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Updated: Jan 1, 2026
Individualized Reconstitution of Human Milk Microbiota: A Feasible Approach in Real-World Settings
Published on: February 7, 2025
Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial
Chanika Manmontri1,2, Areerat Nirunsittirat2,3, Supatcharin Piwat4,5
1Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, 50200, Thailand.
Insights
Probiotic milk containing Lactobacillus paracasei SD1 reduced Streptococcus mutans and increased beneficial lactobacilli in preschool children. These positive effects on oral microbiota persisted for at least six months after the intervention ended.
Area of Science:
- Microbiology
- Pediatric Dentistry
- Nutrition
Background:
- Dental caries is a prevalent issue in preschool children, often linked to Streptococcus mutans.
- Probiotics offer a potential strategy for modulating oral microbiota and preventing caries.
Purpose of the Study:
- To evaluate the impact of Lactobacillus paracasei SD1 on Streptococcus mutans and total lactobacilli levels in preschool children's saliva and plaque.
- To determine the duration of these effects post-intervention.
Main Methods:
- A randomized controlled trial involving 487 preschool children over six months.
- Participants received daily placebo milk, daily probiotic milk, or triweekly probiotic milk.
- Quantitative PCR (qPCR) was used to measure bacterial quantities at baseline, post-intervention, and six months after discontinuation.
Main Results:
- Probiotic milk consumption (daily or triweekly) significantly decreased S. mutans and increased total lactobacilli in saliva and plaque compared to placebo.
- These microbial changes were sustained for at least six months after the probiotic intervention ceased.
- No significant differences were observed between daily and triweekly probiotic administration.
Conclusions:
- Regular intake of Lactobacillus paracasei SD1 in milk effectively reduces S. mutans and enhances lactobacilli in young children.
- This probiotic intervention demonstrates potential for long-term caries prevention in preschool populations.
- The observed benefits on oral microbiota are durable, persisting well beyond the intervention period.
Objective:
To investigate the effects of probiotics, Lactobacillus paracasei SD1, on the quantities of Streptococcus mutans in 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 of S. mutans and 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 of S. mutans were 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 of S. mutans or total lactobacilli between groups II and III at any period. Significant changes in the quantities of S. mutans and total lactobacilli lasted until T12 compared to T0 (p < 0.0167).
Conclusions:
Probiotic administration daily or triweekly reduces S. mutans quantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children.
Clinical Relevance:
Daily or triweekly consumption of L. paracasei SD1 supplemented in milk may help prevent dental caries in preschool children.
