Root canal treatment includes several steps such as root canal preparation, root canal disinfection, root canal tightening and 3D filling, etc. The conventional treatment cycle takes 2-3 weeks and requires 2-3 follow-up visits during the treatment period. However, in clinical practice, root canal anatomy is simpler and the extent and degree of lesion is smaller, so one-time root canal treatment can be performed. There is no statistical difference between the success rate of one-time root canal treatment and multiple root canal treatments in the medical literature. However, in the clinical process, the time of treatment and the number of follow-up visits should be selected according to the difficulty of the root canal anatomy and the extent of the lesion.