Fully Digital vs. Conventional Planning in Bimaxillary Orthognathic Surgery: Effects on 3D Accuracy and Surgical Efficiency

Background: Accurate transfer of the surgical plan is essential in bimaxillary orthognathic surgery, where small discrepancies between planned and postoperative skeletal positions may influence functional and aesthetic outcomes. This study compared the three-dimensional (3D) accuracy and time efficiency of conventional and fully digital planning workflows using CBCT-based evaluation. Methods: This retrospective comparative study included 100 adult patients with skeletal Class II or III malocclusion treated by Le Fort I osteotomy combined with bilateral sagittal split osteotomy (BSSO). Patients were allocated to conventional planning (n = 50) or fully digital planning using IPS CaseDesigner (n = 50). Planned and postoperative CBCT datasets were superimposed using voxel-based cranial base registration. Linear deviations at A-point and Pogonion, total RMS error, planning time, and operative time were analyzed. Results: Mean deviations were lower in the digital group at A-point (1.28 ± 0.28 mm vs. 1.63 ± 0.36 mm) and Pogonion (1.49 ± 0.42 mm vs. 1.95 ± 0.44 mm) (p < 0.001). Total RMS deviation was reduced in the digital workflow (1.39 ± 0.39 mm vs. 1.80 ± 0.54 mm; p < 0.001). Planning and operative times were significantly shorter in the digital group (p < 0.001). Moderate correlations were observed between time variables and 3D deviations. Conclusions: Fully digital planning showed improved 3D accuracy and significantly reduced planning and operative times compared with conventional methods, while maintaining clinically acceptable deviations.