CBCT Analysis of the Hyoid and Pharyngeal Airway Changes in Class III Patients With Orthognathic Surgery.

Abstract

Aim: This study was designed to investigate the response of the respiratory structures to orthognathic surgery in patients with Class III malocclusion, with a specific emphasis on the vertical placement of the hyoid bone. The correlations of these changes were also analysed, followed by further subgroup analyses based on preoperative conditions.

Materials and methods: Dolphin software was used to obtain cephalometric landmarks, airway and hyoid bone measurements from pre- and postoperative CBCT scans of 31 patients. Statistical analyses included paired t-tests and Pearson's correlation analysis.

Results: Stomatological mandibular values and the nasopharynx height showed significant changes. Pearson's correlation identified significant correlations between changes in B and H horizontal coordinates (p < 0.05), as well as between changes in H longitudinal coordinates and specific airway dynamics (p < 0.05). Patients with a lower preoperative hyoid position experienced a more pronounced decrease in hypopharyngeal airway volume after surgery compared to those with a higher preoperative hyoid position, as evidenced by the significant mean differences and p values (p < 0.01).

Conclusions: Class III patients experienced airway constriction following orthognathic surgery, particularly those with a lower preoperative hyoid bone position, who showed a more significant decrease in hypopharyngeal airway volume postsurgery compared to those with a higher preoperative hyoid position. These findings underscored the importance of individualised surgical planning and highlighted the need for further research with dynamic assessments to optimise respiratory outcomes.