An Endodontic Treated tooth with Post operative Apical Periodontitis often is a result of improper BMP during Root Canal Treatment.

Only a small number of species of micro organisms have been found in the root canals of  properly endodonticaly treated teeth which in follow up revealed a persisting Asymptomatic periapical radiolucencies.

Micro organisms found in failed Root Canal Treated tooth

So in case of a failed Endodontic therapy it is easy to identify the micro organisms based on Culture methods as the number of species to suspect are very few.

The Micro organisms Genera found in Periapical regions of a Failed Endodontic treated tooth are:

  • Actinomyces
  • Enterococcus
  • Propioni bacterium (previously called as Arachnia)
  • Yeasts
  • Candida Albicans – Most commonly isolated Fungus

Enterococcus Fecalis – Most common pathogen in most cases of failed Endodontic Treatment.

Among the enterococcus Species the most commonly found is Enterococcus Fecalis which is given particular interest because it is “Rarely found in Untreated and Infected Root Canals”. This means that Enterococcus Fecalis is found alone in the Root canal and can live without help from other Micro organisms.

Enterococcus Fecalis can grow  as a mono infection in treated canals in the absence of Synnergistic support from other bacteria.

Therefore E. Fecalis is held to be a Recalcitrant (Stubborn) Microbe among the potential etiologic agents of post treatment apical periodontitis.