Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 3 4 2016 12 15 264 267 EN Ata Garajei Department of Oral and Maxillofacial Surgery, School of Dentistry and Department of Head and Neck Surgical Oncology and Reconstructive Surgery, The Cancer Institute, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran . Azadeh Emami Department of Anesthesiology, Iran University of Medical Sciences, Tehran, Iran. 2016 11 26 2016 11 26 Introduction: Postoperative complications such as swelling, pain, and trismus after surgery of the impacted lower third molars are the main concerns of surgeons. Many authors claim that the use of a drain could help control these unpleasent events. The purpose of this study was to evaluate the effect of the use of a surgical drain to control the swelling in impacted lower third molar surgery. Materials and Methods: We had 100 patients of both genders with bilateral impacted lower third molars in comparable positions and with the same degree of surgical difficulty in this study. Both impacted molars were removed in the same session using a surgical drain on one side and without it in the other side. The postoperative swelling was evaluated at 48 hours and 7 days. Results: In the group in which the drain was used, the control of the swelling variable was statistically significant at 48 hours (P = .001) in comparison with the group in which the drain was not used. However, it was not statistically significant at 7 days (P=1.00). Conclusion: The use of the drain helps to control swelling in the acute phase of postoperation. Key words: Surgical drain, Mandibular third molar surgery, Impacted tooth, Postoperative complication. https://jcr.tums.ac.ir/index.php/jcr/article/view/110 https://jcr.tums.ac.ir/index.php/jcr/article/download/110/137