Impacted wisdom teeth can cause a variety of problems, including numbness in the jaw and the tongue. However, this is uncommon. Impacted lower (mandibular) wisdom teeth are often very close to a large nerve (inferior alveolar nerve) that controls feeling (sensation) to the lower jaw, teeth and tongue.
Treatment of impacted wisdom teeth typically involves their surgical removal (extraction). This procedure may cause temporary numbness in your jaws, tongue and teeth. However, numbness in the lower jaw and tongue before surgical removal of impacted wisdom teeth is unusual and may indicate a problem that requires further evaluation.
In some cases, impacted wisdom teeth can be associated with cysts and tumors — usually noncancerous. Other types of growths also can occur in the jaw area and result in the symptoms you describe.
Consult your dentist about the numbness you’re experiencing. A clinical and X-ray examination of your mouth, jaws and neck can help detect any potential problems. A panoramic X-ray is the gold standard for initial evaluation, but other imaging tests such as computerized tomography or magnetic resonance imaging also may be needed.
The source of this article is http://www.mayoclinic.com/health/impacted-wisdom-teeth/AN01549