ROOT CANAL DISINFECTION: THE ROLE OF PHOTOSENSITIZERS AND PHOTODYNAMIC THERAPY IN ENDODONTICS

Background. The success of endodontic treatment depends on the complete elimination of microbial flora from the complex root canal system. Conventional irrigants (sodium hypochlorite, chlorhexidine, EDTA) have significant limitations, including cytotoxicity, inability to completely eradicate biofilms, and difficulty of delivery to hard-to-reach areas, which necessitates the search for additional disinfection methods, one of which is photodynamic therapy (PDT). Subject. Modern methods of endodontic disinfection: conventional irrigants (sodium hypochlorite, chlorhexidine, EDTA), their activation techniques (ultrasonic, laser), and photodynamic therapy as an adjunctive approach. Objective. To conduct a systematic analysis of current data on the effectiveness of root canal irrigation, to evaluate the role and potential of photodynamic therapy as an adjunctive method of endodontic disinfection based on Russian and international studies of the last decade. Methodology. A systematic search of scientific publications was performed in the eLibrary, Cyberleninka, RSCI, PubMed, Scopus, Web of Science, and Cochrane Library databases over the last 10 years using keywords related to endodontic disinfection and photodynamic therapy. After applying inclusion and exclusion criteria, 40 sources were selected for analysis. Results. Conventional irrigants have limited efficacy against biofilms (Enterococcus faecalis, Candida albicans), are cytotoxic, and lose activity in deep dentinal layers; activation methods improve cleaning but do not ensure complete sterilization. Photodynamic therapy, based on the activation of a photosensitizer by light with the generation of reactive oxygen species, selectively damages multidrug-resistant pathogens without inducing resistance. The review presents a classification of three generations of photosensitizers and describes activation sources (laser and LED systems). Conclusion. Photodynamic therapy is a promising adjunctive method of endodontic disinfection that is optimally applied at the final stage of treatment to eliminate residual infection in hard-to-reach areas of the root canal system. The implementation of PDT is clinically and economically justified as it reduces the risk of recurrence, retreatment, and tooth loss.