Background: This study evaluates the volumetric dimensional changes in the upper airway level of the nasopharynx and oropharynx and the stability of the tongue and hyoid bone after Lefort I Osteotomy of maxillary advancement osteotomy and bilateral sagittal backward branch in patients with Class III skeletal deformity. 19 adult patients (12 men–7 women), Class III skeletal (average age), CT cone-beam was performed (cone-beam CT) one week before the procedure surgery, three months later and over 18 months later the surgery.

Objectives: (1) Determine the position of base of tongue, hyoid bone and the volume of the upper airway before orthognathic surgery. (2) Determine the position of base of tongue, hyoid bone and the volume of airway four months after orthognathic surgery. (3) Relate the upper airway volume, the position of the hyoid bone and the base of the tongue, after 18 months of orthognathic surgery. (4) To determine the relationship of the positions of the anatomical structures in times, T0, T1, T2. (5) Determining the change in the volumetric capacity of the upper airway at the times T0, T1, T2, relating changes in anatomical structures T0, T1, and T2.

Methodology: A descriptive–prospective study with a sample of 19 patients, its made measurements on TC Cone beam to determinate and comparate and determinate de changes in the position in T0, T1, T2.

Results: The results of this study shows an increase in the volume of the upper airway in T1 respect T0, with a reposition of tongue and hyoid bone in T2 near the position on T0 Conclusions: The bi-maxillary surgery causes a tendency to increase the total size volume of the upper airway, and the tongue and hyoid bone tends to reposition to the initial point before the surgery. Keywords: oropharyngeal airway; tongue; hyoid; orthognatic surgery