1.Tooth cleaning, tartar removal, caries filling, and treatment of gingivitis. 2.Take whole mouth curved section film. 3.Extract the residual roots and loose teeth with no retention value. Since radiotherapy is needed in the short term, root canal and nerve killing treatment should be carried out cautiously, and the patient’s teeth should not be palliated as much as possible, so that radiotherapy can be timely and safe. If the affected tooth exists in the tumor area, it cannot be extracted.