In the deciduous and dentition periods, the general malocclusion, such as individual tooth dislocations, does not require treatment. However, for malocclusions that seriously impede the growth and development of the maxillofacial region, such as deciduous occlusion (commonly known as "ground", it will hinder the development of the maxilla and should be treated early. If the child cooperates, it can be treated at about 3 and a half years old. If the mandibular retraction is severe, early orthopedic treatment can be performed in the dentition period to block the serious development and reduce the difficulty for subsequent treatment. For most malocclusions, it is only after 12 years of age that the teeth are completely replaced. At this time, the adjustment of the occlusal relationship between the upper and lower jaws is basically completed, and a definite diagnosis of the malocclusion can be made, and the correction effect is easy to maintain stable. During this period of treatment, the treatment is short and the effect is good. If the patient misses this period, after entering the adult period, although the growth and development are basically completed, the alveolar bone reconstruction is slower than that of the adolescents, but the adult patients have better cooperation, and the normal orthodontic treatment can also obtain the ideal correction effect.