Whether the teeth need to be extracted or not, it needs to be decided according to the specific situation: 1. For uneven teeth, if the crowding is not very big in about 4mm, you can consider using the method of arch expansion, adjacent surface piece cutting, pushing the molar backward to solve the crowding; for patients with larger crowding, it is recommended to extract the teeth. Crowding is a disproportion between the amount of teeth and the amount of bone, i.e., the jawbone of a patient with crowding cannot accommodate many teeth, but the length and size of the jawbone cannot be changed through orthodontic treatment, and all that can be changed is the size of the teeth. In order to match the jawbone that cannot be changed, tooth extraction is needed for orthodontic treatment; 2. Whether tooth extraction is needed in addition to crowding irregularities, it also needs to be combined with the patient’s facial shape. If the patient only has mild crowding misalignment, but the mouth looks bulging and the teeth are more protruding, extraction orthodontic treatment will also be considered. In fact, tooth extraction is not terrible, after the extraction of teeth for orthodontic treatment, the gap between the extracted teeth has disappeared, the front and back teeth of the extraction sockets are leaning together, and it looks to others as if no teeth have been extracted, but the teeth have changed from crowded and uneven to neat and beautiful.