Root Canal Therapy Root canal therapy is the most effective treatment for endodontics and periapical diseases. It involves the use of endodontic instruments together with chemical disinfectants to thoroughly remove infected or necrotic pulp tissue and other infected materials from the root canal; and the use of medications to tightly seal the root canal system to prevent the root tip from communicating with the outside world and to promote the healing of the apical lesion. Due to the complexity of the root canal system of the tooth, it is sometimes quite difficult to completely and tightly seal the root canal, therefore, there is a certain failure rate of root canal treatment of endodontics and periapical disease, and if it fails, apical surgery can be considered as appropriate. Root canal treatment usually requires 2 to 3 follow-up visits to complete, some of the following reactions during the treatment process is inevitable, and we hope that the patient understands and cooperates with us. Step 1: Pulp inactivation, which takes 7-10 days; or opening the pulp and draining it to relieve the emergency. The second step: root canal expansion and disinfection, need to seal the medicine for about a week, the treatment itself due to instruments and drugs stimulation, may induce acute inflammation caused by pain, can take anti-inflammatory painkillers. If the pain is severe, you should consult a doctor in time. Step 3: Root canal filling. Step 4: Permanent filling. After root canal treatment, the tooth will become brittle due to the loss of blood supply, or the defect is too large to be filled, and must be restored with a full crown or a full crown with a pile core, which is an important step to preserve the affected tooth for a long period of time, and should not be ignored.