Retrospective review of voluntary reports of nonsurgical paresthesia in dentistry.

OBJECTIVE Paresthesia is an adverse event that may be associated with the administration of local anesthetics in dentistry. The purpose of this retrospective study was to analyze cases of paresthesia associated with local anesthetic injection that were voluntarily reported to Ontario"s Professional Liability Program (PLP) from 1999 to 2008 inclusive, to see if the findings were consistent with those from 1973 to 1998 from this same source. MATERIALS AND METHODS All cases of nonsurgical paresthesia reported from 1999 to 2008 were reviewed; cases involving surgical procedures were excluded. Variables examined included patient age and gender, type and volume of local anesthetic, anatomic site of nerve injury, affected side and pain on injection or any other symptoms. RESULTS During the study period, 182 PLP reports of paresthesia following nonsurgical procedures were made; all but 2 were associated with mandibular block injection. There was no significant gender predilection, but the lingual nerve was affected more than twice as frequently as the inferior alveolar nerve. During 2006-2008 alone, 64 cases of nonsurgical paresthesia were reported to PLP, a reported incidence of 1 in 609,000 injections. For the 2 local anesthetic drugs available in dental cartridges as 4% solutions, i.e., articaine and prilocaine, the frequencies of reporting of paresthesia were significantly greater than expected (chi2, exact binomial distribution; p < 0.01) based on their level of use by Ontario dentists. These data suggest that local anesthetic neurotoxicity may be at least partly involved in the development of postinjection paresthesia.