Whether orthodontics need to extract teeth, can not be generalized, if there is a serious extrusion of the teeth, or teeth large caries, serious anterior protrusion, back teeth occlusal relationship needs to be extracted; without the above circumstances, generally do not need. The main cases that need to be extracted are: 1. Severe extrusion of teeth: the teeth appear to be badly aligned, extruded teeth are not neat, and need to be extracted to provide space for overcrowded teeth to be aligned. 2. Teeth with large caries: teeth with large caries will affect the function of the teeth and need to be extracted. 3. Severe anterior protrusion: Teeth with severe anterior protrusion, which can be seen on the side of the lips do not protrude, need to remove the teeth, retract the front teeth and lips, and adjust the occlusal relationship. 4. Bad occlusal relationship of the back teeth: bad occlusal relationship of the back teeth will cause the efficiency of chewing to decrease, and you need to extract the teeth to adjust the occlusal relationship of the upper and lower teeth. Orthodontic treatment needs to go to a regular medical institution, according to the specific circumstances under the guidance of the doctor to decide whether the need for tooth extraction.