A recessed jaw, medically termed mandibular retrognathia, is a condition where the lower jaw sits further back than the upper jaw, often resulting in a receding chin and a severe overbite. This skeletal discrepancy is a common form of malocclusion, meaning the upper and lower teeth do not align correctly. While many people seek correction for aesthetic reasons, a recessed jaw can also cause functional issues, including difficulty with chewing, speaking, and potentially contributing to obstructive sleep apnea. The approach to correcting this condition depends heavily on the patient’s age and the severity of the underlying skeletal misalignment.
Professional Assessment and Diagnosis
Fixing a recessed jaw begins with a comprehensive evaluation conducted by a team of specialists, primarily an orthodontist and an oral and maxillofacial surgeon. The orthodontist focuses on aligning the teeth and dental arches, while the surgeon addresses the underlying bone structure when the misalignment is skeletal. This collaborative approach ensures the correction of both the bite and the facial profile.
The diagnostic process relies on advanced imaging to precisely map the craniofacial structures. Traditional X-rays and cephalometric analysis are used to measure the relationship between the skull, jaws, and teeth. Specialists utilize three-dimensional (3D) imaging techniques, such as Cone-Beam Computed Tomography (CBCT), which provides a detailed view of the hard and soft tissues. This precise 3D data allows the care team to determine whether the issue is primarily dental—meaning the teeth are misaligned—or skeletal—meaning the jawbone is positioned incorrectly or underdeveloped.
Non-Surgical and Growth Modification Treatments
For children and adolescents whose facial bones are still undergoing growth, treatment often focuses on guiding the development of the lower jaw. These non-surgical methods are most effective during the peak growth spurt, around the time of puberty. Functional appliances are a category of orthopedic devices designed to stimulate the forward growth of the mandible.
One common device is the Herbst appliance, a fixed apparatus cemented to the back teeth that uses metal rods and tubes to hold the lower jaw forward. By exerting a constant, gentle force, this appliance aims to encourage bone growth at the temporomandibular joint, increasing the length of the lower jaw over a period of approximately 8 to 14 months. The goal is to correct the skeletal discrepancy before the growth plates fully mature.
For adults with mild skeletal retrognathia who wish to avoid surgery, or for those with primarily dental misalignment, orthodontics can be used as camouflage treatment. This approach uses braces or clear aligners to reposition the teeth within the dental arches to mask the underlying jaw discrepancy. This involves moving the upper teeth backward and the lower teeth forward to achieve a functional bite, but it does not change the position of the jawbones. This option is limited to cases where the skeletal misalignment is not severe and the desired movement is relatively small.
Definitive Surgical Correction Procedures
When a recessed jaw is caused by a significant skeletal discrepancy in an adult whose growth is complete, definitive correction requires orthognathic surgery. These procedures physically cut and reposition the jawbones to achieve proper alignment and facial balance. The most common procedure for advancing a retrognathic lower jaw is the Bilateral Sagittal Split Osteotomy (BSSO).
During a BSSO, the surgeon makes incisions entirely within the mouth, accessing the mandible near the back molars. The bone is then split lengthwise on both sides and the front segment, which holds the teeth, is moved forward to the planned position. Titanium plates and screws are used to secure the bone segments in their new position. This process not only improves the facial profile but also corrects the bite and can help open the airway, often improving breathing function.
In some cases, the skeletal issue is confined to an underdeveloped chin point, or microgenia, rather than the entire jaw. For this, a genioplasty may be performed alone or as an adjunct to a BSSO. A sliding genioplasty involves cutting a small segment of the chin bone and sliding it forward, securing it with plates and screws to enhance the projection of the chin. Alternatively, for minor recession, a chin implant made of a biocompatible material can be placed, or dermal fillers may be used as a temporary, non-surgical alternative to add volume to the chin area.
Maintaining the Corrected Jaw Position
Following orthognathic surgery like a BSSO, the recovery timeline is structured into initial healing and functional recovery phases. Swelling and bruising are significant in the first week, often peaking within 48 to 72 hours, and a liquid or non-chew diet is required for the first six weeks to allow for initial bone healing. Patients can return to light activities and work within two to four weeks, though the bone segments take approximately three to six months to achieve a strong bond.
A component of the post-treatment phase is the retention protocol, which is necessary after both growth modification and surgical correction. After orthodontic treatment, a retainer is required to prevent the teeth from shifting toward their original positions. Similarly, after orthognathic surgery, the patient may need to wear a splint or elastics to maintain the new jaw position and train the muscles to adapt to the new alignment. Long-term monitoring by the orthodontic and surgical team is necessary to ensure the corrected jaw position remains stable over time, as minor skeletal relapse can occur, particularly in cases involving large advancements.