ABSTRACT
Endodontic infection is caused by microorganisms colonizing as surface aggregates in the root canal system. These complex microbial communities are called biofilms that harbours numerous microorganisms with altering ecological requirements and pathological potential. The root canal system's intricacy and unpredictability, along with the multi- species nature of biofilms, make disinfection extremely difficult. The primary goal of endodontic treatment is to eliminate the biofilm from the root canal walls which is responsible for endodontic infection. The most important factor for failure of root canal treatment is the persistence of microorganisms as bioflms in the root canals. Eradication of biofilm is made possible by specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms along with microbial killing. The aim of this narrative is to review the mechanisms of biofilms' formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms and the role of root canal disinfectants on biofilm removal.