Accuracy of CAD/CAM Mandibular Reconstruction: A Three-dimensional, Fully Virtual Outcome Evaluation Method

Purpose: Computer-aided design/computer-aided manufacturing (CAD/CAM) methods for mandibular reconstruction have improved both functional and morphological results. We evaluated the accuracy of the CAD/CAM method for mandibular reconstruction and assessed the quantitative and qualitative reproducibility of virtual preoperative planning.

Materials And Methods: A total of 34 consecutive patients treated with mandibular reconstruction using the CAD/CAM method between January 2011 and October 2017 were included in this study. The accuracy of the reconstruction was assessed using the automated Hausdorff distance function of the simulation software, which set the postoperative mesh as the target. This made it possible to calculate the minimum error, the maximum error, and the mean error for each reconstruction in exactly the same way and with the same settings as the difference between the postoperative mesh and virtual planning. Finally, the coloured quality mapper function was applied to superimposition of the STL files, allowing us to visually render the obtained data on differences between preoperative planning and surgical outcome.

Results: The average mean error obtained after performing an accuracy evaluation of our reconstructions was 1 mm (range 0.4-2.46 mm). Based on the colour map areas, the maximum error was located in the symphysis area. The body and ramus areas showed the greatest accuracy in terms of planning reproducibility.

Conclusion: This is the first study to assess the three-dimensional reproducibility of virtual planning using the CAD/CAM method for mandibular reconstruction, in a homogeneous sample of 34 cases. Our data suggest that CAD/CAM microvascular reconstruction can result in a very high degree of reproducibility. This occurs in complex areas as well as the condylar region and in the case of extensive mandibular reconstructions.