Date of Award


Document Type


Degree Name

Master of Dental Science (MDS)



Research Advisor

Edward F. Harris, Ph.D.


J. Kendall Dillehay, D.D.S., M.S. Preston D. Miller, D.D.S., M.S.


Airway, CBCT, Development, Growth


Orthodontic treatment effects on the pharyngeal airway have recently become a hot topic in the field of orthodontics. Current literature has shown facial skeletal morphology to be correlated with pharyngeal airway shape and volume. This study used CBCT imaging to identify what, if any, effects two different treatment modalities for correcting Class II malocclusions have on the pharyngeal airway volume. This retrospective study consisted of two groups of Class II patients: 38 patients (15 females, 23 males) treated with the MARA and an Edgewise appliance and 32 patients treated with an Edgewise appliance and Class II elastics. Both pre and post treatment CBCT images (n=140) were analyzed using Dolphin3D© imaging software and a custom cephalometric analysis module. Analysis of the airway was done in three regions defined as 1) the nasopharynx (area superior and posterior to the posterior nasal spine), 2) the oropharynx (inferior to the PNS and superior to the epiglottis), and 3) the total airway volume (nasopharynx + oropharynx). ANOVA models were employed to simultaneously test variables for group differences (sex, treatment, sex + treatment). The results did not identify any significant in-treatment differences between the treatment groups with regard to the pharyngeal airway volume. It was concluded that the dentofacial treatment differences obtained with these two Class II correction methods were not enough to have a significant effect on the pharyngeal airway volume.