Retrospective Review of Dental Local Anesthetic Induced Paresthesia in UK

Background: Local anesthetics are essential drugs in dentistry.  Unfortunately, as with other drugs, there are risks associated with their use, such as paresthesia.  

Objective: To examine whether there is a difference in the incidence of paresthesia among the currently available local anesthetics used for dentistry in the UK. 

Method: This study is based in part on data obtained under licence from the UK Medicines and Healthcare Products Regulatory Agency. The interpretations and conclusions are the authors’ alone. The source of data was voluntary reports of paresthesia from local anesthetic use between 1998 and 2008 inclusive, found in their Sentinel Pharmacovigilance Database. The Yellow Card reports were examined and only cases pertaining to dental use were included.   Patient age and gender, type of local anesthetic, and the site of nerve injury, was noted. Statistical significance was tested using the Chi-Square analysis which compared expected frequencies of paresthesia based on the UK dental anesthetic sales data, obtained from Strategic Data Marketing, to the observed reports paresthesia. 

Result: During the study period, 44 cases of paresthesia met the inclusion criteria.  61% of affected patients were female with a mean age of 41.9 years. 85% of the cases involved the mandible and the lingual nerve was most often affected. The overall incidence of reported paresthesia was 1 in 9,698,358 injections. The frequency of observed paresthesia associated with articaine, which is the most widely used 4% solution in the UK., was 5.9 times greater than expected (χ², p<0.0001).

Conclusion: These data suggest that paresthesia after the injection of local anesthetic in dentistry is rare, yet more likely to occur if a 4% solution is used.