Abstract
<title>Abstract</title> <p> Purpose To evaluate the efficacy of computer-aided navigation (CAN) in improving mandibular contour symmetry during bimaxillary orthognathic surgery with concurrent mandibular contouring, and to compare its accuracy and aesthetic outcomes with conventional double-splint techniques. Methods A retrospective cohort study was conducted in 60 patients (30 per group) who underwent bimaxillary orthognathic surgery combined with mandibular contouring. Group A received navigated surgery using the AccuNav-A system for real-time guidance of maxillomandibular complex repositioning and mandibular osteoplasty. Group B underwent conventional surgery with double splints, where mandibular contouring was performed based on the surgeon’s experience. The primary outcome was the three-dimensional (3D) discrepancy of reference points at the inferior border of the mandible (RPIBM) between the actual postoperative result and the preoperative virtual plan. Secondary outcomes included facial aesthetic scores assessed by blinded clinicians on a 0–10 scale. Results The mean 3D discrepancy was significantly smaller in Group A than in Group B (1.91 mm vs. 4.03 mm, <italic>P</italic> < 0.001). Group A also showed significantly smaller deviations from the mid-sagittal, Frankfort horizontal, and coronal planes. Postoperative facial aesthetic scores were significantly higher in Group A (9.55 ± 0.81) than in Group B (7.82 ± 0.68, <italic>P</italic> = 0.01), with comparable baseline scores ( <italic>P</italic> = 0.12). No major complications were observed in either group. Conclusion Computer-aided navigation significantly improves the accuracy of mandibular contouring osteoplasty and achieves better postoperative mandibular symmetry and facial aesthetics than conventional double-splint techniques. CAN is a valuable adjunct for orthognathic surgery, particularly in patients requiring precise symmetrical bone reduction. Clinical trial registration This study is a retrospective analysis of routine clinical data. All patients received standard surgical care according to institutional protocols; no intervention was prospectively assigned for research purposes. Therefore, this study does not meet the definition of a clinical trial under ICMJE or WHO ICTRP guidelines, and clinical trial registration is not applicable. </p>