Orthognathic surgery, commonly known as jaw surgery, is a procedure designed to correct significant misalignments between the upper jaw (maxilla) and the lower jaw (mandible). This procedure is not merely cosmetic; it changes the underlying bone structure to ensure the teeth and jaws meet correctly, improving function and overall health. While orthodontic treatments like braces move teeth within the existing bone structure, jaw surgery is reserved for cases where the skeletal components themselves are disproportionate.
Visible Signs and Functional Symptoms
The first indication that jaw surgery may be needed often comes from difficulties experienced in daily life or visible changes to the face. Chronic pain in the jaw joints, often linked to temporomandibular joint (TMJ) disorders, can signal a misalignment that places excessive strain on the joint and surrounding muscles. This discomfort may manifest as frequent headaches, facial tension, or clicking and popping sounds when opening the mouth.
Functional problems are perhaps the most compelling reason people seek evaluation. If chewing food feels difficult, or if you frequently bite your cheeks or tongue while eating, it suggests the upper and lower teeth are not meeting in a coordinated manner. Speech impediments, such as difficulty articulating certain sounds, can also be related to an improper jaw position. Excessive or uneven wear on the teeth indicates a long-term malocclusion, where some teeth bear disproportionate pressure during biting.
Other symptoms relate to air flow and sleep quality. Chronic mouth breathing, loud snoring, or the more serious condition of obstructive sleep apnea can stem from a lower jaw positioned too far back, which narrows the airway. Additionally, a noticeable imbalance in facial appearance, such as a receding chin (retrognathism) or a protruding lower jaw (prognathism), are outward signs of skeletal discrepancies that may require surgical correction. The inability to comfortably close the lips without strain is another physical sign that the jaws are not aligned.
Underlying Structural Issues Requiring Intervention
The need for surgery is fundamentally determined by the location of the problem: is it purely dental or is it skeletal? Jaw surgery is reserved for correcting skeletal malocclusions, which are discrepancies in the size, shape, or position of the jawbones themselves. These issues often result from genetic factors, developmental problems, or trauma. Braces alone cannot change the size of the jawbone or move it relative to the skull.
Skeletal issues are categorized using dental classifications that describe the relationship between the jaws. For example, a Class II malocclusion results from a lower jaw that is underdeveloped or positioned too far back. Conversely, a Class III malocclusion involves a lower jaw that is overgrown or positioned too far forward, leading to an underbite. When these skeletal discrepancies are moderate to severe in adults, surgical repositioning of the bones is the only way to achieve a proper bite.
Facial asymmetry, where one side of the face looks notably different from the other, is another structural issue addressed by orthognathic surgery. This can result from uneven growth or congenital defects like cleft palate. Correcting these foundational bone imbalances is necessary for functional reasons and to improve facial proportionality.
The Professional Diagnostic Pathway
Determining the precise need for jaw surgery is a multidisciplinary process requiring collaboration between an orthodontist and an oral and maxillofacial surgeon (OMS). The process typically begins with a referral identifying a skeletal component beyond the scope of traditional braces. The surgeon conducts a thorough physical examination and reviews the patient’s medical history and symptoms.
The definitive diagnosis hinges on specialized imaging and measurements. Panoramic X-rays provide a broad view of the jaw structure and joints. Cephalometric X-rays, taken from the side of the head, are precisely measured to analyze the angular and linear relationships between specific points on the skull and jaws. These measurements are compared to established norms to quantify the exact degree of skeletal discrepancy.
Advanced three-dimensional imaging, such as a Cone-Beam Computed Tomography (CBCT) scan, creates a detailed 3D rendering of the facial bones, allowing the surgical team to visualize the anatomy with millimeter precision. Dental molds or intraoral scans are also taken to create a physical or digital model of the teeth. This comprehensive data is used for virtual surgical planning, where the surgeon performs the procedure on the computer model first to determine the ideal final position of the jaws and create custom surgical guides.
When Non-Surgical Treatment is Sufficient
Not all bite or jaw issues necessitate surgery. If the misalignment is primarily dental, non-surgical treatment is usually sufficient. Traditional orthodontics, such as braces or clear aligners, can effectively move teeth to correct crowding, spacing, and mild overbites or underbites.
Minor issues with the temporomandibular joint (TMJ) that cause pain or clicking are frequently managed without an operation. Initial treatments for TMJ include physical therapy, the use of oral splints or night guards to stabilize the joint, and anti-inflammatory medication.
The threshold for surgery is crossed when the problem is structural and skeletal in nature, meaning the bone positions are severely mismatched. If a patient has a moderate to severe skeletal discrepancy, or if non-surgical methods have failed, then orthognathic surgery is likely the appropriate course. The key distinction remains whether the correction requires moving the teeth (dental) or repositioning the jawbones (skeletal).