Wisdom teeth, or third molars, typically emerge between the ages of 17 and 25. Because the jaw often lacks sufficient space, these teeth frequently become impacted, meaning they are trapped beneath the gum line or bone. While wisdom tooth removal is a common procedure, it carries a small, well-documented risk of causing nerve damage. This sensory disturbance can occur either due to the pressure from the impacted tooth itself or, more commonly, as a complication during the surgical extraction process.
How Wisdom Teeth Cause Nerve Trauma
Nerve trauma can happen in two distinct ways: before the procedure due to the tooth’s position, or during the surgical removal itself. An impacted wisdom tooth, especially one angled horizontally, can lie directly against or be extremely close to the major nerve pathways that run through the jawbone. This proximity can lead to chronic irritation or compression of the nerve, which may result in altered sensation even before any surgery takes place.
The most frequent cause of nerve damage is the surgical extraction of the tooth. The Inferior Alveolar Nerve travels within the mandibular canal, a bony tunnel that runs through the lower jawbone, positioned directly underneath the roots of the lower wisdom teeth. When the roots of the tooth are deeply embedded or wrap around this canal, the manipulation necessary to remove the tooth can bruise, stretch, or compress the nerve. Pre-operative imaging, such as a cone-beam computed tomography (CBCT) scan, is often used to assess the exact distance between the tooth roots and the nerve canal, which is the primary factor determining surgical risk.
The Nerves Affected and Resulting Symptoms
Two specific nerves are most commonly at risk during the removal of lower wisdom teeth: the Inferior Alveolar Nerve (IAN) and the Lingual Nerve (LN).
The IAN is a sensory nerve that travels through the jawbone and provides sensation to the lower teeth, the lower lip, the chin, and the associated gums. Damage to the IAN typically results in sensory changes in the lower lip and chin on the side of the extraction.
The Lingual Nerve is located much closer to the surface, running along the inner side of the lower jaw, near the tongue. This nerve is responsible for general sensation and taste perception on the front two-thirds of the tongue. Due to its location and delicate nature, the LN is vulnerable to trauma from surgical tools or the flap of tissue needed to expose the wisdom tooth.
When a nerve is damaged, the resulting symptoms are collectively known as sensory disturbances. Paresthesia is the most common symptom, characterized by a persistent feeling of numbness or a “pins-and-needles” tingling sensation in the affected area. Dysesthesia is a more severe sensory alteration where the patient experiences an unpleasant, painful, or abnormal sensation, such as burning or electric shock-like pain.
Recovery and Long-Term Outcomes
The prognosis for nerve injury following wisdom tooth surgery is generally favorable, as most cases involve temporary damage. Temporary nerve injuries, often classified as neuropraxia (nerve bruising or stretching), resolve as the nerve sheath heals and the swelling around the nerve decreases. Temporary sensory changes, such as mild numbness or tingling, occur in an estimated 0.5% to 5% of all lower wisdom tooth extractions.
For the majority of patients who experience nerve trauma, sensation begins to return within days or weeks as the nerve regenerates or recovers from the trauma. Full recovery for these temporary injuries typically occurs within six months.
However, in less than 1% of cases, the nerve injury is more severe and results in long-lasting or permanent sensory deficits. If symptoms persist for several months without significant improvement, the damage may be categorized as axonotmesis or neurotmesis, indicating a serious injury that affects the nerve fibers or involves a complete severance. Persistent cases require specialist intervention, which may include medical management with nerve-specific medications, or, in rare instances, microsurgery to repair or graft the damaged nerve segment. Early evaluation and monitoring by a specialist are necessary to determine the severity of the injury and guide the most effective management strategy.