# Assessment of Hyoid Bone Position and its Correlation With Airway Dimensions in Different Sagittal Malocclusions Using Cone Beam Computed Tomography

## TL;DR

This study uses CT scans to show how the position of the hyoid bone and airway size differ in people with different jaw alignments.

## Contribution

The study reveals new correlations between hyoid bone position and airway dimensions in different skeletal malocclusions using CBCT.

## Key findings

- Oropharyngeal volume was significantly higher in Class I compared to Class II malocclusions.
- Hyoid bone in Class II individuals was positioned more posteriorly and horizontally distant from the true vertical.
- Males had larger nasopharyngeal volumes and inferiorly positioned hyoid bones compared to females.

## Abstract

Objectives: To evaluate the changes in the position of the hyoid bone in different skeletal malocclusions and correlate it with pharyngeal airway dimension using cone beam computed tomography (CBCT).

Materials and methods: Ninety healthy adult subjects between 18 and 25 years with normo divergent facial pattern (FMA range 21° and 28°) from the postgraduate orthodontic clinic of the Institution. The subjects were divided into three groups consisting of 30 patients each, on the basis of the ANB angle. Each group was subdivided into two according to gender to evaluate if any sexual dimorphism exists in airway dimensions and hyoid bone position.

Results: Oropharyngeal volume was maximum in Class I group (15.18) and least in Class II group (12.06), which was statistically significant with a p value of 0.015. Horizontal distance from highest point of the hyoid bone and true vertical in Class II group had the highest value of 21.51 and Class I had the least value of 17.31, which was statistically significant with p value of 0.027. Vertical measurement between the hyoid bone and the posterior nasal spine (PNS) in Class III subjects was around 57.01, and Class I subjects had the least value of 51.20. Nasopharyngeal volume was higher in the male group with a t value of −2.798 and was statistically significant.

Conclusion: The hyoid bone is posteriorly positioned in Class II skeletal pattern. Oropharyngeal volume was least in Class II skeletal base individuals. In males, pharyngeal volume was larger than females, and the hyoid bone was placed inferiorly compared to females.