Reversal of pulpal and soft tissue anesthesia by using phentolamine: a prospective randomized, single-blind study.

INTRODUCTION Phentolamine mesylate has been reported to be an effective local anesthetic reversal agent for soft tissue but has not been studied regarding reversal of pulpal anesthesia. The authors conducted a prospective randomized, single-blind study comparing the reversal of pulpal and soft tissue anesthesia when phentolamine was administered at 30 minutes versus 60 minutes after the administration of an inferior alveolar nerve (IAN) block. METHODS Ninety adult subjects received 2 sets of injections consisting of an IAN block followed by an injection of phentolamine at 30 minutes and a sham injection at 60 minutes or a sham injection given at 30 minutes and a phentolamine injection given at 60 minutes in 2 separate appointments. The authors used an electric pulp tester to test the first and second molars, premolars, and incisors for pulpal anesthesia in 4-minute cycles for 120 minutes. Lip and tongue soft tissue anesthesia was also monitored. RESULTS Phentolamine significantly (P < .05) reduced duration of both pulpal and soft tissue anesthesia when administered at either 30 or 60 minutes after an IAN block. CONCLUSIONS Phentolamine would be beneficial for patients who would like to experience a faster return to normal soft tissue function and sensation after the administration of local anesthesia. However, because pulpal anesthesia is also reversed fairly rapidly, phentolamine should be administered at the end of the dental appointment.