The lingual nerve, a branch of the trigeminal nerve, provides general sensation (touch, pain, temperature) to the front two-thirds of the tongue, floor of the mouth, and lingual gum tissue. It also carries taste signals from this area via facial nerve fibers. This nerve enables functions like speaking, chewing, and taste perception. When injured, lingual nerve damage disrupts these abilities.
Causes of Lingual Nerve Damage
Lingual nerve injuries most often stem from medical procedures, particularly those involving the mouth and jaw. Dental procedures, especially third molar (wisdom tooth) extractions, are the most common cause of injury. The lingual nerve runs very close to the lower wisdom teeth, making it vulnerable to stretching, compression, or direct laceration during extraction. Temporary injury occurs in about 2% of cases, with permanent damage seen in approximately 0.2% of extractions.
Other dental interventions can also affect the lingual nerve. These include local anesthetic injections, particularly inferior alveolar nerve blocks. Dental implants, root canal treatments, and removal of lower jaw cysts or tumors are also potential causes. Beyond dental work, other sources of injury include trauma to the face or jaw, such as fractures or lacerations to the floor of the mouth. Complications arising from general anesthesia intubation or salivary gland surgeries can also impact the nerve due to its anatomical proximity.
Recognizing the Symptoms
Lingual nerve damage can manifest through sensory and functional difficulties on the affected side of the tongue. People often report numbness, a complete loss of sensation, or altered sensations such as tingling or a “pins and needles” feeling, medically termed paresthesia. Some individuals experience painful or unpleasant sensations, like burning or electric shock-like pain, known as dysesthesia.
The ability to taste can also be affected, leading to diminished or lost taste on the front portion of the tongue. This altered taste, or dysgeusia, might present as a metallic or unusual flavor.
These sensory disturbances can lead to practical challenges. Speech difficulties, such as slurring or a lisp, may occur due to impaired tongue function. Chewing food can become problematic, increasing the risk of biting the tongue. Drooling or difficulty keeping food and liquids in the mouth can also occur, impacting eating and drinking.
Prognosis and Natural Recovery
Recovery from lingual nerve damage varies significantly depending on the injury’s extent and nature. Minor injuries, where the nerve is bruised or stretched without being severed, generally have a better outlook for spontaneous healing. These less severe forms of damage, sometimes referred to as neuropraxia, often see a full recovery.
A considerable number of lingual nerve injuries resolve on their own over time. Approximately 90% of these injuries are temporary, with most improvement occurring within eight to twelve weeks. If symptoms persist beyond three months, it suggests a more involved injury to the nerve. If altered sensations or functional difficulties continue for longer than six months, the damage is generally considered permanent. Nerve regeneration is a slow process, typically progressing at a rate of about 1 millimeter per week.
Treatment and Management Options
Initial management of lingual nerve damage often involves observation, especially for milder injuries, to allow for natural healing. This “wait and see” approach is common, as many temporary injuries improve on their own within the first few months after the incident. If spontaneous recovery does not occur or is incomplete, further interventions may be considered.
Medical management can include prescription medications for neuropathic pain. Antidepressants or anticonvulsants are sometimes prescribed for burning or electric shock-like sensations. Nerve blocks may also reduce localized pain.
For more severe injuries or those showing no improvement, surgical intervention becomes an option. Surgery aims to repair the damaged nerve, involving scar tissue removal, direct rejoining of nerve ends, or nerve grafts for larger defects. Surgical repair is typically considered within three to six months, with earlier intervention often yielding better outcomes. Improvements can still be seen up to one year post-injury.