A clinical evaluation of the electric pulp tester as an indicator of local anesthesia

Local anesthesia is the primary method in dentistry to control patients' pain. However, several studies have shown that profound anesthesia is not always achieved. The electric pulp tester has been used to measure the level of local dental anesthesia during endodontic therapy. However, no study has been performed that evaluates the ability of the electric pulp tester to predict the efficacy of local anesthesia prior to as operative procedure. If ineffective anesthesia could be predicted, supplemental injections could be administered to alleviate the anesthetic problem. The purpose of this study was to evaluate the ability of the electric pulp tester to measure the level of local anesthesia prior to operative treatment. The study was performed in vivo on patients requiring operative therapy. All teeth were pulp tested preoperatively for vitality using the electric pulp tester. After injection of local anesthetic, traditional parameters of dental anesthesia were verified (lip numbness, mucosal sticks). Teeth were then retested with the electric pulp tester and the results recorded. The teeth were them prepared for restoration using conventional instrumentation, and the patient's level of anesthesia evaluated using a visual analog scale. The electric pulp tester readings were compared to the patient's responses using Fisher's Exact test (two-tail). The results indicate that the electric pulp tester can be a valuable tool in predicting potential anesthetic problems in operative (restorative) dentistry.