Effectiveness of 20% benzocaine as a topical anesthetic for intraoral injections.

The use of topical anesthetics has been advocated prior to the administration of various types of anesthetic injections. Reported results have varied between studies. The purpose of this study was to compare the effectiveness of 20% benzocaine in reducing the pain of needle insertion during maxillary posterior and anterior infiltration and inferior alveolar nerve block injections. In this retrospective study, 1080 patients received 2336 injections using a 27-gauge needle. Topical anesthetic was applied prior to 720 of the injections. Patients rated pain of needle insertion using a 0-4 pain scale. Logistic regression analysis showed no differences in pain ratings between topical and no topical groups for the inferior alveolar nerve block and posterior maxillary infiltration injections. The use of topical anesthetic did reduce the pain of needle insertion with the maxillary anterior injections (P = .0041).