Two types of plot days:
Osteogenic: due to genetic and disease factors, in addition to anterior crossbite, it often shows large overbite. Molar is almost malocclusion, accompanied by jaw deformity. It can be manifested as blunt mandibular angle, long mandible, short mandibular branch or underdeveloped anterior maxilla. The chin is obviously protruding forward, and the lower jaw often cannot retreat on its own. The face is depressed, sometimes accompanied by jaw opening deformity. It is difficult to correct, and the effect of simple orthodontic treatment may not be good.
Tooth development: mostly due to local obstacles in the process of tooth eruption or replacement, it is often manifested as simple anterior crossbite. The reverse coverage is small, and the molars are closed neutral or close to neutral. The shape and size of mandible are basically normal, there is no obvious abnormality in jaw, chin is not prominent, and face is basically normal. The mandible can retreat to the front teeth by itself. X-ray cephalometry has no abnormal morphological structure, easy correction and good prognosis.