Document Type

Thesis

Date of Degree

2010

Degree Name

MS (Master of Science)

Degree In

Stomatology

First Advisor

Axel Ruprecht

Second Advisor

Lina Moreno Uribe

Abstract

Objective

The goal of this project was to define and measure human volumetric airway dimensions with radiographic volumetric three-dimensional imaging and digital reconstruction of the pharynx using cone beam computed tomography to directly correlate these measurements with both normal and developmentally deficient jaw joints and their positions. The volume of the oropharynx was measured by creating a superior border connecting the 3-D midpoint of sella turcica and the posterior nasal spine and extending inferiorly to the level connecting the most infero-anterior point of C3 and the anterior hyoid bone as seen in the multi-planar views of the cone beam computed tomography image. The calculations were accomplished by using 3dMD software.

Further extrapolation of this study'a data may be useful to establish the direct association of obstructive sleep apnea and deficiencies of jaw growth and airway development.

Design

In this retrospective study, 250 subjects were randomly selected from a pool of 800 referred for dental imaging at ddi Imaging Center in Sacramento, California. Digital images were captured using a low-radiation, rapid scanning cone beam computed tomography system (iCAT).

Results

A total of 250 subjects, 163 females and 87 males, were included in this study. Descriptive statistics were applied to the following variables:

1. Assessment of the relationship between total airway volume and several categorically independent variables:

* For total airway volume, no significant difference was found between males and females; between the right temporomandibular positions; between right temporomandibular integrity; or between the left temporomandibular integrity.

* There was a significant difference found between the left temporomandibular positions for total airway volume.

2. Assessment of the relationship between total airway volume and each cephalometric measurement:

* Based on the Spearman correlation test, there were significant increasing relationships between total airway volume and several of the cephalometric measurements (p<0.05).

* Correlation coefficients ranged from 0.13 to 0.22 indicating there were weak correlations between the two variables.

3. Assessment of the relationship between total airway volume and age:

* Based on the Spearman correlation test, there was no significant relationship between total airway volume and age (p=0.8304). In addition, Spearman correlation showed no correlation between total airway volume and sex and skeletal growth pattern tendencies.

Conclusions

Three dimensional images of the airway offer the opportunity to serially examine individuals, acquire airway patency information, and improve the evaluation of sites of airway obstruction. Further studies to determine the effects of pharyngeal stenosis and other regional changes to the oropharynx upon physiologic response may be key to understanding the effects of biomechanical influences upon craniofacial form. Comprehension of structural inter-relationships will also help develop an understanding of how and why adaptive changes in airway shape and volume occur. Airway patency is related to many variables: head posture, the direction of mandibular rotation during growth and development, and hyoid bone position. Further studies may offer an increased understanding of these structural and positional interrelationships.

Keywords

Airway, Cephalometrics, Obstructive sleep apnea, Procrustes analysis, Temporomandibular joint

Pages

ix, 73 pages

Bibliography

Includes bibliographical references (pages 71-73).

Copyright

Copyright 2010 Gayle Tieszen Reardon

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