Treatment Of The "Underbite" Orthodontists refer to the underbite as a prognathic lower jaw (mandible) or as a retrognathic upper jaw (maxilla). In layman terms this is a case where the upper teeth are behind the lower teeth (anterior crossbite).    Before Phase I Treatment Crossbite - the upper teeth fit inside the lower teeth After Phase I Treatment Crossbite has been corrected These cases are best treated at an early age because once the bone sutures develop and close, the upper jaw cannot be moved forward as easily. Upper jaw moves forward at suture locations Treatment usually involves a reverse-pull headgear attached to an upper expansion appliance.    Reverse Pull Headgear in place. Before Using The Reverse Pull Headgear    After Using The Reverse Pull Headgear    Some patients still require orthognathic surgery (jaw surgery) even after wearing the reverse pull headgear. Notice how the upper teeth and upper lip have moved forward. Underbite Corrected Without Surgery       Back to top