Mandibular advancement is a procedure used to bring the lower jaw forward, correcting a jaw positioned too far back relative to the upper jaw. This treatment is sought for both functional and aesthetic reasons. Functional improvements include correcting a misaligned bite for better chewing, reducing strain on the temporomandibular joint, and significantly improving obstructive sleep apnea by opening the airway. Because changing the jaw position involves complex skeletal and dental structures, professional guidance from an orthodontist or maxillofacial surgeon is necessary for safety and effective results.
Understanding Jaw Recession
The condition addressed by mandibular advancement is retrognathia, a skeletal discrepancy where the lower jaw (mandible) is underdeveloped or set back. This position typically results in a Class II malocclusion, or overbite, where the upper teeth significantly overlap the lower ones. Retrognathia makes the recession of the chin and jawline more apparent when viewing the individual’s profile. Causes are multifactorial, stemming from genetic inheritance that dictates jaw size and shape. Environmental factors in childhood, such as prolonged thumb-sucking or chronic mouth breathing, can also negatively influence jawbone growth. This misalignment can lead to functional problems, including difficulty chewing, increased risk of dental trauma, and potential strain on the jaw joints.
Non-Invasive Approaches for Mandibular Positioning
Non-invasive approaches focusing on muscular and postural training, such as “mewing,” have gained popularity, particularly on social media. Mewing involves consciously maintaining proper tongue posture against the roof of the mouth, which proponents claim can reshape facial bones. This concept is part of the controversial theory of orthotropics, suggesting facial growth can be guided by external factors. However, there is a lack of rigorous scientific evidence that tongue posture alone can induce meaningful skeletal change in adults whose growth plates have fused. The biomechanical forces generated by the tongue are considered too weak to restructure a mature jawbone, and attempting self-correction without professional oversight carries risks like bite misalignment or temporomandibular joint dysfunction.
Orthodontic and Appliance-Based Correction
Treatment for Growing Patients
For patients who are still growing, orthodontists utilize specialized functional appliances designed to encourage forward mandibular growth. Devices like the Herbst Appliance or the Mandibular Anterior Repositioning Appliance (MARA) are fixed to the teeth and use telescoping mechanisms to hold the lower jaw in a forward position. By applying continuous, gentle orthopedic force, these appliances aim to stimulate growth at the jaw’s growth centers. This treatment is ideally performed during the patient’s pubertal growth spurt, helping the lower jaw grow into a more balanced relationship with the upper jaw.
Treatment for Mature Patients and Sleep Apnea
For skeletally mature patients with minor discrepancies, traditional orthodontic treatment can still achieve correction by modifying the dental alignment to camouflage the skeletal issue. Braces or clear aligners are frequently used in combination with Class II elastics, which exert a continuous pull to advance the lower teeth relative to the upper teeth. This method primarily shifts the position of the teeth within the jawbones (dentoalveolar change) rather than significantly changing the bone structure itself. Separately, Mandibular Advancement Devices (MADs) are custom-made oral appliances used by adults to treat mild to moderate obstructive sleep apnea. Worn only during sleep, these appliances hold the mandible and tongue forward to prevent airway collapse, providing a functional advancement for breathing, not a permanent structural correction.
Surgical Solutions for Skeletal Advancement
When jaw recession is severe and the patient is skeletally mature, orthognathic surgery is the definitive treatment. The most common procedure for advancing the lower jaw is the Bilateral Sagittal Split Osteotomy (BSSO). During this major surgery, the surgeon makes cuts inside the mouth, splitting the lower jawbone behind the molar teeth. The tooth-bearing segment of the mandible is then moved forward and secured with small titanium plates and screws. This surgical repositioning permanently corrects the skeletal discrepancy, improving both bite alignment and facial profile.
Orthognathic surgery often requires 12 to 18 months of pre-surgical orthodontics to align the teeth so they fit together correctly once the jaw is moved. A genioplasty, or chin surgery, is frequently performed concurrently to enhance the projection of the chin tip, though this procedure only addresses aesthetics and not the overall bite. Recovery involves a post-operative period of soft-food consumption, typically four to six weeks, while the bone heals.