3D virtual planning in Orthognathic Surgery and CAD/CAM Surgical Splints generation

Trabalho final do 5º ano com vista à atribuição do grau de mestre no âmbito do ciclo de estudos de Mestrado Integrado em Medicina Dentária apresentado à Faculdade de Medicina da Universidade de Coimbra.Objective: The purpose of this study is to test a new technique for 3-dimensional (3D) virtual planning in orthognathic surgery, with prediction of postoperative results on hard tissues and manufacture of CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) surgical splints using Nemoceph 3D-OS software (Software Nemotec SL, Madrid, Spain) on one clinical case. Materials and Methods: The clinical protocol consists of 3D data acquisition by cone-beam computerized tomography (CBCT) and surface scanning of the plaster dental models, with subsequent fusion of the two datasets. The ‘‘virtual patient’’ thus created undergoes virtual surgery and a simulation of postoperative results on hard tissues is produced. Surgical splints are manufactured using CAD/CAM technology, in order to transfer the virtual surgical plan to the operating room. Intraoperatively, both types of surgical splints are compared. A second set of 3D images is obtained after surgery to obtain linear measurements to compare with the measurements obtained when predicting postoperative results virtually. Results: It was found a high similarity between both types of surgical splints with equal fitting on the dental arches. The post-surgical prediction results were encouraging but not sufficiently accurate. The linear measurements reflect some large discrepancies between the actual surgical outcomes and the predicted results from the 3D virtual simulation, but caution must be taken in the analysis of these results due to several variables. Conclusion: This study confirmed the clinical feasibility of a computer-assisted orthognathic surgical protocol incorporating virtual planning and its transfer to the operating room using CAD/CAM fabricated surgical splints. Postoperative predictions still lack some reliability and further study with larger sample size is required to confirm the results obtained in this study, as well as further progress in the development of technologies for 3D image acquisition and improvements on software programs to simulate postoperative changes on soft tissues