Effect of Sodium Bicarbonate Buccal Infiltration on the Success of Inferior Alveolar Nerve Block in Mandibular First Molars with Symptomatic Irreversible Pulpitis: A Prospective, Randomized Double-blind Study.

INTRODUCTION The purpose of this prospective, randomized, double-blind study was to evaluate the effect of a buccal infiltration of sodium bicarbonate on the anesthetic success of the inferior alveolar nerve block (IANB) for mandibular first molars in patients with symptomatic irreversible pulpitis. METHODS One hundred patients diagnosed with symptomatic irreversible pulpitis of a mandibular first molar were selected. The patients randomly received a buccal infiltration injection of either 0.7 mL 8.4% sodium bicarbonate with 0.3 mL 2% lidocaine containing 1:80,000 epinephrine or 0.7 mL sterile distilled water with 0.3 mL 2% lidocaine containing 1:80,000 epinephrine in a double-blind manner. After 15 minutes, all the patients received conventional IANB injection using 3.6 mL 2% lidocaine with 1:80,000 epinephrine. Access cavity preparation was initiated 15 minutes after the IANB injection. Lip numbness was a requisite for all the patients. Success was determined as no or mild pain on the basis of Heft-Parker visual analog scale recordings upon access cavity preparation or initial instrumentation. Data were analyzed using the t, chi-square and Mann-Whitney U tests. RESULTS The success rate after the buccal infiltration of sodium bicarbonate was 78%, whereas without the buccal infiltration of sodium bicarbonate it was 44% (P < .001). CONCLUSIONS A buccal infiltration of 0.7 mL 8.4% sodium bicarbonate increased the success rate of IANBs in mandibular first molars with symptomatic irreversible pulpitis.