The skeletal class II and class III its related to functional and sthetics problems. Among the functional changes are alterations of mastication, of speech and temporomandibular joint symptoms. Also the interest for the airway changes has been increased in the last years.

The change that occurs at the caliber of extrathoracic airway following orthognathic surgery has been widely studied in the sagittal diameter. It is frequently observed that after orthognathic surgery, when there is mandibular advancement, sagittal caliber in the airway increases. On the contrary, in the case of skeletal class III when the surgical procedure includes a mandibular setback osteotomy, it may cause a decrease in the airway caliber.

The aim of this study is to evaluate the changes in the airway caliber following orthognathic surgery, measuring the increase or decrease in sagittal plane determining if this change occurs at the expense of transverse caliber.

This study includes 20 patients with skeletal class I and II, in analysis of the airway area considering the axial plane in two anatomical points which are considered key in the permeability of the extrathoracic airway:

• a.

  Most convexe aspect of posterior border of the soft palate—posterior pharyngeal wall.

• b.

  Most convexe aspect of tongue base—posterior pharyngeal wall.

This analysis use a Cone-Beam CT Kodak 9500 equipment. The first study was 7–10 days before the surgical procedure and the second study was perform three months after surgery.

Computacional analysis and data collection were done using OsiriX v. 3.8 software.

Conflict of interest: None declared.