Role of Enterococci faecalis in failure of Endodontic treatment

The resident microbial flora in the oral cavity typically contains 10 bacteria (Mims et al., 2005). However, only 150 microbial species have been isolated and cultured from root canals. The endodontium is a sterile cavity and the invasion of oral microbes to establish infection is by the penetration to enamel and dentine and overcome the host responses (Bergenholtz, 1974). Although all the bacteria in the oral cavity can invade the root canal, only a few microbes have been identified in infected root canals (Miller, 1994; Sundqvist, 1994; Wilkins et al., 2003). Endodontic infections with Enterococcus faecalis are probably not derived from patients own microflora, which indicates that in these infections Enterococcus faecalis is of exogenous origin (Vidana et al., 2011).