Cephalometric Analysis in Studying the Position of the Hyoid Bone and the Upper Respiratory Tract Status in Patients with Occlusion Issues.
Authors: Domenyuk D. , Kochkonyan T. , Domenyuk S. 
Published: July 2024

Occlusion sagittal issues come accompanied with morphological disorders affecting the facial skeleton, the shape and size of dental arches, the temporomandibular joint elements, disturbed chewing function, swallowing, breathing, speech production, as well as change involving the posture balance. Cephalometric analysis offers the most reliable and promising option in studying the hyoid bone position and the upper respiratory tract (URT) status. Aim of study.This study was carried out aiming at improving the diagnostics reliability, when dealing with patients featuring occlusion pathology, through studying the hyoid bone position and the upper respiratory tract status relying on the cephalometric analysis of the head lateral telerentgenograms (TRG). Materials and methods.The study involved 76 children aged 15-17 bearing the diagnosis of Distal occlusion (DO); the patients were divided into 2 subgroups – Subgroup 1 (n=41) where the patients had DO combined with sagittal incisive disocclusion and Subgroup 2 (n=35) who featured DO along with deep incisive disocclusion. Adolescents (n=34) revealing physiological occlusion were the comparison group. The cephalometric analysis of the head profile TRGs (OnDemand3D™ Dental software; CEPH module) employed linear, angular and index parameters in order to identify individual features of the craniofacial structure as well as the os hyoideum position. The degree of the URT narrowing at the nose and oropharynx level was determined via 3D reconstruction of cone beam computed tomograms (CBCT) based on a visual colorimetric scale. Results and discussion.The cephalometric analysis of the linear, angular and index indices of the head lateral TRGs obtained through examining adolescents with distal occlusion revealed mutual effects of gnathic, cranial and dental alveolar factors. The hyoid bone upward displacement in adolescents with DO, if compared to children with physiological occlusion, was obvious through a statistically significant (p≤0.05) decrease in the Me values of H-S (by 13.69%-14.55%); H-RGn (by 21.91%-22.57%); H-MR (by 47.57% and 54.76%); <H-Me-MP (by 32.38%-34.98%). As far as the os hyoideum backward shift is concerned, it was to be seen from a significant (p≤0.05) decrease in the Me values of H-CIII (by 25.42%-26.05%) with an increase in <HGo-NM (by 9.94%-10.34%). The changes identified in the hyoid bone topography in children with DO came combined with a dynamic narrowing of the URT, that manifesting itself through a significant (p≤0.05) reduction in the total volume of the respiratory tract and the cross-sectional area. Conclusion.The URT volume measurement carried out with CBCT, the hyoid bone topography evaluation, identifying the tongue position and size along with doing the same for the cervical vertebrae and for the posture compensation degree, allow the dentist to take an objectively reliable approach to diagnosing and treating dental pathologies, which, in turn, will improve the overall quality of dental treatment. The retroposition of the lower jaw results in a compressed upper respiratory tract, which will facilitate the development of compensatory changes in the cranio-vertebral joint, that expressing in the anterior position of the head. Identifying due normative parameters and the status of the URT, as well as the connection with the dental structure status, for cases falling within norm or disturbed occlusion range, will require further research.