Investigation of Effects of Hybrid Hyrax‐Mentoplate Treatment in High‐Angle Class III Patients: A Three‐Dimensional, Retrospective Study
Gamze Yıldırım, Elvan Önem Özbilen, Fulya ÖzdemirABSTRACT
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 (
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.