Morphological and physiological adaptations of microbes in root canal biofilms – A literature review

Abstract

Microbial flora in the oral cavity gain entry into root canals after pulpal exposure, either due to trauma or dental caries. Once inside the root canal, bacteria of different species organize into a network and communicate with each other to withstand the chemical and physical disturbances during the treatment. They cause extraradicular infections that do not respond to conventional endodontic therapies. Bacteria present on the surface of root canals organize into a framework consisting of the matrix, bacteria, and water. The matrix consists of extracellular polysaccharide, which varies with the species that secrete them. It also contains proteins, fatty acids, and extracellular DNA, which help in the growth of the matrix, survival, and pathogenesis of organisms. Microorganisms entering the root canals should survive the nitric oxide rich, oxygen stressed, and nutrient-deprived environment. They should also resist the chemical and mechanical disturbances created during endodontic treatment to enable their persistence in the root canals. This review aims to discuss biofilm formation and the mechanisms by which it helps in bacterial survival in root canals.