Purpose: The purpose of this study is to support the position of the AAO by demonstrating that the oropharyngeal volume does not decrease as a result of premolar extractions and orthodontic treatment.

Materials and Methods: Cone-beam CT’s were obtained for twenty-seven orthodontic patients before and after treatment. Nine patients were treated with four premolar extractions, and eighteen treated non-extraction. Total oropharyngeal airway volume and minimum area of constriction were measured using InVivo Anatomage Software.

Results: The initial and final airway volumes of the non-extraction group were correlated (p = 0.61). The total airway volume in the non-extraction cases showed a significant increase (p = .037).

Conclusion: There was no significant change in oropharyngeal volume in Class II patients that underwent orthodontic treatment with extractions, however; patients that were treated non-extraction had a significant increase in oropharyngeal volume. There was no significant change in area of minimum constriction in either group.