Abstract: Objective To explore the impact on hard tissue after preoperative modeling and bimaxillary anterior subapical osteotomy for the treatment of bimaxillary protrusion. Methods The subjects included 20 patients with bimaxillary protrusion who underwent anterior subapical osteotomy of both the maxilla and mandible, and simultaneous genioplasty, from September 2003 to October 2014. Based on model surgical design and an occlusal guide plate, new hard tissue relationships were established for the patients. In addition, the pre- and postoperative cephalometric radiographs were systematically analyzed. Results All the surgical incisions healed by first intention with no infection or osteonecrosis. Significant differences were observed in the pre- and postoperative values of the hard tissue parameters, except for SGn-FH and Co-MP. The most obviously significant differences were seen in Id-Pog-Go (P<0.001). Postoperative follow-up lasted for 12-36 months. All patients eventually achieved normal jaw relationships, tooth arch forms and Spee curves. No evident irregularities of teeth arrangement or abnormal occlusal relationships were observed. All patients were satisfied with their postoperative facial appearance, except for one patient who underwent repeat surgery because of relapse. Conclusion With the use model surgical, orthognathic surgery, a simple and time-saving technique, can be used to correct bimaxillary protrusion with satisfactory postoperative hard tissue relationship and facial esthetic appearance, and minimal postoperative complications.

Key words: Bimaxillary protrusion, Orthognathic surgery, Cephalometric, Model surgery