A clinical trial of intraligamentary anesthesia.

The effectiveness of the periodontal ligament injection in providing anesthesia for routine extractions and the possible mechanisms of action of the periodontal ligament injection in producing dental anesthesia were investigated in a clinical trial. Periodontal ligament injections were administered under strong pressure with lidocaine on 14 teeth, with epinephrine on seven teeth, and with normal saline on another seven teeth. The anesthesia attained was evaluated by: response of the teeth to an electric pulp tester, gingival probing around the teeth, and the ability for teeth to be extracted without pain. The results demonstrated that periodontal ligament injections with lidocaine were effective in providing adequate anesthesia for the performance of dental extractions. Lidocaine periodontal ligament injections were statistically and clinically more effective in attaining anesthesia than were epinephrine or saline injections. Epinephrine periodontal ligament injections resulted in a slight but statistically significant increase in the stimulus necessary to produce a patient response, when the teeth were stimulated with an electric pulp-tester. Saline injections produced no change in response to the stimulus tested. It appears, based on the results of the saline and epinephrine injections, that hydrostatic pressure had no direct effect on the production of anesthesia with the periodontal ligament injection.