Abstract
Background/Objectives: Streptococcus mutans (S. mutans) is a primary cariogenic bacterium contributing to biofilm acidogenicity and enamel demineralization. Conventional caries prevention relies mainly on mechanical plaque control and dietary modification, but probiotics have emerged as potential adjuncts for oral microbiota modulation. This pilot randomized controlled trial aimed to evaluate the short-term effects of a multi-strain probiotic containing Lactobacillus and Bifidobacterium on clinical and microbiological parameters associated with dental caries in children. Methods: A double-blind, randomized, placebo-controlled clinical trial was conducted in 40 children aged 6-14 years from a community setting. Participants were randomly allocated (1:1) to receive either probiotic or placebo lozenges for 30 days. Clinical assessments included the Gingival Index (GI), Plaque Index (PI), International Caries Detection and Assessment System (ICDAS), salivary pH, buffering capacity, and salivary S. mutans concentration. The study was preregistered (10.17605/OSF.IO/GKVUW) and ethically approved. Results: The intervention was well tolerated, with no adverse events reported and high participant acceptability. Despite there being no statistically significant differences in any clinical or microbiological parameter (p > 0.05), we found trends toward higher salivary pH, improved buffering capacity, and reduced S. mutans counts in the probiotic group. Conclusions: Short-term probiotic supplementation was safe and well accepted among children but did not produce statistically significant improvements in oral health parameters over 30 days. These findings highlight the feasibility of probiotic use in pediatric populations and support the need for larger, longer-term trials to clarify their potential role as adjuncts in caries prevention.