Nerve necrosis is a common disease that occurs in the dental tissue, most of the causes are due to bacterial infection, which is caused by the caries stage is not treated in time, and the further infection of bacteria causes pulp tissue infection, which will cause nerve necrosis after a long time. It may also be caused by the trauma of the tooth, the tooth is hit by the sharp external force, and the stress is transmitted to the pulp tissue causing the nerve necrosis. Once the nerve is necrotic, it should be treated promptly, otherwise it may cause damage to the apical area, and in serious cases, it may also cause interstitial infection, which is a facial swelling, and the treatment of nerve necrosis is related to the closure of the apical foramen of the tooth. If the apical foramen is already formed in the permanent tooth, the root canal treatment can be carried out directly, if it is a young permanent tooth whose apical foramen has not been developed, apical induction molding is needed.