The relationship of vertical skeletofacial morphology to oropharyngeal airway shape using cone beam computed tomography: Possible implications for airway restriction

Abstract

Objective: To determine if the shape of the oropharyngeal airway is related to the vertical morphology of the skeletofacial complex, including the hyoid bone. Materials and Methods: Cone beam computed tomography scans from 50 pretreatment adult orthodontic records were used to obtain skeletal and airway measurements. Linear regression statistics were used to compare soft tissue variables to hard tissue predictor variables. Results: Transverse airway widening was significantly increased when the distance between the hyoid and vertebrae was reduced; when the three-dimensional (3D) facial axis angle decreased (became more vertical); when the 3D mandibular plane angle increased; when the width of the hyoid increased, or when the calculated length of the geniohyoid decreased. Conclusions: A laterally elliptical airway-found when the face is more vertical and when the hyoid is closer to the cervical vertebrae-is hypothetically more resistant to collapse. Patients with a retrognathic, skeletal deep bite and a rounded oropharynx should be identified and corrected early to prevent potential airway problems. (Angle Orthod. 2014;84:548-554.)

Airway increase after open bite closure with temporary anchorage devices for intrusion of the upper posteriors: Evidence from 2D cephalometric measurements and 3D magnetic resonance imaging

“…They found that the airway narrowing in apnoeic patients predominantly occurred in the lateral dimension but not in A‐P dimension because of a thicker lateral pharyngeal wall in apneic patients. This finding supports previous studies, which have suggested laterally elliptical airways resist collapse better than sagittally elliptical airways. However, when we measured the ratio of lateral airway width (width) to A‐P airway length (length) to evaluate changes in the airway shape, we found that the ratio decreased after open bite closure.…”

Are three-dimensional airway evaluations obtained through computed and cone-beam computed tomography scans predictable from lateral cephalograms? A systematic review of evidence

“…This poor correlation is contributed to dramatic differences in airway shape that exist in the oropharyngeal and hypopharyngeal spaces. 14 The present study reveals the higher correlations for upright CBCT and upright LC than supine CT and upright LC imaging, which may be explained by positional changes in the airway. Reductions in airway antero-posterior dimensions and cross-sectional area have been demonstrated in the supine posture.…”

“…We hypothesize that because the upper airway has a spherical or elliptical shape, 13,14 the linear measurements from 2D images may predict the cross-sectional area and volume of the airway with a significantly smaller dose of radiation exposure than 3D imaging modalities. However, to the best of our knowledge, no reported systematic review is available on the correlation between CBCT/CT and LC airway assessment.…”

CBCT in orthodontics: assessment of treatment outcomes and indications for its use

“…120,121 However, the possibility that volume or cross-sectional area may be a better measure of airway contriction has been proposed, which requires CBCT, rather than conventional images. 122 While CBCT is generally used to image mineralized tissues, it can also be used to accurately image the airway, which allows clinicians to measure cross-sectional area, minimum cross section and total volume of the patient's airway [123][124][125] (Figure 11). Initial investigations on airway patency, function and disorders utilizing CBCT have provided preliminary answers, including dimensions of normal airway anatomy in adults, 122,126 relationship Dentomaxillofac Radiol, 44,20140282 birpublications.org/dmfr of 2D to 3D measurements, 127 differences in airway morphology in subjects with OSA and non-OSA, [128][129][130] the effects of extractions on 3D pharyngeal volume and structure, 131 and the consequences of RME [132][133][134][135] and orthognathic surgery on airway dimensions.…”