Virtual orthodontic surgical planning to improve the accuracy of the surgery-first approach: a prospective evaluation

Purpose: We developed an innovative computer-assisted method to increase the accuracy of the surgery-first (SF) approach by linking the virtual orthodontic planning (VOP) with the virtual surgical planning (VSP). Materials and Methods: Fifteen consecutive patients were enrolled from 2013 to 2015. All 15 patients had initially undergone cone-beam computed tomography (CBCT; 15 x 15 field-of-view) and intraoral digital scanning of the dental arches. The DICOM (Digital Imaging and Communications in Medicine) data set and STL files were processed using the SimPlant O&O platform (Dentsply-Sirona, York, PA), which facilitates skeletal, dental, and soft tissue modeling and subsequent realization of the VOP/VSP. The VSP was reproduced using computer-aided design and computer-aided manufacturing surgical splints, and the VOP was realized via postoperative orthodontic treatment. At the end of treatment, all the patients underwent repeat CBCT and digital scanning of the dental arches, and the new data sets were compared with the original data sets to determine the deviations. To evaluate skeletal accuracy, we assessed all points within an arbitrary range of -2 to +2 mm. To evaluate dental accuracy, the arbitrary range was -0.8 to +0.8 mm. Results: The average duration of orthodontic treatment was 17.9 months. The accuracy of maxillary treatment averaged 0.0702 +/- 2.0724 mm and that of mandibular treatment, 0.2811 +/- 1.9993 mm. The average upper and lower dental arch accuracy was -0.0029 +/- 1.125 and -0.0147 +/- 1.263 mm, respectively. The maxillary surgery accuracy was 75.3% and that of mandibular surgery 74.0%, both within the -2 to +2-mm range. The upper and lower arch accuracy was 58.86 and 51.53%, respectively, both within the -0.8 to +0.8-mm range. Conclusions: The use of the VOP/VSP improved the diagnostic and therapeutic SF preoperative planning. VOP contributed significantly in this context. The accuracy of skeletal repositioning was acceptable; however, the VSP should be rendered more reproducibly in the future to minimize the need for orthodon- tic compensation and to maximize the advantages of SF. (C) 2019 American Association of Oral and Maxillofacial Surgeons