The accuracy of computer-aided design and manufacturing surgical-guide for infrazygomatic crest miniscrew placement

Objectives: Infrazygomatic crest (IZC) surgical guides have been employed to prevent any avoidable complications during miniscrew insertion. The purpose of this study was to evaluate the accuracy of IZC miniscrew placement when using a surgical-guide developed by computer-aided design and manufacturing (CAD/CAM) techniques. Materials and Methods: Ten patients were scanned with cone-beam computed tomography for three-dimensional (3D) planning of IZC miniscrew placements. The upper arches were scanned separately, and virtual miniscrews were placed in the position planned by 3D software. The CAD/CAM surgical guides were designed and fabricated individually to enable accurate miniscrew placement. Subsequently, 20 self-drilling miniscrews were inserted at the right and left IZC areas using 5 CAD/CAM surgical guides (CS group, n = 10) and direct insertion (DI group, n = 10), respectively. Pre- and post-operative digital model images were compared, actual and planned miniscrew positions were superimposed and measured for 3D angular and distance deviations in the two groups. Comparisons between groups were made using the Kruskal–Wallis test. Results: In the CS group, the median coronal and sagittal angular deviations were 2.95 degrees (range 0.34–5.26 degrees) and 2.05 degrees (range 0.38–4.08 degrees), respectively, while the median coronal and apical deviations were 0.39 mm (range 0.24–0.51 mm) and 0.50 mm (range 0.16–0.66 mm). These deviations differed significantly from those of the DI group. Conclusion: The IZC CAD/CAM surgical guide has made it possible to control miniscrew placement with high precision.