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In a new systematic review from the Cochrane Collaboration,1 acetaminophen is shown to be a safe and effective analgesic for relieving postoperative pain after third molar extraction, and most effective at an optimal dosage of 1000 milligrams. The Cochrane review findings drew news coverage from United Press International,2 Reuters Health3 and other outlets.

The Cochrane Collaboration, an international nonprofit organization, develops evidence-based systematic reviews on the relative effectiveness of health care interventions. The reviewers examined data from 21 randomized controlled trials, involving over 1,900 patients, to determine the optimal dose of acetaminophen and the optimal time for drug administration for pain relief after wisdom tooth extraction. Patients in the included studies received intravenous sedation or anesthesia (local or general), were not taking analgesics at the time of surgery, and were required to report a post-operative pain intensity of at least moderate to severe pain prior to administration of the study medications.

The Cochrane reviewers found that acetaminophen showed “a statistically significant benefit when compared with placebo at both 4 and 6 hours" for pain relief, and that the drug could be taken at six-hour intervals without compromising patient safety. Based on the published evidence to date, the reviewers state that using acetaminophen after third molar surgery is “extremely safe” and has a low incidence of adverse effects.

Importantly, the Cochrane review did not analyze the effectiveness of ibuprofen or other non-steroidal anti-inflammatory drugs (NSAIDs) in relieving pain following third molar extraction, a common oral surgical procedure with demanding pain-control situations. To fill this evidence gap, the Cochrane reviewers are conducting an additional systematic review to compare the relative efficacy of ibuprofen and acetaminophen for the relief of postoperative pain after third molar surgery.

Acute pain management is integral to the provision of optimal dental care and supporting the well-being of patients. While the Cochrane review supports the use of acetaminophen as an effective reliever of postoperative dental pain, randomized trials dating back to the early 1980s have shown that acetaminophen provides significantly greater pain relief than placebo after third molar extraction. For years, acetaminophen has been widely accepted for the treatment of mild to moderate pain.

Oral analgesics are commonly prescribed for a few days following oral surgery or other procedures, after which patients are typically pain-free or can switch to over-the-counter medications (i.e., either lower doses of the same analgesics or different OTC drugs). Dentists should also be aware that an extensive body of pain research supports conventional NSAIDs (e.g., ibuprofen, aspirin) as effective analgesic treatments, including a 2004 systematic review from the University of Oxford.4

Dentists who perform invasive or surgical procedures should take a comprehensive medical history and consult with the patient’s physician as appropriate. In assessing a patient’s health history, conditions that may affect the patient’s ability to metabolize medications are important to consider. For acetaminophen, existing liver damage is one such consideration since it is the primary site of the drug’s metabolism.

Patients should always be reminded to use acetaminophen and other oral analgesics as directed. While 1,000 mg of acetaminophen every six hours approaches the customary maximum recommended daily dose (4,000 mg/day), patients typically exhibit significant reduction in pain after the first post-operative day, suggesting that short-term use may benefit many patients.

For additional information, dentists are encouraged to consult the Oxford League Table of Analgesic Efficacy, the ADA/PDR® Guide to Dental Therapeutics, Fourth Edition, and the list of systematic reviews on pain management.


1. Weil K, Hooper L, Afzal Z, Esposito M, Worthington HV, van Wijk AJ, Coulthard P. Paracetamol for pain relief after surgical removal of lower wisdom teeth. Cochrane Database of Systematic Reviews 2007, Issue 3. Abstract available at: Accessed July 25, 2007.

2. Acetaminophen good for wisdom teeth removal. United Press International, July 19, 2007. Available at: Accessed July 26, 2007.

3. Acetaminophen eases post-wisdom tooth removal pain. Reuters Health, July 30, 2007. Available at: Accessed July 30, 2007.

4. Barden J, Edwards JE, McQuay HJ, Wiffen PJ, Moore RA. Relative efficacy of oral analgesics after third molar extraction. British Dental Journal 2004; 197, 407-411. Available at: Accessed July 30, 2007. 

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Science in the News is a service by the American Dental Association (ADA) to present current information about science topics in the news. The ADA is a professional association of dentists committed to the public's oral health, ethics, science and professional advancement; leading a unified profession through initiatives in advocacy, education, research and the development of standards. As a science-based organization, the ADA's evaluation of the scientific evidence may change as more information becomes available. Your thoughts would be greatly appreciated.

Document Posted July 2007