Paracetamol for pain relief after surgical removal of lower wisdom teeth.

BACKGROUND Paracetamol has been commonly used for the relief of postoperative pain following oral surgery. In this review we investigated the optimal dose of paracetamol and the optimal time for drug administration to provide pain relief, taking into account the side effects of different doses of the drug. This will inform dentists and their patients of the best strategy for pain relief after the surgical removal of wisdom teeth. OBJECTIVES To assess the beneficial and harmful effects of paracetamol for pain relief after surgical removal of lower wisdom teeth, compared to placebo, at different doses and administered postoperatively. SEARCH STRATEGY We searched the Cochrane Oral Health Group's Trials Register; the Cochrane Pain, Palliative and Supportive Care Group's Trials Register; CENTRAL; MEDLINE; EMBASE and the Current Controlled Trials Register. Handsearching included several dental journals. We checked the bibliographies of relevant clinical trials and review articles for studies outside the handsearched journals. We wrote to authors of the identified randomised controlled trials (RCTs), to manufacturers of analgesic pharmaceuticals, we searched personal references in an attempt to identify unpublished or ongoing RCTs. No language restriction was applied. The last electronic search was conducted on 24th August 2006. SELECTION CRITERIA Randomised, parallel group, placebo controlled, double blind clinical trials of paracetamol for acute pain, following third molar surgery. DATA COLLECTION AND ANALYSIS All trials identified were scanned independently and in duplicate by two review authors, any disagreements were resolved by discussion, or if necessary a third review author was consulted. The proportion of patients with at least 50% pain relief was calculated for both paracetamol and placebo. The number of patients experiencing adverse events, and/or the total number of adverse events reported were analysed. MAIN RESULTS Twenty-one trials met the inclusion criteria. A total of 2048 patients were initially enrolled in the trials (1148 received paracetamol, and 892 the placebo) and of these 1968 (96%) were included in the meta-analysis (1133 received paracetamol, and 835 the placebo). Paracetamol provided a statistically significant benefit when compared with placebo for pain relief and pain intensity at both 4 and 6 hours. Most studies were found to have moderate risk of bias, with poorly reported allocation concealment being the main problem. Risk ratio values for pain relief at 4 hours 2.85 (95% confidence interval (CI) 1.89 to 4.29), and at 6 hours 3.32 (95% CI 1.88 to 5.87). A statistically significant benefit was also found between up to 1000 mg and 1000 mg doses, the higher the dose giving greater benefit for each measure at both time points. There was no statistically significant difference between the number of patients who reported adverse events, overall this being 19% in the paracetamol group and 16% in the placebo group. AUTHORS' CONCLUSIONS Paracetamol is a safe, effective drug for the treatment of postoperative pain following the surgical removal of lower wisdom teeth.