The role of probiotics in preventing dental caries: a systematic review of clinical evidence

Background: Probiotics have emerged as a promising adjunctive strategy for oral health, particularly in the prevention of dental caries, a multifactorial disease driven by ecological imbalances in the oral microbiome. Methods: A systematic search of PubMed, Scopus, and Web of Science was conducted for studies published between January 2014 and January 2025, focusing on the use of probiotics for caries prevention in children and young adults. Clinical trials and observational studies were included, and a qualitative synthesis was performed based on the extracted outcomes. Results: Twenty-one studies met the inclusion criteria. Most clinical trials reported a significant reduction in Streptococcus mutans levels following administration of probiotic strains, particularly Lactobacillus paracasei, Lactobacillus rhamnosus, and Bifidobacterium lactis. Several studies also demonstrated a decreased incidence of new carious lesions and an improvement in salivary immune markers. However, a minority of studies found no significant effect, highlighting potential variability due to strain type, dosage, delivery method, and population characteristics. Conclusion: The current evidence supports the potential of specific probiotic strains to reduce cariogenic bacterial loads and contribute to caries prevention. Further standardized, long-term trials are needed to clarify the most effective formulations and regimens for clinical application.