Pain and temperature sensations related to local analgesia

Following the injection of local analgesic solutions at room temperature (21 degrees C) and at normal body temperature (37 degrees C), respectively, in the oral submucosal region, it was found that most of the subjects experienced the solutions as being of body temperature, regardless of whether the temperature of the solution was 37 degrees C or 21 degrees C. The duration of soft tissue anesthesia was not influenced by the temperature of the solutions. After the anesthetic effect had subsided, prilocaine 4% caused post-analgesic pain less frequently than did lidocaine 2% with adrenalin 12.5 mug/ml. Following injections with different mepivacaine solutions it was found that a low pH caused more frequent pain than a high pH, that the addition of a vasoconstrictor caused more frequent pain than a plain solution, and that there was a tendency for more frequent pain with increasing concentrations of the local anesthetic agent. In this study the addition of adrenalin was not found to prolong the period of soft tissue anesthesia.