The Role of the Oral Microbiome in Periodontal Disease: A Systematic Review of Microbial Associations and Therapeutic Implications.

Periodontitis is a chronic inflammatory disease driven by bacterial pathogens. This meta-analysis aimed to quantitatively assess the association between nine bacterial strains and periodontitis across 11 studies. We extracted odds ratios (ORs) and 95% confidence intervals (CIs) from studies evaluating Streptococcus mutans, Lactobacillus, Fusobacterium nucleatum, Prevotella intermedia, Staphylococcus aureus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola. Heterogeneity was evaluated using Cochran's Q and I2 tests. We systematically searched PubMed, Scopus, and Web of Science up to March 2024, following PRISMA guidelines, to identify studies investigating the association between oral bacterial species and periodontitis. Porphyromonas gingivalis was identified as a significant risk factor for periodontitis in all eight studies (ORs: 4.17-97, I2 = 85.99%). Tannerella forsythia (ORs: 2.75-36.88, I2 = 85.39%) and Treponema denticola (ORs: 3.12-24.5, I2 = 85.54%) were also significantly associated with periodontitis. Prevotella intermedia showed a significant association in three out of four studies, despite high heterogeneity (I2 = 79.82%). Fusobacterium nucleatum and Staphylococcus aureus were not found to be significant risk factors. Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola are key bacterial risk factors for periodontitis. The findings highlight the importance of microbial screening in clinical practice, while the heterogeneity suggests the need for standardized research. Future studies should focus on longitudinal assessments and microbial interactions.