The document discusses common endodontic mistakes related to access, instrumentation, and obturation including treating the wrong tooth, ledge formation, perforations, separated instruments, and over/under filled canals. It provides details on causes, recognition, correction, and prevention of each mistake to help endodontists avoid errors and improve treatment outcomes. The document emphasizes the importance of careful diagnosis, conservative access preparation, adhering to principles of instrumentation, and optimizing obturation quality.