The microbial community of persistent endodontic infection and the use of root canal disinfectants against E. faecalis: In vitro and in vivo review

In cases of unsuccessful endodontic treatment, E. faecalis is commonly detected and remains popular among the scientific community for in vitro and in vivo research. The nature of the bacteria's predominance is dependent on the difficulty in cleaning the apical portion of the tooth and E. faecalis' capacity to grow deep into the dentinal tubules. The purpose of this review is to gather current research on root canal disinfection against E. faecalis. In this literature review, four databases were searched: PubMed, EBSCOhost, ScienceDirect, and Google Scholar, with explicit inclusion and exclusion criteria. The compiled review shows that a predominant multi-microbial community within a persistent root canal infection include Porphyromonas gingivalis, Fusobacterium nucleatum, and Enterococcus faecalis. E. faecalis produces moderate biofilms and causes infection through its virulence factors such as esp, cylA, ace, gelE, asa, and efaA. Several disinfecting agents and approaches have been explored for their capacity to eradicate E. faecalis and penetrate the dentinal tubules. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) gel eliminate E. faecalis and other resistant microbes such as Staphylococcus aureus, and Escherichia coli. Combing NaOCl irrigation with the following: Photon-induced photoacoustic streaming, passive ultrasonic irrigation, and diode laser irradiation, eradicates E. faecalis. The current research has shifted towards nanoparticles against E. faecalis because of its dissolution capacity, size, and antimicrobial efficacy. E. faecalis resists calcium hydroxide through its proton pump mechanism, but it is susceptible to Ca(OH)2 when applying a proton pump inhibitor or chlorhexidine.