If the tooth still hurts after treatment, oral radiographs should be taken to combine with the pain symptoms. If the irritation pain persists after the filling of deeper cavities, the original filling can be removed and the bottom of the cavity can be checked to see if pulp penetration occurs. If the pulp vitality is normal, calcium hydroxide can be used to pad the cavity and then repair the cavity. If the x-ray shows an exposed pulp angle, the pulp cavity needs to be ground open under local anesthesia and the pulp removed to complete the root canal treatment. In case of persistent pain in the tooth after root canal treatment, the occlusal high point on the surface of the filling object needs to be adjusted and ground to lower the occlusion appropriately. If the oral CT shows the presence of an overfilled object of more than 2 mm in the apical part of the tooth, an apicoectomy is required. If a hidden fracture or longitudinal fracture of the root occurs, the affected tooth must be extracted.