Children can simply show that the front teeth are closed, the relationship between the rear teeth is normal, and there is no obvious abnormality in facial appearance. In severe cases, in addition to the malocclusion of the anterior teeth, the posterior teeth are near-middle malocclusion, facial l/3 hypoplasia and mandibular protrusion. The ground cover can be restored by correction, which requires consulting a doctor in a regular dental institution to make a correction plan.