Root canal treatment is one of the more complex endodontic treatment items, which usually requires 2-3 treatments, with an interval of one week each time, and the whole root canal treatment takes about 20 days to complete, and each clinical operation takes about one hour. Root canal treatment is mainly divided into three steps: 1, the necrotic infected tooth tissue is completely removed, the pulp cavity is opened, the pulp nerve inactivator is sealed in the pulp cavity, and the second follow-up is performed after a week. 2, the root canal is enlarged manually or mechanically, flushed and disinfected, and the root canal is filled with calcium hydroxide type anti-inflammatory drugs. 3, the root canal is filled with a vertical pressure filling method using dental cement tip and hot dental cement. The root canals were filled tightly by using the vertical pressure filling method of the adhesive tip and hot glue.