There is no age limit for orthodontics. Usually in the deciduous dentition of 3~6 years old, the front teeth are malocclusion and oral habits are bad. At this time, early intervention and correction are needed, usually around 4 years old, and children will be more cooperative at this time. 7~ 12 years old, the tooth changing period is relatively complicated, so it is difficult to predict and judge their growth and development. Therefore, during this period, it is mainly to correct the disharmony between the upper and lower jaws, the dislocation of teeth that hinder their growth and development, and bad habits. For young people with less wear of healthy teeth, the orthodontic goal is the same as that of conventional orthodontics in the initial stage of permanent dentition. But for the elderly with different degrees of oral lesions, both function and health should be paid attention to. Considering both aesthetics and stability, at the same time, due to the influence of adults' occupation, the aesthetics and comfort of the appliance for treatment time are highly required, so you can choose a personalized treatment plan according to your own situation. Adults and children can correct it, and even people in their fifties can do orthodontics. But compared with minors, there are still some differences. Because of age, the facial development and alveolar bone development of adults have ended, so adulthood is not the best time for treatment, which also leads to a long treatment time and a long time to wear retainers in the later stage. Generally, the best age for orthodontics is 12- 18 years old, when the alveolar bone is in the best development age. At this time, orthodontics will use the growth and development ability of teeth to move teeth and rebuild alveolar bone to achieve the best effect and ensure the perfect orthodontic effect. It is not necessary to wear a retainer for too long after the end of late orthodontics, so this age is the best orthodontic age.