Braces are specialized appliances used to straighten teeth and correct the bite, a process that relies on controlled biological responses within the mouth. Patients often worry about the potential for structural changes, particularly the unwanted sideways movement of the jaw itself. Orthodontic treatment is a precise science, and understanding the mechanics behind it clarifies the difference between intended tooth movement and major jaw alteration. This knowledge provides reassurance about the limits and capabilities of standard braces and the deliberate steps required for any skeletal change.
The Difference Between Dental and Skeletal Movement
Standard braces are designed to move the teeth, not the bones of the jaw. The dentition, which includes the teeth and their supporting sockets, is the primary target of orthodontic force. Teeth are not rigidly fixed into the jawbone but are suspended within the alveolar bone sockets by a network of fibers called the periodontal ligament.
The gentle, continuous pressure applied by brackets and wires stimulates a biological process known as bone remodeling. On the side of the tooth where pressure is applied, specialized cells called osteoclasts break down the bone tissue. Simultaneously, on the opposite side where the ligament is under tension, cells called osteoblasts build new bone to stabilize the tooth in its new position. This process allows the tooth to migrate slowly, typically about 1 millimeter every four to six weeks. This localized force is precisely calibrated to affect only the alveolar bone that immediately surrounds the tooth root. The dense, larger skeletal structures of the upper jaw (maxilla) and the lower jaw (mandible) are significantly more resistant to this type of gentle force. Standard orthodontic forces are simply too light and too focused on the dental arch to cause the entire jawbone to shift laterally.
Addressing Unintentional Lateral Jaw Shift
Standard fixed braces cannot accidentally cause the entire lower jaw to shift permanently to one side, a condition known as mandibular deviation. The forces applied are strictly used to realign the teeth within their existing skeletal framework. If a patient experiences a feeling that their jaw is suddenly misaligned or shifting, it is typically a temporary consequence of the changing bite, not a structural bone movement. As teeth move, the way the upper and lower teeth meet (the occlusion) changes, which forces the lower jaw to find a new path of closure. This repositioning of the mandible to accommodate the changing bite can create a temporary, perceived lateral shift as the jaw muscles adjust.
Furthermore, if a patient has a pre-existing skeletal asymmetry, the straightening of the teeth may unmask this underlying condition, making the deviation more noticeable. If a lateral correction is necessary to address a crossbite or a skeletal asymmetry, it is an intentional, planned movement requiring specific orthopedic tools, not a side effect of routine tooth movement. A planned transverse expansion of the upper jaw, for instance, uses a different, stronger appliance to physically widen the arch, which can allow the lower jaw to center itself more naturally upon closing. The goal is to correct the alignment of the dental arches so the jaw can settle into a balanced position.
Symptoms Mistaken for Jaw Deviation
Many physical sensations that arise during orthodontic treatment are often misinterpreted as the jaw moving sideways. The most common is discomfort or symptoms related to the temporomandibular joint, or TMJ, which connects the lower jaw to the skull. As the bite changes, the jaw muscles and the joint must adapt to the new way the teeth interlock. This temporary adjustment can lead to muscle soreness, clicking, popping sounds, or a feeling of tension near the ears. These symptoms often create the illusion that the jaw is out of alignment, though the primary cause is the muscle and joint strain from the changing occlusion.
Once the teeth have settled into a stable, final bite, these symptoms typically resolve as the muscles relax and adapt to the corrected position. Another temporary sensation is the feeling of dental asymmetry caused by the teeth moving at different rates. If one side of the dental arch is being corrected more quickly than the other, the resulting unevenness can make the patient feel like their entire jaw is shifting. This feeling is a result of the intermediate, unstable bite position and is a normal part of the process before the final alignment is achieved.
Intentional Jaw Realignment in Orthodontics
While standard braces only move teeth, the jaw structure itself can be intentionally repositioned under specific circumstances. For growing patients, orthopedic devices known as functional appliances may be used to modify the development of the jaw bones. Appliances such as the Herbst or MARA are designed to hold the mandible in a corrected position, encouraging favorable growth and structural change over time. For adult patients whose jaw growth is complete, skeletal correction requires a much more significant intervention. Orthognathic surgery, or corrective jaw surgery, is the procedure used to address severe skeletal discrepancies, such as a substantial underbite, overbite, or lateral jaw deviation.
During this surgery, the jawbones are physically cut and repositioned into a more balanced and functional alignment, then secured with small titanium plates and screws. This surgical approach is a complex, planned procedure performed by an oral and maxillofacial surgeon in collaboration with the orthodontist. The need for orthognathic surgery is determined through extensive analysis and planning, confirming that any structural jaw change is a deliberate, major undertaking distinct from routine tooth straightening with braces.