Abstract Purpose The purpose of this study is to compare the opioid requirement and pain intensity after surgeries of mandibular fractures with administration of dexmedetomidine by two approaches of infusion and single bolus.Methods In this double-blind clinical trial, the participants were randomized and matched in terms of age and gender in two groups (infusion and bolus). In both groups, the amount of narcotic used, hemodynamic indices, oxygen saturation, and pain intensity were collected based on the ten-point Visual Analogue Scale (VAS) at 7 time points for 24 h. SPSS version 24 software was used for data analysis. A signifcance level of less than 5% was considered.Results A total of 40 patients were included in the study. There was no signifcant diference between the two groups in terms of gender, age, ASA class, and duration of surgery (P>0.05). There was no signifcant diference between the two groups in terms of nausea and vomiting and subsequently receiving anti-nausea medication (P>0.05). The need for opioid consumption after surgery was not diferent in two groups (P>0.05). Infusion of dexmedetomidine reduced postoperative pain more rapidly than its single bolus dose (P<0.05). However, over time, there was no signifcant diference between the two groups in terms of changes in oxygen saturation variables (P>0.05). Homodynamic indices including heart rate, systolic blood pressure, and diastolic blood pressure in the bolus group were signifcantly lower than the infusion group (P<0.05).Conclusion Administration of dexmedetomidine in the form of infusion can reduce postoperative pain better than bolusinjection, with less probability of hypotension and bradycardia.  Keywords Postoperative pain · Open reduction · Dexmedetomidine

Loghman Ebrahimi is a renowned figure in the field of oral and maxillofacial surgery. Hailing from Tabriz, Iran, Ebrahimi has made significant contributions to the field through his work at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tabriz University of Medical Sciences. His expertise and dedication have earned him recognition both locally and internationally, making him a respected figure in his field.