Which type of bacteria is commonly found in failed root canal treatments?

The type of bacteria commonly found in failed root canal treatments is Enterococcus faecalis. This bacterium is a resilient and opportunistic pathogen that can survive in harsh conditions, making it particularly adept at thriving in the complex environment of the root canal system. Its presence is often associated with persistent infections despite prior treatment efforts, as it can form biofilms and has a high degree of resistance to conventional endodontic therapies.

In the context of endodontics, Enterococcus faecalis has been extensively studied and identified as one of the primary microorganisms implicated in root canal failures. Its ability to withstand various antimicrobial agents and its persistence in contaminated root canals contribute to the difficulty in effectively eradicating it during the endodontic treatment process.

While other bacteria listed, such as Streptococcus pneumoniae, Bacteroides fragilis, and Porphyromonas gingivalis, are significant in different contexts—such as respiratory infections or periodontal diseases—they are less frequently associated with the specific complications arising from failed root canal treatments compared to Enterococcus faecalis.