Microbiology of endodontic diseases: A review article

Abstract

Microorganisms play an unequivocal role in infecting root canal system. Endodontic infections are different from the other oral infections in the fact that they occur in an environment which is closed to begin with since the root canal system is an enclosed one, surrounded by hard tissues all around. The endodontic infections constitute almost 40—50% of the overall oral diseases. Pulpal and periapical pathology are the commonest debilitating form of oral disease with systemic implications. Bacteria detected from the oral cavity fall into 13 separate phyla, namely, Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Spirochaetes, Fusobacteria, Synergistes, SR1, TM7, Chloroflexi, Deinococcus, Acidobacteria, and Cyanobacteria. Microbes seeking to establish in the root canal must leave the nutritionally rich and diverse environment of the oral cavity, breach enamel, invade dentine, overwhelm the immune response of the pulp and settle in the remaining necrotic tissue within the root canal. During that time they have to compete in a limited space with other microbes for the available nutrition. As long as the enamel and cementum layers are intact, the pulp and root canal are protected from invasion, but loss of these structures by caries, cracks or trauma opens an avenue for penetration of bacteria through the dentinal tubules. From all the cases which report back with pain and infection after the endodntic therapy, it has been observed that E. faecalis is the most commonly found, with prevalence values reaching up to 90%.Other bacteria isolated in similar cases are streptococci P. alactolyticus, P. propionicum, F. alocis, D. pneumosintes, and D. invisus. This article gives an in-depth view of the microbiology involved in endodontic infections during its different stages.