Extraction orthodontics is one of the more commonly used methods in orthodontic clinics for the following reasons: 1) teeth are misaligned and crowded, and need to be aligned by extracting teeth to provide clearance; 2) teeth are protruding, and need to be extracted to improve the protrusion of the arch by internalizing the front teeth. For most cases of orthodontic extractions, the most commonly extracted teeth are preferred to bicuspids. In general, extraction of bicuspids has minimal impact on the morphology and function of the dental arch. In order to maintain a symmetrical alignment of the teeth after orthodontic treatment and to establish a good occlusal relationship between the upper and lower teeth, the teeth are usually extracted symmetrically from the upper and lower, left and right simultaneously. Many patients worry that the tooth socket will loosen after the extraction and that the teeth will be lost early in old age, which is actually an unnecessary worry. The stability of teeth depends on the health of periodontium, and many premature tooth loss originates from periodontal disease. The movement of teeth in orthodontic treatment depends on the reconstruction of the alveolar bone, and there is sufficient scientific evidence to support this.