Aim: Three-dimensional (3D) reconstructions of cone beam CT (CBCT) data facilitate preoperatively planning of orthognathic surgery in three dimensions. Superimpositioning of the pre- and postoperative 3D data enable comparison of the hard tissue changes in bimaxillary procedures in a 3D virtual environment. The aim of this study was to evaluate the in virtual 3D preoperative planning of bimaxillary procedures with the postoperative surgical outcome.

Materials and methods: In a prospective study 20 dysgnathic patients were treated with a bimaxillary procedure (Le Fort I osteotomy and BSSO (Hunsuck technique)). The virtual planning was transferred to the actual operating room with a tooth-born intermediate and final wafer, based on the 3D virtual planning. After a voxel-based superimpositioning of the virtual planning with the postoperative 3D data sets, skeletal changes of the maxilla and the mandible, such as pitch, roll and yaw, were observed in the 3D virtual operating room (Maxilim ^® ).

Results: All clinical and virtual assessments were performed by one OMF surgeon. The virtual plannings revealed that more patients than anticipated during the clinical assessment showed asymmetrical features. Especially corrections needed in the horizontal plane (yaw) were underestimated. Both the planned and postoperative translational and rotational movements of the maxilla and mandible were clearly visualized in the 3D virtual operating room. The maxillary movements in the sagittal plane were difficult to accomplish exactly according to the virtual planning.

Conclusions: Superimpositioning of pre- and postoperative 3D datasets is a useful tool to evaluate the virtual 3D planning and the surgical outcome of bimaxillary procedures.

Conflict of interest : None declared.