Hello! The step of tooth shaping is 1, and the crowded teeth are arranged by using the extraction gap. Patients with crowding degree II-III are more likely to have their teeth extracted. 2. Retract the front teeth by using the extraction gap to improve the protrusion of dental arch and improve the face shape. For example, some people have protruding lips. After tooth extraction, the protrusion of lips will become smaller and the face will become beautiful. 3. Adjust the occlusal relationship of the posterior teeth by using the extraction interval, so that the posterior teeth are staggered and the occlusal contact area is the largest, and the best chewing efficiency is achieved. The cost is related to many factors, and the fees of each hospital are different.