 487 children, 354 completed all follow-up periods. However, only 268 children (3.2 +/- 0.8 years old; groups I = 86, II = 89, and III = 93) provided adequate saliva for qPCR. Whereas the quantities ofS. mutanswere significantly decreased in groups II and III compared to group I in the saliva and plaque samples at T6 and T12, those of total lactobacilli were significantly increased (p< 0.0167). There was no difference in the quantities ofS. mutansor total lactobacilli between groups II and III at any period. Significant changes in the quantities ofS. mutansand total lactobacilli lasted until T12 compared to T0 (p< 0.0167). Conclusions Probiotic administration daily or triweekly reducesS. mutansquantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children.