Wisdom teeth, except for a few cases can be retained, most of them should be prophylactically extracted: 1, repeatedly cause pericoronitis (inflammation of wisdom tooth gums); 2, has decayed (worm teeth, tooth decay) or caused decay of adjacent teeth; 3, caused food embedment between adjacent teeth; 4, caused periapical infection, jaw bone cyst; 5, before or after orthodontic treatment, in order to prevent the front teeth to appear again crowded or malocclusion; 6. complete bone buried Obstructed wisdom teeth, although not connected to adjacent teeth, but have caused reflex pain, or other symptoms.