The microbial communities of the root canal and dental sulcus systems in patients with asymptomatic chronic apical periodontitis: A Cross-Sectional Study

BACKGROUND: The current data on the microbiome in chronic apical periodontitis is based mainly on culture-based methods, which have a low sensitivity and cannot fully identify anaerobic bacteria. At the same time, the mechanisms and risks of pathogen cross-translocation between the root canal and gingival sulcus in patients with periodontal disease are poorly understood. This study aims to address this gap by conducting a comparative analysis of these two biotopes.

AIM: Using highly sensitive methods of molecular genetic analysis, we aim to identify and compare the species composition of microorganisms colonizing the root canal and dental sulcus in patients with chronic apical periodontitis.

METHODS: A single-center prospective case-control study included 170 patients. Samples from root canals and gingival sulci of the same teeth were collected with sterile paper points under rubber dam isolation. Real-time PCR was used to assess detection rates, microbial loads (Ct values), and bacterial associations. Statistical analysis involved chi-square, Fisher’s exact, Mann-Whitney U, and Student’s t-tests (α=0.05).

RESULTS: Root canals showed higher prevalence of E. faecalis (83.5% vs. 16.5%, p<0.001), strict anaerobes (97.1% vs. 39.4%, p<0.001), and polymicrobial associations (82.9% vs. 72.9%, p=0.021). A key finding was the strong association of E. faecalis with Actinobacteria (55.3% vs. 6.5%, p<0.001) and Fusobacterium nucleatum (46.1% vs. 4.0%, p<0.001). Microbial loads were significantly higher in root canals; for example, Ct values for E. faecalis were 22.1 vs. 28.7 (p<0.001).

CONCLUSION: The root canal microbiota in chronic apical periodontitis differs qualitatively and quantitatively from that of the gingival sulcus. It is dominated by E. faecalis within complex anaerobic communities, highlighting the need for targeted disinfection protocols in endodontic treatment.