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.