Accuracy of 3-dimensional soft tissue prediction for orthognathic surgery in a Chinese population

Objectives: This study aims to determine the validity of a 3D planning software in predicting the soft tissue outcome of Chinese patients undergoing orthognathic surgery for correction of Skeletal III dentofacial deformity.Methods: Pre-and post-operative 3D facial stereophotogrammetric scans and cone beam computed tomogra-phy were taken for 10 Chinese patients who had underwent orthognathic surgery. The pre-operative 3D facial scan was integrated with the pre-operative CBCT using the ProPlan CMF software. The simulated soft tissue 3D face was then compared with the actual 3D facial scan obtained at least 6 months postoperatively. Two outcome measures were computed as follows (i) mean absolute difference between meshes (ii) percent-age of points where the distance between the two meshes is 2mm or less.Results: The mean absolute difference between the predicted and actual soft tissue surface meshes for the full face and the 6 anatomic regions ranged from 0.72mm to 1.42 mm. The mean absolute distance between the meshes for all the anatomic regions were within 2 mm (p<0.05). The percentage of mesh points with less than 2mm error ranged from 72.5% to 92.5%. The accuracy of soft tissue prediction, assessed using mean absolute distance for the full face, was significantly correlated to the amount of sagittal surgical movement (r=0.707, p=0.022). The lower lip was also found to be the least accurate.Conclusions: Using ProPlan CMF, the accuracy of 3D soft tissue predictions for bimaxillary orthognathic sur-gery in Chinese Skeletal III patients were clinically satisfactory.(c) 2021 Published by Elsevier Masson SAS.