Microbe infection is not only the key pathogenic factor of primary endodontic infectious diseases, but also the arch-crimina of endodontic treatment fail. Therefore, the endodontic treatment success is based on the debridement of infectious root canal, elimination of bacteria, and the prevention of endodontic reinfection. It is beset with difficulties to control the endodontic infection in clinic because of the bacterial variety, anatomic complexity of root canal, and limitation of the root canal therapeutic methods. In order to get the ideal prognosis of the root canal treatment, in the procedure of the therapy, it should be the tight isolation of tooth, reasonable choose of the root canal preparation technique, rational use of root canal preparation instrument, effective irrigation of root canal, proper root canal dressing, and the 3-dimensional obturation of root canal.
