Hello, ground bag is a kind of surgery that can be used for dental plastic surgery. The front teeth are also called "ground bone", which shows that the lower teeth bite on the outside of the upper teeth, and some people just turn their teeth upside down; Some people not only have malocclusion of teeth, but also have deformity of facial bones, which is called skeletal malocclusion. It is characterized by hypoplasia of maxilla-backward, overdevelopment of mandible-forward, which leads to depression in the middle of the face and crescent-shaped profile, which affects the appearance and function.