We compared the clinical efficacy of orally administered valdecoxib and piroxicam for the prevention of pain, trismus and swelling after removal of horizontally and totally intrabony impacted lower third molars. Twenty-five patients were scheduled to undergo removal of symmetrically positioned lower third molars in two separate appointments. Valdecoxib (40 mg) or piroxicam (20 mg) was administered in a double-blind, randomized and crossed manner for 4 days after the surgical procedures. Objective and subjective parameters were recorded for comparison of postoperative courses. Both agents were effective for postoperative pain relief (N = 19). There was a similar mouth opening at suture removal compared with the preoperative values (86.14 +/- 4.36 and 93.12 +/- 3.70% of the initial measure for valdecoxib and piroxicam, respectively; ANOVA). There was no significant difference regarding the total amount of rescue medication taken by the patients treated with valdecoxib or piroxicam (173.08 +/- 91.21 and 461.54 +/- 199.85 mg, respectively; Wilcoxon test). There were no significant differences concerning the swelling observed on the second postoperative day compared to baseline measures (6.15 +/- 1.84 and 8.46 +/- 2.04 mm for valdecoxib and piroxicam, respectively; ANOVA) or on the seventh postoperative day (1.69 +/- 1.61 and 2.23 +/- 2.09 mm for valdecoxib and piroxicam, respectively; ANOVA). The cyclooxygenase-2 selective inhibitor valdecoxib is as effective as the non-selective cyclooxygenase inhibitor piroxicam for pain, trismus and swelling control after removal of horizontally and totally intrabony impacted lower third molars.