Orthodontics helps to restore the shape and chewing function of the teeth and is generally harmless. But part of the population for orthodontics will appear gum recession, loose teeth, enamel demineralization and other sequelae. 1. Gum recession: If no attention is paid to oral hygiene after orthodontic treatment and periodontal disease exists, gum recession will occur during treatment. 2. Loosening of teeth: general orthodontic treatment is a normal orthodontic response to a slight loosening of teeth, will gradually ease. However, part of the population will be due to excessive root resorption, resulting in significant loosening of the teeth, which may affect the normal chewing function to a certain extent. 3. Enamel demineralization: the occurrence of this complication is also related to the oral health condition, mainly because plaque accumulates on the tooth surface near the aligner for a long time, so it will cause demineralization of enamel, and if the demineralization is serious, it will lead to caries or enamel stripping. In general, patients normally cooperate with the doctor for orthodontic treatment, there is no harm to health, so there is no need to worry too much. In summary, orthodontic patients need to strengthen the management of oral hygiene in their daily life and go to the hospital in time when any discomfort occurs.