Teeth should be on the front teeth over the lower front teeth, if the lower front teeth wrapped around the upper front teeth, the lower jaw protrudes forward, the middle of the face is sunken, that is, anti-mandibular, commonly known as “heavenly”. Anti-mandibular is a more common type of malocclusion, the best corrective period is at the age of 2 to 5 years old, under the guidance of the doctor, wear orthodontic appliances, correct bad oral habits and other simple methods of correction, generally 3 to 6 months to complete the correction. However, teeth replacement may occur after the replacement of teeth, if it occurs, the need for a second orthodontic treatment. However, at this time, most of the teeth are only anti-mandibular, and it is relatively easy to correct them. If the replacement teeth are not corrected in time, the permanent teeth are usually corrected after the age of 12, then more complex orthodontic appliances are needed, which is difficult, long and expensive, and the improvement of the face shape is not obvious. Severe cases have to wait until the patient is an adult to take orthodontic – orthognathic combined treatment to correct. Classification of the circumcision: (1) Odontogenic – often manifested as simple anterior teeth anti-collision, small anti-coverage, molar relationship is neutral or the beginning of near-medium relationship. The shape and size of the lower jaw are basically normal, there is no obvious abnormality in the relationship between the upper and lower jaws, the chin is not protruding or obviously protruding, and the face is basically normal. The mandible can recede on its own to the anterior teeth to the edge relationship. (2) Bone origin – anterior teeth are anticlosed with large anticovert. The molar teeth are nearly mesial malocclusion; accompanied by jaw deformity, which can be manifested as obtuse mandibular angle, long mandibular body, short mandible, underdevelopment of the anterior part of the maxilla, obvious protrusion of the chin, and the mandible often fails to recede on its own, with a concave facial shape. Sometimes it is accompanied by open-close deformity. (3) Functional – the mandible is excessively protruding or protruding forward and the anterior teeth are anticlosed, but the shape and size of the mandible are basically normal, and the mandible can be retreated to the anterior teeth are anticlosed or shallowly overlapping relationship.