The main goal of root canal treatment is to eliminate the infection in the complex root canal system for the long-term success of root canal treatment. Proper debridement of the root canal system, especially in the extra-canals and hidden canals, is essential for successful root canal treatment. Therefore, clinicians must have a thorough knowledge of the anatomy of the root canal system and its variations. Recognizing the root canal anatomy and extra-canals determines the different strategies to be used in cleaning, shaping, and obturation to achieve the best result of root canal treatment. The recent diagnostic aids as CBCT , usage of magnification as microscope and development of the instrumentation system improves the treatment outcome for clinicians and patients. This lecture aimed to discuss prevalence, identification and instrumentation of extra-canals with its influence on success/failure of Endodontic treatment.
