Position of Hyoid Bone in Different Classes of Skeletal Malocclusion Using Cone-Beam Computed Tomography

Background: The goal of this study was to evaluate and compare the position of the hyoid bone (HB) in different classes of malocclusion using cone-beam computed tomography (CBCT). Gender differences were investigated across the studied groups.
Methods and Materials: The study included 120 CBCTs acquired from equal groups of males and females and evenly distributed among the three classes of malocclusion. The age of the participants ≥ 18 years. Multiplanar reconstruction were generated in axial, sagittal, coronal, and 3D views using Ez3D-i software. Several measurements points including SNA, SNB, ANB, H-Me, H-EB, C3-Me, HC3-Me, H-PNS, HB-H, and H-V were measured following standardized definitions. The data was entered and analyzed using the SPSS. Significance was set a value of P < 0.05.
Results: Across gender-based differences were observed in HB positioning. Males demonstrated greater distances between the third cervical vertebra (C3) and HB (C3-HB, p < 0.001), as well as between C3 and the Menton point (C3-Me, p < 0.001), compared to females. The position of HB compared to the maxilla (H-PNS), its horizontal position (HB-H), and its vertical position (H-V) were all significantly different between males and females. No significance gender differences were found for H-Me, H-EB, and HC3-Me. Significant statistically differences were observed among skeletal Classes groups for H-Me, H-EB, C3-Me, HC3-Me, H-PNS, HB-H, and H-V (p < 0.05). Class III group demonstrated the greatest H-Me value, while Class II showed the lowest.
Conclusions: The study demonstrated significance difference in HB position among male and females and across skeletal Classes. Males showed significantly greater distances and positional differences involving the C3, Me point, and HB compared to females. Additionally, the position of HB varies across different skeletal classes. Class III group exhibited the most inferior and anterior HB position, whereas Class II showed the least.