Microbiological Analyses of Subgingival Flora in Response to Probiotic Adjuncts to Non-surgical Periodontal Therapy: A Scoping Review

This scoping review aimed to map the subgingival microbiological analysis methods used in randomized controlled trials evaluating probiotics as adjuncts to non-surgical periodontal therapy (NSPT) and to summarize the microbial and clinical outcomes reported. A comprehensive search of PubMed, Scopus, and Web of Science from January 2008 to October 2025 identified nine eligible studies that employed culture-based techniques, PCR/qPCR, DNA-DNA hybridization, and 16S rRNA sequencing of subgingival plaque samples. Evidence suggests that probiotics may provide short-term, strain-dependent modulation of the microbiota, characterized by transient reductions in key periodontal pathogens and early improvements in inflammatory parameters. However, substantial heterogeneity in microbiological methods limits direct comparison across studies and contributes to uncertainty regarding long-term ecological and clinical effects. While probiotics appear to offer supportive benefits during the early healing phase following NSPT, persistent microbial stability, durable colonization, and sustained clinical advantages have not been conclusively demonstrated. Given the limited use of high-resolution sequencing techniques and marked methodological variability, current evidence remains insufficient to support routine clinical application. Future studies incorporating standardized ecological endpoints, extended follow-up periods, and advanced molecular analyses are essential to clarify the true clinical relevance of probiotic adjuncts in periodontal therapy.