Investigation of Effects of Hybrid Hyrax‐Mentoplate Treatment in High‐Angle Class III Patients: A Three‐Dimensional, Retrospective Study

OBJECTIVE: This retrospective study evaluated three-dimensional effects of hybrid hyrax-mentoplate (HH-M) orthopaedic treatment in high-angle Class III individuals using Cone Beam Computed Tomography (CBCT) images. MATERIALS AND METHODS: Pre-treatment (T0) and post-treatment (T1) CBCTs of 17 fully compliant high-angle Class III patients (7 males, 10 females, age: 11.7 ± 1.32 years, treatment duration: 12.62 ± 1.7 months) treated with HH-M were analysed. T0 and T1 CBCTs were superimposed from the cranial base using artificial intelligence-based AMASSS module of the 3D Slicer version 5.8.1 software (www.slicer.org). Linear and angular changes were analysed in the sagittal, vertical and transverse planes, alongside three-dimensional landmark displacements and volumetric airway measurements. Significance level was set at p < 0.05. RESULTS: Significant increases occurred in SNA, ANB and Occlusal Plane (OP) to Mandibular Plane (MP) angle (p < 0.001, p < 0.001, p = 0.001, respectively), while Sella-Nasion to OP and Palatal Plane (PP) to OP decreased (p = 0.008, p = 0.008, respectively). Vertical linear measurements remained stable (p > 0.05). All transverse linear measurements increased (p < 0.05). Upper Molar (UM) to PP, Upper Incisor to PP, Lower Incisor to MP and overjet have significantly increased (p < 0.001, p = 0.018, p = 0.048, p < 0.001, respectively). Overbite remained unchanged (p > 0.05). Nasopharynx (p = 0.008) and Middle Pharynx (p = 0.003) volumes significantly increased. CONCLUSION: Despite the significant alterations observed in OP and UM-PP, this technique effectively managed to maintain overall vertical skeletal dimensions without inducing a significant change in other facial height parameters and enhanced the airway volume. Significant expansion occurred across maxillary, nasal and zygomatic levels. HH-M represents an effective orthopaedic treatment approach for high-angle Class III patients.