Not a miracle, not a myth: The role of probiotics in periodontal health.

BACKGROUND

As the understanding of periodontal disease has evolved, therapeutic strategies have increasingly shifted from pathogen eradication toward ecological modulation of the oral microbiome. Within this paradigm, probiotics have emerged as potential adjuncts for maintaining periodontal health by promoting microbial balance and modulating host responses.

OBJECTIVE

To summarize the historical development, definitions, and mechanisms of probiotics and to critically evaluate the current clinical evidence supporting their use in periodontal therapy.

METHODS

This narrative review examines the conceptual framework of probiotics in oral health, distinguishing them from related approaches including prebiotics, postbiotics, and synbiotics. Literature from randomized controlled trials and meta-analyses was reviewed to assess the clinical effectiveness of probiotic interventions in periodontal therapy and to explore their proposed mechanisms of action.

RESULTS

Probiotic effects are highly strain-specific and involve multiple mechanisms, including production of antimicrobial compounds, competition for ecological niches, inhibition of biofilm formation and quorum sensing, strengthening of epithelial barrier integrity, and modulation of host immune and inflammatory responses. Evidence from randomized controlled trials and meta-analyses, particularly those evaluating Limosilactobacillus reuteri strains, suggests that probiotics used as adjuncts to nonsurgical periodontal therapy can significantly improve clinical parameters such as probing pocket depth, clinical attachment level, and bleeding on probing. However, substantial heterogeneity in study design, probiotic strains, delivery systems, and follow-up periods limits the comparability and generalizability of findings.

CONCLUSIONS

Probiotics represent a biologically plausible and ecologically oriented adjunct in periodontal therapy. While current evidence indicates beneficial clinical effects, further standardized and long-term clinical trials incorporating advanced microbiome analyses (e.g., next-generation sequencing) are needed to clarify mechanisms, optimize formulations, and support personalized probiotic strategies in periodontal care.