Damages of trigeminal nerve, particularly inferior alveolar nerve and lingual nerve, could occur following dental procedures. In some cases, nerve damage may happen as a complication of the local anesthetic injection itself and not of the surgical procedure.

From September 2006 to August 2010, 5 cases of inferior alveolar nerve and lingual nerve damages, which were assumed to happen solely due to local anesthesia, were reviewed. All cases were referred to Division of Oral and Maxillofacial Surgery, Department of Dentistry, Hanyang University Medical Center for legal authentication in the process of criminal procedure.

In all five cases, patients complained of altered sensation occurred in the distribution of the inferior alveolar or lingual nerve following block anesthesia. The local anesthetics were 2% lidocaine with 1 : 100,000 epinephrine and the amount of local anesthetics, which were used during injection, were varied. Most of patients experienced the electric stimulation during injection. Recovery was poor and professional supportive care was mostly absent.

Dental practitioners should consider that the surgical procedure caused the trigeminal nerve damage, however, dental local anesthesia for inferior alveolar nerve and lingual nerve could be one of the causes for damages. The various mechanisms for nerve damages by local anesthesia are thoroughly discussed.