Root canal treatment, also called nerve extraction, involves the removal of the pulp (nerve extraction), followed by the preparation and disinfection of the root canal into a certain shape, i.e. the thin root canal is slowly enlarged with a root canal file, and then flushed with a medicinal solution to remove tissue debris and bacteria from the inner wall of the root canal and to form a certain shape. After the clinical symptoms have subsided, the final step is the filling of the root canal, which is usually done with a paste-like agent with a maleic cement tip to fill the canal to the right length and width, and the crown part is filled with a temporary material. The crown is then filled with a temporary material. The crown is then filled. Currently, there is no ideal drug or method to restore the infected and damaged pulp to a healthy state once it is infected. The most mature and thorough treatment method, which is currently the mainstream method in the international endodontic community, is root canal therapy. In particular, root canal therapy is the only treatment option for teeth with residual crowns that require pile crown restoration in the prosthodontics department. As long as the root is not particularly curved, the root canal is clear, and the mouth opening is normal, root canal treatment is basically possible. What is usually not well known about root canal treatment is that: (1) root canal treatment is not always done in one visit. Doctors often perform the treatment in steps according to the patient’s clinical examination. Generally speaking, root canal treatment can be completed in 2-4 visits. If there is an uncontrolled infection or a large treatment response the number of treatment sessions will need to be increased. (2) The cost of root canal treatment is relatively high. Because of the complexity of root canal treatment, the doctor must be familiar with the anatomical knowledge of tooth structure and skilled operation techniques, and special root canal treatment instruments and equipment and materials are required. (3) There may be complications after each root canal treatment: the most common ones are pain and swelling, which are mild and will disappear the next day. Severe ones require anti-inflammatory treatment, but do not affect the final outcome. (4) Not 100% successful. For curved root canals and calcified root canals, success is often not obtained due to anatomical reasons, and even broken needles may occur in individual patients. (5) Take 3-4 pictures. In the process of root canal treatment, doctors often ask the affected tooth to take X-ray before, during and after the root canal treatment to help diagnose, understand the location of the pulp chamber and the number and shape of root canals, measure the working length of the root canals and provide a basis for comparison in future follow-up and evaluation of the treatment effect. (6) It is best to add a full crown after surgery. The teeth after root canal treatment are more brittle and it is recommended to perform crown restoration after surgery to prevent the tooth from fracturing and prolong the life of the tooth.