No abstract

Background A new distraction osteogenesis assembly system comprising a fully customized CAD/CAM-based fixation unit and ready-made distraction unit was developed. The aim of this study was to introduce our new distraction system and to evaluate its accuracy level in a sampled mandibular distraction osteogenesis. Methods Our system consists of a fully customized CAD/CAM-based fixation plate unit with two plates for each moving and anchoring part, and a ready-made distraction unit with attachment slots for fixation plates. The experimental distractions were performed on 3D-printed mandibles for one control and two experimental groups (N = 10 for each group). All groups had reference bars on the chin region and teeth to measure distraction accuracy. The control group had the classical ready-made distraction system, and experimental groups 1 and 2 were fitted with our new distraction assembly using a different distractor-positioning guide design. All distracted experimental mandibles were scanned by CT imaging, then superimposed on a 3D simulation to get their discrepancy levels. Results The measured 3D distances between the reference landmarks of the surgical simulations and the experimental surgeries for the three groups were significantly different (p < 0.0001) by statistical analysis. The errors were greater in the control group (with a total average of 19.18 ± 3.73 mm in 3D distance between the simulated and actual reference points) than those in the two experimental groups (with an average of 3.68 ± 1.41 mm for group 1 and 3.07 ± 1.39 mm for group 2). The customized distraction assembly with 3D-printed bone plate units in group 1 and 2, however, did not show any significant differences between simulated and actual distances (p > 0.999). Conclusion Our newly-developed distraction assembly system with CAD/CAM plate for the distraction osteogenesis of the mandible produced a greater level of accuracy than that of a conventional distraction device. The system appears to address existing shortcomings of conventional distraction devices, including inaccuracy in vector-controlled movement of the system. However, it also needs to be further developed to address the requirements and anatomical characteristics of specific regions.

The results of surgical simulation need to be transferred to the operation table with precision and confidence. We want to introduce a three-dimensional (3D)-printed maxillary cutting guide to perform the simulation-based maxillary osteotomy, interference removal, and the device guide for maxillary orthognathic surgery. The orthognathic simulation is performed with a horizontal osteotomy line and the maxillary segmental movement on a computed tomography (CT)-based 3D model. The maxillary cutting guide is designed as a band-shaped template encompassing the osteotomy line, bone interference area, and guiding holes. The design is exported to a 3D printer and the cutting guide is printed with biocompatible resin materials. The cutting guide was applied to 45 orthognathic surgeries. It could assist the easy and accurate osteotomy as planned and eliminate the repeated empirical checks of the premature interference site while preventing excessive bone reduction. This device guides the surgeon to place the osteotomy line, predict and remove the bony interferences, and place holes for additional surgical devices for maxillary orthognathic surgery.