Pharyngeal airway volume and shape from cone-beam computed tomography

Relationship to facial morphology

Grauer, Dan
Cevidanes, Lucia S.H.
Styner, Martin A.
Ackerman, James L.
Proffit, William R.

^aPostdoctoral fellow, Department of Orthodontics, School of Dentistry, University of Notrh Carolina, Chapel Hill, NC
^bAssistant professor, Department of Orthodontics, School of Dentistry, University of Notrh Carolina, Chapel Hill, NC
^cAssistant professor, Department of Computer Science, School of Arts and Sciences, University of Notrh Carolina, Chapel Hill, NC
^dAdjunct professor, Department of Orthodontics, School of Dentistry, University of Notrh Carolina, Chapel Hill, NC
^eKenan professor, Department of Orthodontics, School of Dentistry, University of Notrh Carolina, Chapel Hill, NC

^∗Reprint requests to: Dan Grauer, Department of Orthodontics, UNC School of Dentistry, Chapel Hill, NC 27599-7450.

Supported by NIDCR R01 DE005215.

The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.

Submitted, October 2007; revised and accepted, January 2008.

American Journal of Orthodontics and Dentofacial Orthopedics 136(6):p 805-814, December 2009.

Introduction:

The aim of this study was to assess the differences in airway shape and volume among subjects with various facial patterns.

Methods:

Cone-beam computed tomography records of 62 nongrowing patients were used to evaluate the pharyngeal airway volume (superior and inferior compartments) and shape. This was done by using 3-dimensional virtual surface models to calculate airway volumes instead of estimates based on linear measurements. Subgroups of the sample were determined by anteroposterior jaw relationships and vertical proportions.

Results:

There was a statistically significant relationship between the volume of the inferior component of the airway and the anteroposterior jaw relationship (P = 0.02), and between airway volume and both size of the face and sex (P = 0.02, P = 0.01). No differences in airway volumes related to vertical facial proportions were found. Skeletal Class II patients often had forward inclination of the airway (P <0.001), whereas skeletal Class III patients had a more vertically oriented airway (P = 0.002).

Conclusions:

Airway volume and shape vary among patients with different anteroposterior jaw relationships; airway shape but not volume differs with various vertical jaw relationships. The methods developed in this study make it possible to determine the relationship of 3-dimensional pharyngeal airway surface models to facial morphology, while controlling for variability in facial size.