Single-jaw patient-specific implants in bimaxillary orthognathic surgery: Randomized cross-controlled comparison between maxilla-guided and mandible-guided approach

This randomized trial aims to compare the efficacy of Patient Specific Implants in bimaxillary orthognathic surgery via maxilla-guided or mandible-guided technique, focusing on the accuracy of pre-operative planning transfer in the operating room. Twenty patients with dentoskeletal dysmorphism were enrolled and virtual surgical planning (VSP) was performed. Subsequently, they underwent bimaxillary orthognathic surgery using either a maxilla-guided or a mandible-guided approach, as determined via a blind randomization process. Post-operative CBCT scans were conducted one month after surgery to assess maxillo-mandibular positioning. Finally, a roto-translational rigid body analysis was conducted to compare the initial VSP and the post-operative results. Results revealed high reproducibility with both techniques, maxilla-guided approach demonstrating an increased accuracy in vertical, antero-posterior and total translational repositioning of the maxilla, and the antero-posterior repositioning of the mandible compared to the mandible-guided approach. However, the mandible-guided approach offered greater flexibility in controlling the vertical dimension. The two methods have proven to be largely comparable in terms of mandibular rami positioning. Both techniques exhibited clinically equivalent precision in reproducing the VSP, with no surgical complications observed. In conclusion, while the maxilla-guided approach exhibited generally lower discrepancies in the reproduction of the VSP, both techniques were deemed equally effective in bimaxillary orthognathic surgery.