Glossary

Neurapraxia is the name given to a mild nerve injury that has been caused by either compression or retraction. In neurapraxia, there is no violation of the nerve trunk and no axonal degeneration and spontaneous recovery of the motor and/or sensory functions most often occurs within one to four weeks from the time of injury. Neurapraxia in dentistry is commonly caused by an injury to the inferior alveolar nerve or to the lingual nerve and may occur due to several possibilities including third molar extractions, anesthetic injections, oral disease, and surgical, orthodontic, and endodontic treatments or procedures. Neurapraxia symptoms include numbness, loss of sensation, motor paralysis, and tingling. Though neurapraxia typically does not require any specific treatment, patients should report their symptoms to their practitioner for monitoring and follow-up. In some cases, additional imaging may be needed to ensure there is not another underlying cause for the neurapraxia that must be addressed to promote healing.

Neurotmesis is a nerve injury involving a complete severance of the nerve trunk leading to Wallerian degeneration. Due to the severing of the nerve trunk, sensory and/or motor functions are impaired with the potential for recovery being very small. In implant dentistry, neurotmesis may be caused by an accidental incision of the nerve or any of the factors leading to axonotmesis. Neurotmesis may be caused in several different ways during a surgical procedure. First, the needle used in the injection of numbing medications prior to the surgery can nick, damage, or lacerate the nerve trunk. In addition, the medication itself may cause chemical damage if it is injected directly into the nerve. During the surgery itself, the nerve and/or nerve trunk may also be damaged due to excess movement or manipulation or through compression. A direct surgical mistake which leads to the severe laceration or severing of the nerve trunk can also be the cause of neurotmesis.