Tooth extraction in orthodontics is the most worrying thing for every parent, is there any harm in tooth extraction? Why do doctors pull teeth? Why do doctors extract teeth for orthodontics? We know that the goals of orthodontics are: 1) beautiful face; 2) beautiful teeth; 3) normal and stable contact between upper and lower teeth; 4) periodontal health. If the patient’s teeth are crowded more than a certain amount, the teeth protrude forward, the lip is forward, the lip can not wrap around the teeth, in these cases orthodontics need to extract the corresponding teeth to free up the position to align the teeth, or inward teeth, to achieve facial beauty and dental aesthetics. Is there any harm in tooth extraction? After detailed x-rays and model analysis, the doctor carefully chooses to extract the teeth for treatment and use the appropriate orthodontic force in orthodontics, which is a physiological process that is not harmful. On the contrary, crowded teeth, anteriorly protruding teeth cause abnormal occlusion of teeth and are prone to dental and periodontal diseases in the long run. So, is it a matter of pulling out the teeth that are not aligned, or pulling out a few teeth if you want? Tooth extraction is not so arbitrary, there are certain principles. The doctor has to choose the teeth that can solve the problem and are relatively the least important, and not just remove whoever is out of alignment. In the selection of teeth to be extracted, the doctor follows the following principles: try not to extract teeth; try to extract bad teeth (decayed teeth, loose teeth, badly formed teeth); try to extract teeth with little function; and extract teeth symmetrically on the top and bottom. Do not extract incisors because they have the greatest impact on the aesthetics. Do not extract cuspid teeth (tiger teeth), because cuspid teeth have a greater impact on chewing and fullness under the face. Do not extract the sixth-aged tooth. It is the most functional for chewing and extraction is only an option if it has been extensively damaged. The teeth that are routinely recommended for extraction are the two bicuspids behind the cuspids. The two contiguous bicuspids are similar in shape, and removing one leaves the other functional. Therefore, doctors often choose to extract one bicuspid on the top and one on the bottom.