Analgesic agents and strategies in the dental pain model.

Pain following removal of impacted third molar teeth has proven to be a useful clinical model for evaluating oral analgesics. Moreover, as the underlying pathophysiology becomes elucidated the model serves as a tool for monitoring the relative contributions of different pain events, including peripheral and central sensitization. Non-steroidal anti-inflammatory drugs (NSAIDs) demonstrate high potency in this model, reflecting the large contribution that peripheral prostaglandins may make to the pathophysiology of postoperative pain. However, other analgesic agents, with weak activity against peripheral prostaglandin synthesis (e.g. paracetamol, opioid analgesics), may also provide pain relief in the dental pain model. The activity of these agents is dependent on the time and method of administration, and may be related to more centrally located analgesic activity, or to peripheral actions other than inhibition of prostaglandin synthesis. In single dose studies it is possible to enhance pain relief by combining analgesic agents of different activities, e.g. ibuprofen 400 mg and codeine 20 mg. Such enhanced activity is also demonstrated by higher doses of certain NSAIDs, e.g. ketoprofen 100 mg. This may reflect the existence of complimentary analgesic activities within a single therapeutic agent. As a clinical research tool the dental pain model has several attributes which suggest that it will continue to be of value in identifying potentially improved analgesic strategies for postoperative pain.