Efficacy of Articaine Versus Lidocaine Administered as Supplementary Intraligamentary Injection after a Failed Inferior Alveolar Nerve Block: A Randomized Double-blind Study.

INTRODUCTION: The present study comparatively evaluated the anesthetic efficacy of 4% articaine versus 2% lidocaine given as supplemental intraligamentary injections after a failed inferior alveolar nerve block. METHODS: One hundred six adult patients with symptomatic irreversible pulpitis in a mandibular first or second molar received an initial inferior alveolar nerve block with 2% lidocaine with 1:80,000 epinephrine. Pain during the endodontic treatment was assessed using the Heft-Parker visual analog scale. Eighty-two patients with unsuccessful anesthesia were randomly allocated to 2 treatment groups: 1 group received 0.6 mL/root of supplementary intraligamentary injection of 4% articaine with 1:100,000 epinephrine, and the second group received 2% lidocaine with 1:80,000 epinephrine. Endodontic treatment was reinitiated. Success after the primary injection or supplementary injection was defined as no or mild pain (less than 55 mm on the Heft-Parker visual analog scale) during access preparation and root canal instrumentation. Patients' heart rate was monitored using a finger pulse oximeter. The anesthetic success rates were analyzed with the Pearson chi-square test at 5% significance levels. The heart rate changes were analyzed using the t test. RESULTS: The patients receiving supplementary intraligamentary injections of 4% articaine had a success rate of 66%, whereas 2% lidocaine injections were successful in 78% of cases. The difference was statistically nonsignificant (chi(2) = 1.51, P = .2). There was no significant effect of the different anesthetic agents on the heart rate. CONCLUSIONS: Both 4% articaine and 2% lidocaine improved the success rates after a failed primary anesthetic injection, with no significant difference between them.