Computer simulation and rapid prototyping for the reconstruction of the mandible.

Augmented-reality environments, that is, computer graphics merged with 3-dimensional representations of anatomic regions generated from imaging modalities (mainly computed tomography [CT] and magnetic resonance imaging), have their background in well-known and well-established conventional image-guided surgery, which we can describe as the “first generation of navigation.” 1-3 Although the surgeon is solely supplied with “information,” this technology significantly expands the range of the intraoperatively available information. Nevertheless, it does not provide any kind of haptic feedback, and the transfer of all the computer information is accomplished manually during the treatment of the patient. Technical progress led to the integration of rapid prototyping techniques (3-dimensional stereolithography) in image-guided surgery workflows and therefore can add “haptic” information to the computerbased visualization. Therefore we can call such approaches the “second generation of navigation.” Simulation and planning of surgical interventions by use of stereolithographic models can contribute to the optimization of treatment and can also enhance quality management in craniomaxillofacial surgery, because the specific anatomic situation of each patient can be comprehensively analyzed preoperatively. Navigation technology enables the precise transfer of the