The control of pain, swelling and trismus in patients undergoing oral and maxillofacial surgery is frequently performed through the administration of non-steroidal anti-inflammatory drugs (NSAIDS). The present study aims to evaluate in a double blind, randomized and crossover manner the clinical efficacy of ketoprofen (immediate release - 100 mg) and ketoprofen in association with omeprazole (modified release - 200 mg ketoprofen with 20 mg omeprazole) in 50 patients aged 18 years or older that require removal of both lower third molars symmetrically positioned. After collection, data will be analyzed by means of graphs and tables to allow the appropriate analyses. Paired t-test will be used to compare the duration of surgeries. Nonparametric Wilcoxon test will be used for the analysis of "rescue medication" and postoperative pain parameters (visual analog scale). Data of "mouth opening" and "swelling" will be statistically analyzed through analysis of variance (ANOVA) followed by Tukey's test for multiple comparisons. Statistical significance will be set at 5%. Results will be presented as mean ± standard deviation of the mean.