Does the combination of 3% mepivacaine plain plus 2% lidocaine with epinephrine improve anesthesia and reduce the pain of anesthetic injection for the inferior alveolar nerve block? A prospective, randomized, double-blind study.

INTRODUCTION: In theory, using 3% mepivacaine initially for an inferior alveolar nerve (IAN) block would decrease the pain of injection, provide faster onset, and increase anesthetic success. The purpose of this prospective, randomized, double-blind study was to compare the degree of pulpal anesthesia obtained with a combination of 3% mepivacaine/2% lidocaine (1:100,000 epinephrine) versus a combination of 2% lidocaine (1:100,000 epinephrine)/2% lidocaine (1:100,000 epinephrine) in IAN blocks. Injection pain was also studied.

METHODS: One hundred asymptomatic subjects were randomly given a combination of a 1-cartridge volume of 3% mepivacaine plus a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine and a combination of a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine plus a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine for the IAN block at 2 separate appointments. Subjects rated the pain of injection. The molars, premolars, and incisors were tested with an electric pulp tester in 4-minute cycles for 60 minutes. Anesthetic success was defined as the subject achieving 2 consecutive 80 readings within 15 minutes after completion of the IAN blocks and sustaining the 80 reading for 60 minutes.

RESULTS: Success was not significantly different (P > .05) between the 2 combinations. No statistical differences in injection pain or onset times were found.

CONCLUSIONS: The combination of 3% mepivacaine plus 2% lidocaine with 1:100,000 epinephrine was equivalent to the combination of 2 cartridges of 2% lidocaine with 1:100,000 epinephrine in terms of injection pain, onset time, and pulpal anesthetic success for the IAN block.