Evalution of mandibular asymmetry in patients with class II subdivision malocclusion

Objective: The objective of this thesis is to assess the presence of mandibular asymmetry in patients with Class II subdivision malocclusion by performing angular and linear measurements on two-dimensional radiographic images and frontal photographs. Materials and Methods: Orthodontic records of 297 patients with Class II subdivision malocclusion from the digital archive of the Department of Orthodontics at the Faculty of Dentistry, Cukurova University were reviewed. A total of 70 patients aged 15-20 years meeting the inclusion criteria, were included in the study. Panoramic radiographs (PR), postero-anterior radiographs (PASR), and frontal photographs were analyzed using the Dolphin Imaging Version 11.95 software (Dolphin Imaging and Management Solutions, Chatsworth, CA, USA) to measure reference parameters. The parameters included Condylar Height (Co-SN), Ramus Height (Co-Go, Pre-Go'), Corpus Length (Go-Me, Go'-Me'), Total Mandibular Length (Co-Me), Condylion Horizontal Plane Distance (Co-HRL), Condylion Vertical Plane Distance (Co-VRL), Antegonion Horizontal Plane Distance (Ag-HRL), Gonion' Horizontal Plane Distance (Go'-HRL), Antegonion Vertical Plane Distance (Ag-VRL), Gonion' Vertical Plane Distance (Go'-VRL), Gonial Angle (Co-Go-Me, Pre-Go'-Me'), Gonion-Crista Galli-Menton Angle (Go-CrG-Me), and Gonion'-Glabella-Menton' Angle (Go'-G-Me'). The Asymmetry Index (AI) for each parameter was calculated using the asymmetry index developed by Habets. Statistical analysis was performed using SPSS version 25.0. Results: In PR analysis, the values for Co-SN, Co-Go, Go-Me, and Co-Me on the Class I side were significantly higher compared to the Class II side (*p=0.001, p<0.001, p<0.001, p<0.001, p<0.001*). Conversely, the Co-Go-Me value was notably lower on the Class II side (*p<0.001*). In PASR analysis, Co-HRL, Ag-HRL, Co-Go, and Go-Me values were significantly higher on the Class I side (*p<0.001*), while Ag-VRL and Co-Go-Me values were higher on the Class II side (*p<0.001*). The AI values of the Pre-Go' and Go'-Me' parameters evaluated in the photographs were found to be significantly lower compared to the AI values of the Co-Go and Go-Me parameters evaluated in the radiographic images (p<0,001) The AI values for Co-Go and Go-Me in the photographs were significantly lower compared to radiographic analyses (p<0,001). Conclusion: The majority of the Class II subdivision malocclusion patients in our study demonstrated findings indicating the presence of mandibular asymmetry. However, this skeletal asymmetry appears to be less reflected in soft tissues. Keywords: Class II subdivision malocclusion, mandibular asymmetry, panoramic radiograph, postero-anterior radiograph, frontal photograph, asymmetry index.