Occurrence of paresthesia after dental local anesthetic administration in the United States.

BACKGROUND: Several studies have suggested that the likelihood of paresthesia may depend on the local anesthetic used. The purpose of this study was to determine if the type of local anesthetic administered had any effect on reports of paresthesia in dentistry in the United States. METHODS: The authors obtained reports of paresthesia involving dental local anesthetics during the period from November 1997 through August 2008 from the U.S. Food and Drug Administration Adverse Event Reporting System. They used chi(2) analysis to compare expected frequencies, on the basis of U.S. local anesthetic sales data, with observed reports of oral paresthesia. RESULTS: During the study period, 248 cases of paresthesia occurring after dental procedures were reported. Most cases (94.5 percent) involved mandibular nerve block. The lingual nerve was affected in 89.0 percent of cases. Reports involving 4 percent prilocaine and 4 percent articaine were 7.3 and 3.6 times, respectively, greater than expected (chi(2), P < .0001) on the basis of local anesthetic use by U.S. dentists. CONCLUSIONS: These data suggest that paresthesia occurs more commonly after use of 4 percent local anesthetic formulations. These findings are consistent with those reported in a number of studies from other countries. CLINICAL IMPLICATIONS: Until further research indicates otherwise, dentists should consider these results when assessing the risks and benefits of using 4 percent local anesthetics for mandibular block anesthesia.

Survey of local anesthetic use by Ontario dentists.

OBJECTIVE: Local anesthetics are believed to be the most frequently used drugs in clinical dentistry, and although they are generally regarded as safe, some adverse reactions can be expected and do occur. The purpose of this study was to obtain, by means of a mail survey, information on the types and amounts of local anesthetics used by Ontario dentists during 2007. MATERIALS AND METHODS: A survey requesting data on the annual use of injectable local anesthetics was mailed to all 8,058 dentists licensed by the Royal College of Dental Surgeons of Ontario in 2007. RESULTS: The effective response rate to the single mailing was 17.3% (1,395 respondents). By extrapolation, the estimated use of local anesthetics by all Ontario dentists during 2007 was determined to be about 13 million cartridges, which represents an average of 1,613 cartridges per dentist per year. Lidocaine with epinephrine 1:100,000 was the most commonly used formulation with 37.31% of total anesthetic use, followed by articaine with 1:200,000 epinephrine (27.04%) and articaine with 1:100,000 epinephrine (17.16%). Overall, local anesthetics combined with a vasoconstrictor accounted for more than 90% of total anesthetic use. A minority of survey respondents (15.68%) indicated that their pattern of anesthetic use had changed significantly in the past few years. Patterns of use were similar for early and late survey respondents. These data provide a current account of the use of local anesthetics by Ontario dentists.

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.