Real-time orthognathic surgical simulation using a mandibular motion tracking system.

We developed a new orthognathic surgical simulation system able to predict both occlusal correction and mandibular repositioning in three dimensions. This system uniquely integrates the real motion of the dental cast model with the virtual motion of the reconstructed cranio-facial model. The skeletal change of the mandibular osteotomy is simulated on the PC monitor while the occlusal change is confirmed by checking the cast model on the simulator. The simulation process is easily repeated and the operator can make several attempts to determine the final mandibular position. The occlusal relationship at the simulated mandibular posture is registered and the occlusal wafer splint, which ensures intermaxillary fixation, is fabricated on the simulator. This surgical simulation system appears to satisfy clinical demands well and is an important facilitator of communication between orthodontists and surgeons. Here, we outline the system and apply it to a demonstration case of orthognathic surgery.