Orthodontic treatment uses carefully controlled mechanical forces to realign teeth and jaws. While routine treatment is overwhelmingly safe, the close proximity of teeth to major sensory pathways introduces a theoretical, though extremely rare, risk of nerve irritation or injury. Orthodontists are extensively trained to apply forces that respect the biological limits of the body and use advanced diagnostic imaging to mitigate these risks. Understanding the anatomy of the jaw and the precise nature of these potential interactions underscores the importance of professional oversight throughout treatment.
Nerves and Structures Affected by Orthodontic Treatment
The primary sensory nerves involved in lower jaw orthodontic procedures originate from the trigeminal nerve, which is responsible for sensation in the face. The inferior alveolar nerve (IAN) is a major branch that travels through the mandibular canal inside the lower jawbone. This nerve provides sensation to all lower teeth and the surrounding bone.
The IAN gives rise to the mental nerve, which exits the jawbone through the mental foramen, typically located near the roots of the lower premolars. The mental nerve provides sensation to the skin of the chin and the lower lip.
The lingual nerve is another significant branch, running outside the bone near the inner surface of the jawbone, particularly in the molar region. Unlike the IAN, which is protected within the bony canal, the lingual nerve is situated in the soft tissues of the floor of the mouth.
The close anatomical relationship between these nerves and the tooth roots means any procedure involving tooth movement requires careful planning. Orthodontic forces move the roots through the bone, often coming near these critical nerve pathways.
How Orthodontic Forces Interact with Nerves
The forces used to move teeth can affect the nerves in two primary ways: internally, by influencing the nerve within the tooth itself, and externally, by causing root proximity to a major nerve canal. The pressure necessary for tooth movement temporarily reduces blood flow to the dental pulp, the soft tissue containing the tooth’s nerve and blood vessels.
This effect causes mild, transient inflammation known as reversible pulpitis. Reversible pulpitis is an expected, temporary side effect resulting in tooth sensitivity that resolves once blood flow stabilizes. In extremely rare instances, particularly in teeth with a history of trauma, the force may lead to irreversible pulp damage requiring a root canal procedure.
External nerve irritation can occur if a tooth root is moved into very close proximity to the mandibular canal containing the inferior alveolar nerve. This is most commonly a concern when moving lower molars or premolars whose roots are naturally near the canal.
Cases of nerve symptoms that arise solely from routine tooth movement are exceedingly rare. When they do occur, symptoms are generally temporary and resolve within a few weeks after the orthodontic force is removed.
Trauma from Ancillary Orthodontic Procedures
The most significant risk for nerve damage comes not from the braces themselves, but from procedures performed alongside them. The placement of Temporary Anchorage Devices (TADs), which are small titanium mini-screws, requires careful planning to avoid nerve structures. A TAD placed too close to the inferior alveolar nerve canal or the mental nerve can cause direct mechanical trauma.
Pre-operative imaging, such as Cone-Beam Computed Tomography (CBCT), is used to precisely map the location of the nerve canal to prevent this complication. Studies show that if a dental implant or mini-screw is placed within one millimeter of the IAN canal, the incidence of neurosensory changes rises significantly, highlighting the need for absolute precision.
Similarly, surgical procedures performed before or during orthodontic treatment, such as wisdom tooth extraction or orthognathic (jaw) surgery, carry a higher risk of nerve injury. Mandibular orthognathic surgery, like the Bilateral Sagittal Split Osteotomy (BSSO), involves cutting and repositioning the jawbone.
This places the inferior alveolar nerve at direct risk of stretching or compression. While a high percentage of patients experience temporary sensory changes after this major surgery, the risk of permanent sensory alteration is still present. These surgical risks are managed by highly experienced oral and maxillofacial surgeons.
Identifying and Treating Nerve-Related Symptoms
Nerve irritation or injury manifests as an altered sensation in the area supplied by the affected nerve, usually the lower lip, chin, or tongue. The most common symptoms are paresthesia, described as a tingling, prickling, or burning sensation, and anesthesia, which is a complete loss of feeling. A less common but more unpleasant symptom is dysesthesia, which involves painful, altered sensations.
Patients must report any persistent or sudden changes in sensation to their orthodontist immediately, as timely intervention can significantly improve the outcome. If symptoms are believed to be caused by routine tooth movement, removing the orthodontic force or modifying the appliance usually allows the nerve to recover.
For transient nerve irritations, symptoms often resolve quickly, with a median recovery time of approximately 17 days in force-related cases. If symptoms persist beyond six to eight weeks, a referral to a specialist, such as an oral surgeon or neurologist, is warranted for a formal neurosensory examination.
The specialist will monitor the nerve recovery over several months, often prescribing medications to support nerve healing. While full recovery can take six to twelve months, the vast majority of nerve injuries sustained during dental procedures are temporary; symptoms lasting beyond this period, which are classified as permanent, are rare.