Graduation Date

Fall 12-17-2021

Document Type


Degree Name

Master of Science (MS)


Medical Sciences Interdepartmental Area

First Advisor

Sundaralingam Premaraj

Second Advisor

Peter J Giannini


The purpose of this study was to evaluate the effect of orthodontic treatment with and without extractions of teeth on the upper airway dimension and morphology. Records of 40 consecutively treated patients who received orthodontic treatment with or without dental extractions were evaluated. Pre-and post-treatment volumes, minimum cross-sectional areas, and linear dimensions of oropharyngeal airways were quantified using InVivo Dental 6.0 (Anatomage, San Jose, CA). Additionally, pre and post CBCT images of the upper airways were superimposed on each other using voxel-based registration and fixed coordinate system using 3D Slicer 4.1.1 ( and ITK-SNAP ( While the volumes of the upper airway and minimum cross-sectional areas were reduced in the extraction group compared to the non-extraction group, the difference between different treatment modalities was not statistically significant. (P-value>0.05). Morphologically, 80% of the patients who received orthodontic treatment with tooth extraction and maximum anchorage protocol showed either posterior airway translocation or reduction of more than 1 mm in the anterior aspect of the oropharynx. Interestingly, in the extraction group, the oropharynx was either moved anteriorly or enlarged in the anterior segment in 40% of the patients. Present findings show that there is not sufficient evidence to conclude that the orthodontic treatment with dental extractions would negatively impact the upper airway dimensions or minimum cross-sectional areas. There is no uniform trend in the upper airway morphological changes that can be attributed to any of the treatment variables.