ASSOCIATIVE INTERACTION OF ROOT CANAL MICROORGANISMS IN VARIOUS FORMS OF CHRONIC APICAL PERIODONTITIS

Subject. The microbial composition of the root canal contents in patients with chronic apical periodontitis was investigated, differentiated by the clinical course of the disease. Objectives. To identify and compare the microbial species composition in root canals of patients with asymptomatic and symptomatic chronic apical periodontitis, using highly sensitive molecular genetic analysis methods. Methodology. The study was conducted based on Yaroslavl State Medical University and Sodruzhestvo LLC. It was a single-center, prospective, case-control study that randomly divided patients with chronic apical periodontitis into two groups: asymptomatic (n=170) and symptomatic (n=130). Before endodontic treatment, the contents of the root canals were collected under sterile conditions using a cofferdam, an apex locator, and endocanal paper pins. DNA was isolated at an automated station and then analyzed for microorganisms using real-time polymerase chain reaction with specific reagent kits. To identify key pathogens, the detection rate of microorganisms was compared between the two groups using the Yates-adjusted χ² criterion and the exact Fisher criterion with a significance level of p < 0.05 for statistical analysis. Results. The polymerase chain reaction (PCR) method was used to detect microorganisms, allowing for the identification of even small species. Statistical analysis confirmed the significance of the differences between groups. The results showed that symptomatic patients have a higher detection rate of highly virulent pathogens, such as E. faecalis and F. nucleatum, and their synergistic association contributes to the formation of resistant biofilms. Asymptomatic patients, on the other hand, are dominated by streptococci and form a more balanced community. Conclusion. These findings open up new possibilities for personalized endodontic treatment based on a patient's microbiological profile.