Orthodontic treatment is possible at the age of 40 when periodontal tissue health is ensured. Orthodontics (clinically known as orthodontic treatment) is one of the routine treatment programs in dentistry, which is mainly used to treat symptoms such as abnormal chewing function or facial shape caused by crooked and irregular teeth; its principle is to make use of the plasticity of the alveolar bone, i.e., the alveolar bone will be altered under the action of orthodontic corrective force, which will make the teeth move in order to achieve the purpose of orthodontic treatment. Therefore, at the age of 40, if the periodontal tissues (generally referred to as the alveolar bone) are healthy and the teeth are not pathologically loose, orthodontic treatment can be carried out; however, due to the relatively older age, the orthodontic process will be relatively complicated and the orthodontic cycle will be relatively prolonged.