Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Peter Ngan

Committee Co-Chair

Chris Martin

Committee Member

Thomas Razmus

Abstract

Background and Objectives: Much attention has been given to the association of craniofacial skeletal morphology, upper airway dimension, and respiratory function with patients suffering from obstructive sleep apnea. However, much of the information gathered on the aforementioned has been established with the use of 2-Dimensional lateral cephalometry. The objective of this study was to investigate upper airway dimensions among different skeletal patterns using cone-beam computed tomography (CBCT). Methods: A sample of 279 patients who seught orthodontic treatment at the University of Nevada Las Vegas School of Dentistry Department of Orthodontics was included in this study. Pre-treatment multi-slice CBCT scans of these subjects were divided into three sagittal groups: Class I subjects with an ANB angle 0° to 5°, Class II subjects with an ANB angle > 5°, and Class III subjects with an ANB angle < 0°. The CBCT scans were also divided into three vertical groups: normodivergent subjects with a mandibular plane angle 22° to 30°, hyperdivergent subjects with a mandibular plane angle > 30°, and hypodivergent subjects with a mandibular plane angle< 22°. The sagittal and vertical groups were analyzed individually (6 groups) and together (9 groups) to determine if the various combination of skeletal patterns has any effects on airway volume, minimum cross sectional area (CSA), and airway shape. CBCT scans were analyzed using Dolphin Imaging 10.5 Premium and Anatomage In VivoDental(TM) software version 5.1. Data were analyzed using ANOV A, Tukey-Kramer, Student t test, and Wilcoxon/Kruskal-Wallis tests. Results: Significant differences were found among the sagittal groups for airway volume and minimum CSA, p < .05. Class III subjects were found to have the largest airway volume and minimum CSA while Class II subjects were found to have the smallest airway volume and minimum CSA. Minimum CSA was found to have an increasing function of airway volume. CSA increased by 10.23 mm2 for every cc increase in airway volume. No significant differences were found among the vertical groups. However, Class II subjects with hyperdivergent skeletal pattern were found to have the smallest airway volume and minimum CSA. No associations were found between the airway shapes and airway volume when evaluating sagittal and/or vertical skeletal patterns. However, wide airway shapes were shown to have the largest airway volume while long airway shapes were shown to have the smallest airways. Conclusions: Airway dimensions can be affected by craniofacial skeletal pattern. Patients with Class II hyperdivergent skeletal pattern may be more prone to obstructive sleep apnea problems.

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