Anesthetic Success Using Nitrous Oxide and a Combination of Lidocaine/Clonidine for the Inferior Alveolar Nerve Block and the Effects on Blood Pressure and Pulse in Patients with Symptomatic Irreversible Pulpitis: A Prospective, Randomized, Double-blind Study.

Introduction: The pulpal anesthetic success rates for an inferior alveolar nerve block (IANB) alone in patients presenting with symptomatic irreversible pulpitis are less than adequate. Nitrous oxide and clonidine have shown increases in IANB success when administered individually, but their success has not been evaluated when used together. The purpose of this prospective, randomized, double-blind study was to determine the effect of nitrous oxide/oxygen plus an IANB using lidocaine/clonidine on the success of the IANB in patients with symptomatic irreversible pulpitis and to evaluate the effect of clonidine on blood pressure and pulse.
Methods: Sixty-two emergency patients experiencing moderate to severe pain and a diagnosis of symptomatic irreversible pulpitis were enrolled. Subjects were randomly divided into 2 groups and received nitrous oxide/oxygen and an IANB using 2% lidocaine with either 27 μg clonidine or 18 μg epinephrine as vasoconstrictors. Blood pressure and pulse were recorded before and during the emergency endodontic treatment. Anesthetic success was defined as no or mild pain upon access and instrumentation of the canals.
Results: The pulpal anesthetic success rate in both treatments was 58%, with no significant difference between the groups. There was no statistically significant difference in pulse or systolic blood pressure with the use of clonidine compared with epinephrine. Diastolic blood pressure was significant.
Conclusions: The use of nitrous/oxide plus the addition of lidocaine/clonidine for the IANB in teeth with symptomatic irreversible pulpitis resulted in no statistically significant difference in anesthetic success of the IANB. There were no statistically significant differences in pulse or systolic blood pressure with the use of clonidine compared with epinephrine; diastolic blood pressure was significant.
(Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)