Root canal therapy is the best way to treat pulpitis and periapical inflammation. Root canal treatment mainly includes root canal preparation, root canal disinfection and root canal filling. 1, root canal preparation: root canal preparation mainly includes removal of root canal contents and flushing of the root canal. Generally, the main flushing drug is 5.25% sodium hypochlorite solution and 3% hydrogen peroxide solution, and root canal shaping is also done to remove the infected material in the root canal. 2, root canal disinfection: root canal disinfection is generally done with drugs. The main purpose is to stop the pain, control the exudate in the root canal, and induce the development of the root tip. The commonly used root canal disinfectant is calcium hydroxide paste. 3. Root canal filling: Root canal filling is mainly to close the root canal of the tooth so that bacteria cannot enter the root canal system again and cause reinfection of the root canal. It is mainly used to fill the root canal by using dental cement tip and root filling paste. Root canal treatment is the most commonly used treatment for endodontic diseases, so once the symptoms of pulpitis and periapical infection appear, it is important to go to the hospital for root canal treatment in a timely manner. Only a proper root canal treatment can solve the tooth pain caused by endodontic disease and enable the tooth to remain in the mouth to perform its chewing function and preserve the tooth.