Simulation of orthognathic surgery in camouflage treated skeletal class ii borderline cases: Predictability of dentofacial changes

Objective: The aim of this study is to determine the common features of skeletal and soft tissue angular and linear cephalometric measurement values in borderline cases with skeletal Class II malocclusion. Materials and Methods: The records of 120 patients with Class II malocclusion who underwent camouflage treatment, archived digitally by the Department of Orthodontics at Çukurova University Faculty of Dentistry, were reviewed. A total of 29 patients who met the inclusion criteria and were between the ages of 14-19 at the start of treatment were included in the study. Reference parameters were measured using Dolphin Imaging Version 11.95 (Dolphin Imaging and Management Solutions, Chatsworth, CA, USA) on lateral cephalometric radiographs and extraoral profile photographs taken at "treatment start," "treatment end," and "treatment outcome prediction" stages. These measurements included "Facial Axis Angle," "Facial Angle," "Facial Taper," "Convexity Angle," "Soft Tissue Convexity Angle," "Lower and Upper Lip to E-Plane Distance," and "Mandible and Maxilla to Nasion Perpendicular Distance." Statistical analysis of the data was performed using SPSS (Statistical Package for the Social Sciences) 25.0 software. Results: The values for Facial Axis Angle, Facial Angle, Soft Tissue Convexity Angle, Mandible to Nasion Perpendicular Distance, and Mandibular Corpus Length were higher in the orthognathic surgery simulation compared to the results of camouflage treatment (respectively, p<0.001; p=0.008; p<0.001; p=0.007; p<0.001). The values for Convexity Angle and Upper Lip to E-Plane Distance were lower in the orthognathic surgery simulation compared to the results of camouflage treatment (respectively, p<0.001; p=0.004). The mean cephalometric values at the start of treatment for skeletal Class II patients with borderline characteristics were found to be 4.33º for ANB angle, 6 mm for overjet, 74.2 mm for Mandibular Corpus Length, 85.9º for Facial Axis and Facial Angles, 129.5º for Soft Tissue Convexity, and -2.60 mm for Lower Lip to E-Plane Distance. Conclusion: In light of our study findings, it is possible to suggest that skeletal Class II malocclusion patients who underwent camouflage treatment and achieved dentofacial measurements that coincide with both the post-camouflage treatment and norm values during orthognathic surgery simulation can be considered as borderline cases. Additionally, we concluded that the measurements obtained from 2D software can be effectively used for treatment outcome prediction based on these findings. Keyworlds: Orthodontic camouflage treatment, Orthognatic surgery, Skeletal Class II malocclusion, Borderline cases, 2D simulation, Prediction