First of all, please be clear: there is no necessary connection between orthodontic treatment and age, and it is not the case that orthodontic treatment can no longer be performed as you get older. The orthodontic treatment is closely related to the periodontal condition, and orthodontic treatment for patients with severe periodontitis without periodontal disease control will aggravate the loosening of teeth or even lead to tooth loss. A relatively helpless phenomenon is that, due to the lack of attention to oral hygiene in our population, the periodontal condition tends to get worse and worse as we grow older, thus depriving many patients of the opportunity of orthodontic treatment. So what are the characteristics of adult orthodontic treatment? First of all, the rate of alveolar bone remodeling is lower in adult patients than in adolescents, and tooth movement is correspondingly slower, so the course of treatment is longer than in adolescent patients. In addition, adult patients cannot undergo growth reshaping treatment to take advantage of their growth potential, but require orthodontic masking treatment or combined orthodontic-orthognathic treatment. For example, receding jaws in adolescent patients in the early permanent dentition can be guided forward with functional orthodontic treatment, while adult patients require surgical treatment to improve the jaw position. Secondly, adult patients have more oral diseases than adolescent patients, such as dental caries, periodontal disease and even missing teeth. These problems will complicate orthodontic treatment for adult patients, or even make orthodontic treatment impossible. A thorough intraoral examination and evaluation should be performed prior to orthodontic treatment and appropriate periodontal treatment should be completed. Gingival recession may occur in adult patients after orthodontic treatment, especially in patients with crowded teeth and a large difference between the width of the cervical and incisal margins, and a “black triangle” may appear in the anterior region, which affects the aesthetics to a certain extent. In addition, many patients have high aesthetic requirements and ask whether they can undergo invisible orthodontic treatment. At present, lip-side fixed orthodontic technology is more mature, while invisible orthodontics is an emerging technology, the indications are relatively narrow, can only be used for relatively simple cases, for complex cases orthodontic effect is not very ideal. Patients should choose an orthodontic treatment plan under the guidance of an orthodontist according to their own situation.