Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 9 3 2023 04 04 128 134 Goran Fatah Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Sulaimani, Sulaimani, Iraq. Bayad Mahmood Faris Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Sulaimani, Sulaimani, Iraq. 2022 09 29 2022 12 23 Aim: To evaluate the relative ability of 4mg dose of preoperative Dexamethasone, administered submucosally, to reduce the postoperative pain, swelling and trismus after third molar surgery. Materials and Methods: The total 40 patient required surgical removal of a single mandibular third molar were included and divided into two groups, the experimental group (20 cases) received intraoperative submucosal injection of 4mg Dexamethasone buccally around the tooth at three points after the onset of anesthesia and the control group (20 cases) received no drugs. The maximum interincisal distance and facial contours were measured at baseline and at post-surgery days 2 and 7. The measurement of pain was done using visual analog scale (VAS). Results: There was a statistically significant reduction in the severity of postoperative edema in the experimental group by the second postoperative day. While both groups saw a reduction in discomfort and trismus, there were no statistically significant differences between them. Conclusion: The findings support submucosal injection of Dexamethasone (4mg) to decrease postoperative edema. Low-dose Dexamethasone injection at the surgical site enhances drug concentration at the injury site without loss owing to diffusion or excretion. The submucosal technique was significantly effective in reduction of postoperative swelling and trismus. Keywords: Dexamethasone; Third molar; Pain; Trismus; Edema. https://jcr.tums.ac.ir/index.php/jcr/article/view/416 https://jcr.tums.ac.ir/index.php/jcr/article/download/416/359