Hello! Uneven tooth arrangement can relieve the crowded teeth through the extraction interval, so that the number of teeth can be coordinated with the bone mass, so that the teeth can be arranged neatly on the dental arch and a good occlusal relationship can be established; Patients with crowding degree II-III are more likely to have their teeth extracted. If the teeth are not extracted and the dentition is barely arranged, the orthodontic effect will be unstable and it will easily relapse into the original crowded malocclusion.