Accuracy of 3D simulation in soft tissue change after orthognathic surgery in class III malocclusion: Influence of...

This study aimed to evaluate the accuracy of 3D soft tissue prediction with Simplant O&O software in skeletal Class III patients who received double-jaw orthognathic surgery (OGS). The influences of different vertical facial patterns on the accuracy of surgical prediction were also assessed. Sixty consecutive skeletal class III patients treated with bimaxillary surgery and orthodontic treatment were included. Patients were divided into the high-angle (HA) group and low-angle (LA) group according to the mandibular plane angle. Cone-beam computerized tomographs were acquired before surgery and after debonding. All patients received 3D virtual surgical planning. The accuracy of soft tissue prediction was calculated in terms of 3D regional soft tissue changes between the preoperative simulation and debonding. Independent t-test, chi-square test were used to test for intergroup differences, in combination with. Pearson correlation, Spearman correlation and multiple logistic regression. 3D soft tissue simulation in Class III patients provided an overall clinical acceptable accuracy (mean error <2.0 mm). However, the chin area is less predictable (mean simulation error 1.63 ± 1.64 mm and 1.47 ± 1.21 mm in HA and LA group respectively). The predicted anterior movement of soft tissue in the cheek and lower lip regions were often underestimated. Although the simulation accuracy between the high-angle group and low-angle groups were generally comparable, the upper lip region prediction showed a higher accuracy in the high-angle group compared to the low-angle group. In conclusion, the accuracy of 3D soft tissue prediction should be viewed carefully, and further validation is recommended to fully understand its clinical utility in optimizing surgical outcomes.