Background: The extraction of the mandibular third molar is a common oral surgical procedure. Postoperative complications after third molar surgery such as swelling, pain, and trismus have a considerable influence on the quality of life in patients. Methods to alleviate these complications have been the focus of a lot of studies. Aim: To evaluate the surgical wound and postoperative complications after third molar surgery by comparing two different flaps: triangle flap and comma-shaped flap. Materials and Methods: a clinical trial with a split-mouth design. Thirty healthy patients were subjected to surgical extraction of both impacted mandibular third molars, located in a similar clinical and radiographic position. Two different flaps are used: triangle flap and comma-shaped flap. Result: The parameters of pain, swelling, and trismus in the comma-shaped flap group were greater than in the triangle flap group on postoperative days 1 and 2, with a statistically significant difference (p<0.05). On day 7, no significant interference was found between the 2 groups for all parameters of pain, swelling, and trismus (p>0.05). Conclusion: The comma-shaped flap is better than the triangle flap concerning postoperative pain, swelling, and trismus. Key words: Lower third molar surgery, split-mouth design, comma-shaped flap, triangle flap