The investigators will select 30 patients with symmetrical impaction of third molars, according to Pell and Gregory dental impaction classification, who would be submitted to two surgical procedures, right and left, and in both surgeries dexamethasone 8 mg was administered in the pre-surgery phase, and the use of dexamethasone (12 mg/day) for 3 days on one side and diclofenac sodium (150 mg/day) for 3 days on the other side was continued, in a randomized, double-blind and cross-over trial so that all patients acted as control of themselves (split-mouth). Other drugs used in postoperative period, rescue analgesic and antibiotic therapy will be identical for all patients. The analyzed variables will be the visual analogue pain scale (VAS), total number of consumed analgesics, swelling and trismus (objectively), which were statistically analyzed by means of Student's t-test.