The purpose of this study was to measure the degree of anesthesia following the administration of 3.6 ml of 2% lidocaine solutions with either 1:50,000, 1:80,000, or 1:100,000 for inferior alveolar nerve block and to compare the results with those obtained following the administration of 1.8 ml of the same solutions (1). With the use of a repeated measures design, 30 subjects randomly received an inferior alveolar injection at 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 50 min. The degree of anesthesia was comparable for the three solutions following the administration of 3.6 ml of each solution. Retrospective evaluation showed that the volume of the solution influenced the degree of anesthesia.