There are two possible cases: 1, tooth decay, due to the exposure of tooth roots or food embedment between two teeth will produce tooth decay. The tooth decay usually needs to grind out the decayed material and then carry out the filling of light-curing composite resin or filling with glass ion; 2, periodontal disease, and the periodontal disease is due to the plaque and calculus covering the tooth neck or the root of the tooth, and the root of the tooth may show yellowing and blackening. Periodontal treatment is usually required and the main treatment is scaling with an ultrasonic scaler and subgingival scaling. If the periodontal pockets are still deep after 6-8 weeks of observation, surgical periodontal treatment is required to restore the periodontal health, promote attachment, gum attachment and regeneration.