Root canal treatment involves a number of steps including root canal preparation, root canal disinfection, and tight 3D filling of the root canal. The overall treatment cycle takes 2-3 weeks, with weekly follow-ups during the course of treatment. If the anatomical structure of the root canal is simple, the scope of the lesion is small, such as endodontic disease does not involve the root apex, as well as the patient’s personal needs and the doctor’s treatment time, a one-time endodontic treatment can be performed. However, in the case of complex root canal anatomy and large lesions, the treatment time can be extended appropriately. Statistical analysis showed that there was no significant difference in the success rate between one-time root canal treatment and multiple root canal treatment. Therefore, there is no strict time and frequency limit for root canal treatment.