Orthognathic surgery, commonly known as jaw surgery, is a specialized procedure that corrects irregularities in the jaw bones to improve alignment and function. This intervention is considered when a person’s upper jaw (maxilla), lower jaw (mandible), or both are misaligned, creating a skeletal problem that cannot be resolved through orthodontics alone. The goal of this surgery is to reposition the jawbones to achieve a balanced bite and a more harmonious facial structure. Understanding the difference between simple dental issues and structural problems is the first step toward determining if this complex treatment is necessary.
Recognizing Symptoms That Indicate a Skeletal Problem
Symptoms suggesting a misalignment rooted in the jawbone structure are often chronic and interfere significantly with a person’s daily life. One of the most common signs is severe difficulty chewing, biting, or swallowing food effectively, which can lead to inefficient digestion and nutritional challenges. This functional impairment occurs because the teeth cannot meet properly to shear or grind food due to the underlying skeletal discrepancy.
Speech difficulties, such as a lisp or other pronunciation issues, may also point toward a jaw alignment problem, as the tongue’s movement is constrained by the position of the jaws and teeth. Chronic jaw pain or temporomandibular joint (TMJ) discomfort that remains unresponsive to conservative treatments like splints or physical therapy suggests a structural load on the joint.
A noticeable lack of facial symmetry, where one side of the jawline or chin appears uneven compared to the other, often indicates uneven growth of the jawbones. Furthermore, an inability to comfortably close the lips without strain, often resulting in persistent mouth breathing, signals a skeletal mismatch between the upper and lower jaws.
Conditions Jaw Surgery Corrects
Orthognathic surgery is necessary to correct specific structural diagnoses that involve a mismatch between the size or position of the upper and lower jawbones. The procedure is indicated for severe malocclusions, which are bite discrepancies too large to be corrected by moving the teeth alone. This includes Class II or Class III bite discrepancies, where the upper or lower jaw is significantly over- or underdeveloped relative to the other.
A common diagnosis is mandibular retrognathism, characterized by an underdeveloped lower jaw that sits too far back, or conversely, mandibular prognathism, where the lower jaw is overdeveloped and protrudes forward. The surgery also addresses open bite, a condition where the front teeth do not overlap vertically when the back teeth are closed, leaving a gap. Moreover, skeletal issues that contribute to Obstructive Sleep Apnea (OSA) often require jaw advancement surgery to physically widen the airway behind the tongue and soft palate. These conditions represent structural boundaries that traditional orthodontics cannot overcome.
Non-Surgical Treatments Before Considering Surgery
In most cases, less invasive treatments are explored first to determine if the problem is purely dental or can be managed without altering the jawbone structure. Traditional orthodontics, using braces or clear aligners, aims to move teeth within the existing bone structure to improve alignment and bite. These methods are highly effective for correcting crowding, spacing, and mild bite issues where the skeletal foundation is mostly sound.
Conservative management techniques are also employed for temporomandibular joint issues, including custom-fitted splints or mouthguards to stabilize the bite and reduce joint strain. Physical therapy and anti-inflammatory medication can help manage muscle pain and improve jaw mobility. However, when the discrepancy between the upper and lower jawbones exceeds approximately 5 to 10 millimeters, these non-surgical options are insufficient. They cannot physically change the length or position of the jawbones, and the dental camouflage achieved by orthodontics in these cases is often unstable.
The Professional Diagnostic Process
The decision to proceed with jaw surgery requires a joint treatment plan developed by an orthodontist and an oral and maxillofacial surgeon (OMS). The process begins with a thorough clinical examination and the collection of detailed records, ensuring that both the dental alignment and the underlying skeletal position are considered.
Diagnostic imaging is a crucial step in confirming the skeletal nature of the problem and involves specialized X-rays. A panoramic X-ray provides a full view of the teeth and surrounding bone, while a cephalometric X-ray, taken from the side, precisely measures the relationship between the skull, jaws, and teeth. Increasingly, a three-dimensional Cone Beam Computed Tomography (CBCT) scan is used to create a highly accurate 3D model of the facial skeleton and airway.
The orthodontist also creates dental study models (physical or digital molds of the teeth) to analyze the bite in minute detail. Using the imaging data, the surgical team engages in virtual surgical planning, where the jaw movements are simulated on the 3D model with sub-millimeter accuracy.