The second permanent molar needs to be repaired after extraction, the role of the second permanent molar in the dental column is crucial, and it should be repaired as soon as possible after extraction, otherwise it will lead to displacement of neighboring teeth, elongation of the opposite teeth, food inclusions, etc., as follows. 1. Displacement of neighboring teeth: there is a supporting role between neighboring teeth in the dentition, after the extraction of the second permanent molar, the first permanent molar loses its support, and will be loosened and dislocated. 2. Elongation of the opposite teeth: after the extraction of the second molar, the opposite teeth of the second molar will gradually elongate after losing its occlusal contact, and the gums in the missing teeth area are often damaged and ulcers appear due to chewing food. 3. Food impaction: Due to the displacement of the neighboring teeth and the elongation of the opposite teeth, both the neighboring teeth and the opposite teeth may lose their normal occlusal contact, resulting in food impaction. It is recommended to go to the hospital in time.