An evaluation of lidocaine hydrocarbonate compared with lidocaine hydrochloride for inferior alveolar nerve block.

The purpose of this study was to measure the degree of anesthesia obtained with 2.2% lidocaine hydrocarbonate, 2.2% lidocaine hydrocarbonate with 1:100,000 epinephrine, and 2% lidocaine hydrochloride with 1:100,000 epinephrine for inferior alveolar nerve block. Using a repeated-measures design, 30 subjects randomly received an inferior alveolar injection of each solution over the course of three successive appointments. The first molar, first premolar, lateral incisor, and contralateral canine (control) were blindly tested with an Analytic Technology pulp tester at 3-min cycles for 60 min. Anesthetic success was defined as no subject response to the maximum output (80 reading) of the pulp tester within 16 min and maintenance of this reading for the remainder of the testing period. Although subjects felt numb subjectively, anesthetic success as defined here ranged from 3% to 10% for the plain lidocaine hydrocarbonate; for the lidocaine hydrocarbonate and lidocaine hydrochloride solutions with epinephrine, success ranged from 37% to 63%. We conclude that 2.2% lidocaine hydrocarbonate without vasoconstrictor is not as effective as the other two preparations for inferior alveolar nerve block. The 2.2% lidocaine hydrocarbonate with epinephrine and 2%.