Association Of Cranial Base Morphology, Hyoid Bone Position And Pharyngeal Airway Depth In Different Sagittal Skeletal Malocclusions: A Cephalometric Study

Abstract

Introduction: The hyoid bone connects the cranial base, mandible, tongue, and airway. Its position changes with different craniofacial patterns and skeletal malocclusions. Since airway size is influenced by mandibular position and cranial base structure, understanding this relationship is important for orthodontic diagnosis and treatment planning. This study aimed to evaluate and compare the position of the hyoid bone and airway dimensions in Class I, II, and III skeletal patterns.

Methods: This retrospective study included 60 lateral cephalograms of subjects aged 15–30 years. They were divided equally into Class I, II, and III groups based on ANB angle and App–Bpp values. Skeletal, angular (NSAr, C3HyD, SArHy, NSHy), airway (D1–D5), and horizontal hyoid (H1–H4) measurements were recorded. Statistical analysis was done using ANOVA, t-tests, and Pearson correlation.

Results: Significant differences were found among the groups in skeletal measurements, airway dimensions (D1, D4, D5), and horizontal hyoid parameters (H1, H2). Class II subjects showed reduced airway space and a vertical growth pattern, while Class III subjects showed increased horizontal dimensions. NSHy differed significantly between groups. Gender differences were minimal. Positive correlations were found between NSAr–NSHy and SArHy–NSHy, while NSAr–SArHy showed a negative correlation.  

Conclusions: Skeletal pattern affects hyoid position and airway size. Class II subjects tend to have reduced airway space, whereas Class III subjects show increased dimensions. Evaluating these relationships is important during orthodontic diagnosis.