Nutritional Delivery of Probiotics for Pediatric Caries Prevention: A Systematic Review

Background Dental caries is a biofilm-mediated disease strongly modulated by dietary sugars. Ingestible probiotics have been proposed as adjuncts to established pediatric prevention strategies. This systematic review evaluated whether probiotics delivered through foods or oral nutritional supplements improve caries-related microbial, salivary, biofilm, and clinical outcomes in children and adolescents. Methods Scopus, PubMed, ScienceDirect, and Web of Science were searched for studies published from January 2021 through 11 July 2026. Randomized controlled trials (RCTs) and controlled pediatric intervention studies using probiotic milk, yogurt, powder (for oral ingestion), drops, tablets, chewables, or lozenges were eligible. Topical-only products, adult-only studies, animal studies, and in vitro studies were excluded. Risk of bias was assessed using Joanna Briggs Institute critical appraisal tools, and findings were synthesized narratively. Results Ten publications representing nine independent studies were included; reported sample sizes across the nine studies totaled 726 participants. Food-based interventions produced short-term reductions in plaque or salivary Streptococcus mutans, but follow-up lasted only 7–14 days and incident caries was not assessed. Supplement-based interventions showed mixed effects. A 12-month probiotic-drop trial did not reduce recurrent caries. A larger trial reported lower selected caries-increment scores for a lozenge combining probiotics with arginine and xylitol, although surface-level outcomes from the same trial were not statistically significant. The evidence was limited by small samples, short follow-up, methodological concerns, and heterogeneity in strains, doses, delivery forms, comparators, duration, and outcome definitions; meta-analysis was not appropriate. Conclusions Nutritionally delivered probiotics may improve selected short-term surrogate outcomes, but current evidence does not establish consistent probiotic-only prevention of pediatric dental caries. Longer, adequately powered trials using standardized products, validated lesion-based endpoints, and direct head-to-head comparisons between food-based and supplement-based probiotic delivery are needed. Registration This review was not registered.