Association of different socket irrigation solutions with postoperative sequelae after removal of mesioangular middle/low impacted mandibular third molars: a retrospective cohort study

Background Postoperative pain, swelling, and trismus are common after removal of impacted mandibular third molars. Socket irrigation is routinely performed to clean the alveolar sockets, yet comparative evidence for commonly used solutions in clinical practice remains limited. Methods This retrospective cohort study reviewed consecutive patients who underwent removal of a mesioangular middle- or low-impacted mandibular third molar at the Department of Stomatology, The People’s Hospital of Zhongjiang, between January 2020 and January 2025. Patients were categorized into three groups according to the irrigation solution documented in the operative record: compound chlorhexidine, povidone-iodine, or physiological saline. Eligibility criteria and outcome definitions were prespecified. Outcomes included pain score, change in maximum interincisal opening, facial swelling measured by a three-line method, alveolar osteitis, postoperative infection, and postoperative bleeding. Statistical analyses were conducted with SPSS 22.0 (two-sided α = 0.05). Results A total of 102 patients (102 extraction sites) were included. Baseline characteristics were comparable across groups. Postoperative pain scores, reduction in mouth opening, and facial swelling were lowest in the compound chlorhexidine group, intermediate in the povidone-iodine group, and highest in the physiological saline group. Postoperative infection occurred least frequently in the compound chlorhexidine group and most frequently in the physiological saline group. No significant between-group differences were observed in alveolar osteitis or postoperative bleeding. Conclusions In routine clinical practice, socket irrigation with compound chlorhexidine after removal of mesioangular middle/low impacted mandibular third molars was associated with less pain, less trismus, less facial swelling, and a lower postoperative infection rate compared with povidone-iodine and physiological saline.