The hesitation of patients or parents to extract teeth often interferes with the doctor’s determination of the orthodontic plan, and in some cases, even though they are reluctantly orthodontically treated with non-extracted teeth, the end result is very unsatisfactory, and in some cases treatment is not even possible without extraction. In fact, extraction orthodontics is very common in the treatment of orthodontics, about 65%, and even without orthodontic treatment, most people with poorly positioned wisdom teeth have to be extracted. Extraction orthodontics has withstood the test of clinical practice in the more than 100-year history of the development of the orthodontic discipline. In cases of severe crowding, anterior protrusion and some open dentition, anterior dentition, posterior locking dentition must be treated by extraction, if not extracted, the teeth will soon relapse back to the original deformity. The original aesthetically pleasing facial shape may become abrupt and unsightly, and some cases of anterior protrusions, retrusions, and openings may not be corrected. After the extraction of teeth there are gaps, these gaps are generally not used to set teeth, the doctor used to move the teeth to achieve the purpose of orthodontic treatment, after the completion of orthodontic treatment, most of the gaps will be completely closed. Yin Jiaqi, Department of Stomatology, Affiliated Hospital of Inner Mongolia University of Nationalities, therefore the gaps provided by tooth extraction are used to solve the following problems: 1, orthodontic crowding: when there is severe crowding of teeth, like a bus full of people, in a limited space, crowded together, inside and outside; go down a few passengers, you can neatly line up, when the front and back teeth are very crowded, it may be necessary to extract four bicuspids and four Wisdom teeth (third molar) 2, correction of facial protrusion: some patients have protruding teeth (bulging teeth), their lips cannot be closed, their face is abrupt and unattractive; by extracting teeth to gain clearance, the front teeth can be collected backwards, thus making the face beautiful. 3, correction of occlusal relationship: some patients have very aligned teeth, such as some open and anticlinal, and teeth are extracted to improve the chewing function; this situation is also very common to extract teeth. Tooth extraction has no effect on future eating: the main function of teeth is to chew, and some scholars have studied that the level of chewing function depends on the contact point of bite, not simply on the number of teeth. Normal bite when all the teeth are in close contact, while many malocclusion although the number of teeth (32) but many teeth bite not chewing function is very low; and by extracting teeth orthodontic treatment, adjust the bite relationship, although the number of teeth is less, left 24, but the bite contact is close, indicating that the chewing function has improved. In addition, a study has carefully calculated the area of the occlusal surface of the teeth and the distribution of occlusal forces and concluded that the removal of some teeth has no effect on masticatory function. Therefore, extraction of teeth for orthodontic treatment will not affect the oral function. Many patients have a fear of tooth extraction and are afraid of pain. Nowadays, many new anesthetics can make tooth extraction painless, and orthodontics can begin about a week after extraction.