Penetration of microorganisms into the pulp is the main reason for endodontic treatment and failure to eliminate them is the main cause of failure of endodontic treatment. Microorganisms attached irreversibly to substratum and form biofilms in the root canals. These biofilms are heterogeneously composed. This article discusses the role of biofilms and how to eliminate them.

Keywords: Biofilms; Endodontics; Microorganisms.