Award Date


Degree Type


Degree Name

Master of Science (MS)


Dental Medicine

First Committee Member

Tanya Al-Talib

Second Committee Member

James Mah

Third Committee Member

Karl Kingsley

Fourth Committee Member

Amei Amei

Number of Pages



Objective: The aim of the study is to determine whether there is a relationship between the risk for daytime sleepiness in adults with Class I and Class II malocclusion and the airway volume, minimum cross-sectional area, and shape at the minimum cross sectional area.

Introduction: Sleep disordered breathing (SDB) is a category of conditions defined by airway complications while a person is sleeping. Obstructive sleep apnea (OSA) is the most common of these disorders and is defined as the presence of repeated episodes of complete or partial airway obstruction, which may be associated with loud snoring and daytime sleepiness. Daytime sleepiness has been identified in 50% of obstructive sleep apnea patients. Prevalence of OSA in the adult population suggests that 9% of females and 24% of males are affected. Some of the risk factors for OSA in adults include obesity, age, and nasal blockage. Mandibular retrognathism and obesity are the major risk factors for OSA. In addition, the neck circumference is a confirmed risk factor for OSA in patients.

OSA treatment includes CPAP (Continuous positive air pressure) which is considered the gold standard for treatment. Other treatments include oral appliances and in some cases, orthognathic surgery for mandibular advancement.

Materials and Methods: This retrospective study included 87 patients 18-60 years of age. The patient’s skeletal classification was determined using the Dolphin imaging software. Patients were classified into either skeletal class I or class II based on ANB and Wits values. ANB angle of 0° to 5° is considered class I and ANB angle of >5° is considered class II. The patient’s risk for daytime sleepiness was identified using the Epworth Sleepiness Scale. A score of 11 or greater in the Epworth Sleepiness Scale indicates a high possibility of excessive daytime sleepiness. A score of less than 11 indicates a low possibility of excessive daytime sleepiness. Then Anatomage’s InVivo software was used to measure the total airway volume, minimum cross-sectional area, and shape of the airway at the minimum cross-sectional area.

Results: There were significant interactions in the total airway volume (p

Conclusions: Skeletal classification and risk have significant impact on airway volume and minimum cross-sectional area, but they do not have an impact on cross section shape. Patients with skeletal Class II have a smaller mean difference in airway volume and minimum cross-sectional area than patients who are skeletal Class I in high risk vs. low risk.


Class I; Class II; Cone beam computed tomography; Daytime sleepiness; Sleep apnea



File Format


Degree Grantor

University of Nevada, Las Vegas




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