Not every patient who undergoes orthodontic treatment needs to have his or her teeth extracted. The orthodontic orthodontic treatment process whether to extract teeth, what kind of teeth to extract, and how many teeth to extract is a prudent decision to be made by the orthodontist based on a clinical examination and model analysis, and a comprehensive consideration of all factors. The orthodontic extraction treatment has its rigorous physiological basis, mainly in the following aspects: First of all, in the process of human evolution, the gradual degeneration of the masticatory organs in the jawbone, muscles, alveoli and teeth are unbalanced, resulting in the relatively large amount of teeth and relatively small amount of bone. In addition, under the impression of environmental factors or oral habits, the bone volume of our teeth is relatively smaller than our tooth volume, such as fine and soft diets, lack of chewing function stimulation, resulting in dental and jaw bone dysplasia or poor oral habits cause the upper and lower arch or arch malformation, etc. are in need of orthodontic treatment. In general, orthodontic extractions have several purposes, the first of which is to relieve the crowdedness and alignment of our teeth. The second purpose is to move the front teeth back and improve the lateral appearance of the overjet. In addition, orthodontic extractions can also coordinate the upper and lower dental arches to obtain a better bite between the upper and lower teeth.