Background: Mandibular fracture osteosynthesis comes with mechanical and thermal assaults to surrounding tissues resulting in the sequelae of pain, trismus, and oedema. Dexamethasone is known to reduce these sequelae; pain, swelling and trismus, with varying outcomes, and the lack of a standardized regimen for its optimal effect in maxillofacial surgery remains a cause of concern to researchers.
 Objective: To compare two dexamethasone intervention time points in reducing post-operative sequelae of mandibular fracture osteosynthesis
 Methods: A total of 102 subjects with mandibular body fractures in the age bracket of 20-60 years were recruited into the study and divided into preoperative, intraoperative, and control groups. 4mg of dexamethasone was injected via the submucosal route into the intact mucogingival area below the fracture line, one hour before making the incision in the preoperative group, at the time of the incision for the intraoperative group, and injection of the same volume of 0.9% normal saline preoperatively for the control group. Following osteosynthesis, postoperative sequelae, and complications were assessed on postoperative days 1, 3, and 7.
 Results: There was a reduction in pain, swelling, and trismus in both test groups compared to the control with a significant reduction observed in the intraoperative group.
 Conclusion: Our results showed that the administration of 4mg submucous dexamethasone reduces postoperative sequelae after mandibular fracture osteosynthesis with the intraoperative administration resulting in a significant reduction in postoperative pain.