Surgical simulation based on changes in pre- and predicted postsurgical occlusion can be defined as “occlusion-based” segment mobilization . This concept represents the 3D repositioning of skeletal segments without including orthodontic movements in computerized simulations, especially in cases of only mandibular surgery. For example, while performing the bilateral sagittal split ramus osteotomy for correcting asymmetric mandibular prognathism after using classical presurgical orthodontics, occlusion-based simulation would be helpful for simulating postoperative outcomes. Based on the simulated postoperative occlusion and intercuspation, distal mandibular segments would be mobilized. However, these movements cannot guarantee optimized skeletal symmetry . Therefore, additional contouring surgery would be required to achieve optimal skeletal symmetry in the mandible.
In summary, the system for soft tissue-based surgical simulation needs improvement to reflect individual variation and differences in soft tissue characteristics. Skeletal-based segment mobilization can readily be used for initial STOs, surgery first approaches, or two-jaw surgery cases. Occlusion-based segment mobilization can be used for final STOs or mandibular surgery-only cases in which there will be limited orthodontic movement after orthognathic surgery.
Computerized 3D surgical simulation improves not only the accuracy of the surgical treatment of facial asymmetry, but also the esthetic outcomes. These computerized systems improve the overall system of surgical planning, the surgery itself, and the evaluation process. The proper application of adequate computerized 3D simulation concepts for orthognathic surgery is essential for successful results.