The first step in root canal treatment is routinely root canal preparation, and in severe cases, opening the pulp chamber for drainage. Root canal therapy is a routine treatment for endodontitis periapical. If the pulp tissue is not completely necrotic, the decayed tooth tissue is removed under local anesthesia, and the top of the pulp chamber is removed to expose the root canal opening. After the pulp is removed, root canal preparation is performed to enlarge and shape the root canal in preparation for root canal filling. If the acute stage of periapical periodontitis is combined with interstitial infection, the first step is to open the pulp for drainage, and in severe cases, systemic anti-infective treatment is also required. The routine steps of root canal treatment are root canal preparation, root canal disinfection, and root canal filling. Therefore, the first step of root canal treatment is to prepare the root canal, which is the foundation for root canal filling, and to open the pulp and drain the pulp in case of interstitial infection. You can go to the stomatology department.