In the first study, a topical anesthetic patch or a placebo will be placed on the gum tissues next to four or five lower posterior teeth. The patch will removed at either 5, 10, or 15 minutes. An electronic test that sends a light electronic impulse into the tooth, lip sensitivity testing ("Is your lip numb?"), and discomfort reports will be started immediately after removal of the patch and repeated every 5 minutes for 30 minutes. An oral surgeon will then remove the patient's wisdom teeth (tooth).