A protruding chin, medically known as mandibular prognathism, occurs when the lower jaw extends forward past the upper jaw. This skeletal imbalance, a form of Class III malocclusion, significantly affects the facial profile, often resulting in an “underbite” appearance. Correction aims to improve both facial harmony and the functional alignment of the teeth (occlusion). Solutions range from minimally invasive, non-surgical adjustments to comprehensive surgical intervention that permanently alters the underlying bone structure. The choice of treatment depends on the severity of the skeletal discrepancy and the underlying cause of the protrusion.
Initial Assessment and Diagnosis
Fixing a protruding chin requires a precise understanding of the underlying skeletal and dental relationships. This initial assessment involves an orthodontist and an oral and maxillofacial surgeon working together to determine if the issue is primarily dental (misaligned teeth) or skeletal (jawbone position).
A cephalometric X-ray, a lateral view of the head, is used to measure the angular relationships between the upper and lower jaws, providing a quantifiable assessment of the skeletal discrepancy. Three-dimensional imaging, such as Cone-Beam Computed Tomography (CBCT), and digital scans are also used to create a virtual model of the patient’s anatomy. This imaging allows the team to plan the precise movement required to achieve an ideal profile and functional bite.
Non-Surgical and Camouflage Options
For mild cases of mandibular prognathism, or for patients who wish to avoid surgery, non-surgical camouflage options can improve the facial profile.
Orthodontic Camouflage
Orthodontic treatment, using braces or clear aligners, is the primary method of dental camouflage. The goal is to reposition the teeth within the jawbone to mask the skeletal discrepancy and achieve a proper bite relationship. This often involves moving the lower front teeth backward (lingual tipping) and sometimes the upper front teeth forward to compensate for the jaw size difference. While this corrects the dental occlusion, it does not change the size or position of the jawbone. Orthodontic camouflage is suitable only for patients with a smaller skeletal discrepancy, as excessive tooth movement can compromise the health of the surrounding gums and bone.
Cosmetic Camouflage
Cosmetic camouflage offers an aesthetic approach to visually balance the facial profile. This technique involves the strategic use of dermal fillers, such as hyaluronic acid-based products, in adjacent facial areas. Injecting filler into a recessed upper jaw, the pre-jowl sulcus, or the nose can subtly alter proportions to make the lower jaw appear less prominent. This is a temporary solution, with results lasting from several months to over a year, and it offers no functional correction to the bite.
Surgical Correction Procedures
When jaw protrusion is moderate to severe, or when the bite is significantly compromised, surgical intervention provides the most definitive and stable correction. The choice of procedure depends on whether the issue involves the entire jaw structure or only the chin tip.
Genioplasty (Mentoplasty)
Genioplasty, or chin surgery, is the procedure used when the dental occlusion is correct, but the chin bone itself is too prominent. The surgeon performs a sliding genioplasty by making an incision inside the lower lip to access the chin bone. A precise cut (osteotomy) is made through the chin bone, detaching a small segment at the tip.
This bone segment is then moved backward to reduce its projection and secured in the new position with small titanium plates and screws. This technique allows for three-dimensional control, enabling the surgeon to also adjust the chin’s height or width. Since the bone is repositioned, the results are permanent and focus solely on improving the aesthetic balance of the lower face.
Orthognathic Surgery (Jaw Surgery)
For cases where the protruding chin results from a misaligned bite (skeletal Class III malocclusion), orthognathic surgery is necessary to reposition the entire lower jaw. This procedure, known as a mandibular setback osteotomy, is performed entirely from inside the mouth, leaving no visible external scars.
The most common technique is the Bilateral Sagittal Split Ramus Osteotomy (BSSO). The jawbone is cut on both sides behind the last molar, allowing the entire lower jaw (mandible) to be set back to align properly with the upper jaw (maxilla). Once the jaw is in the correct position, it is secured with small titanium plates and screws. Orthognathic surgery is a comprehensive treatment that corrects the facial profile and establishes a stable, functional bite.
The Recovery Process and Long-Term Results
The post-treatment phase varies significantly depending on the extent of the correction.
Genioplasty Recovery
Genioplasty is less invasive, with most patients returning to non-strenuous work or school within seven to ten days. Swelling and bruising are most noticeable in the first week, but the majority subsides within two weeks.
Patients must adhere to a liquid or soft-food diet for several days to avoid placing stress on the healing bone and internal sutures. Numbness in the lower lip and chin is common due to nerve manipulation; it often resolves in a few weeks but can occasionally persist for several months. Final aesthetic results are visible after three to six months as residual swelling fully diminishes.
Orthognathic Surgery Recovery
Recovery from mandibular setback orthognathic surgery is more involved and requires a longer healing period. Initial recovery involves a hospital stay of one to two days for monitoring pain and swelling. A soft or blended diet is necessary for four to six weeks to allow the surgically moved bones to fuse completely.
Significant facial swelling can take two weeks to resolve, but the final facial contour may take up to four months to fully define. Long-term numbness in the lower face is more likely than with genioplasty, sometimes lasting six to nine months, or indefinitely. The results from both genioplasty and orthognathic surgery are permanent, providing a stable, life-long correction to the facial profile and bite.