1. If your dental arch is too small to hold so many teeth, there will be crowded teeth and uneven arrangement. At this time, if you want to get enough space to correct your teeth, you must reduce the number of teeth.

2. Retract the anterior teeth between tooth extraction, improve the protrusion of dental arch and improve the face shape. For example, some people's lips are protruding. After tooth extraction and correction, the protruding amount of lips will become smaller and the face will become beautiful.

3. Adjust the occlusal relationship of the posterior teeth through the extraction interval, so that the posterior teeth are staggered, the occlusal contact area is the largest, and the best chewing efficiency is achieved.

But not all orthodontics requires tooth extraction, depending on the patient's specific situation. There are three situations that require tooth extraction:

1. Patients with crowded dentition. This kind of patients, because of the mismatch between tooth quantity and bone quantity, cause tooth deformity, so a certain number of teeth must be pulled out during orthodontics to coordinate the relationship between tooth quantity and bone quantity, relieve dentition crowding and reduce the recurrence of deformity.

2. Patients with prominent faces. This kind of patients need to pull out a certain number of teeth to get a gap, to achieve the purpose of retracting the front teeth and moving the back teeth, to alleviate facial protrusion, so as to make the patient's facial profile more beautiful.

3. Patients who need to correct the occlusal relationship. Because of the asymmetry of upper and lower teeth, this kind of patients need to extract teeth to adjust the occlusal relationship.