Teeth can be straightened at age 30 and can be improved with orthodontic treatment if diagnosed with malocclusion. Orthodontics can improve early contact and joint interference due to malocclusion, benefit the health of the teeth, alveolar bone and temporomandibular joints, as well as facilitate daily cleaning and maintain the health of periodontal tissues. The characteristics of adult orthodontics are different from those of adolescent orthodontics because the growth and development of adults have stopped, so the whole orthodontic process takes longer. In addition, adults tend to suffer from other oral diseases, such as periodontitis, pulpitis, residual roots and crowns in the mouth, etc. The design of orthodontic program will also be more complicated. It is recommended to visit a hospital and receive regular treatment with the help of a doctor.