Jaw Surgery, also called orthognathic surgery, is surgery to fix your upper jaw (maxilla) and/or your lower jaw (mandible) when they don’t line up. Jaw surgery can be used to remedy severe orthodontic problems involving the relationship between the teeth and jaws, including the correction of under bites (the most frequent surgical correction) and congenital abnormalities (birth defects) related to jaw development. It can even help alleviate sleep neap, a potentially life-threatening condition.