because of its ethnic and socioeconomic backgrounds, we can assume that most patients might be within the normal range of body mass index. Apart from the volumetric increase of the oropharynx after mandibular advancement with the Herbst appliance, the minimum cross-sectional area and the sagittal and transversal 2-dimensional measurements of the axial slice of the minimum cross-sectional area of the oropharynx also presented significant increases (P \0.001). However, the height of the oropharynx did not present linear changes during the observation period in either the Herbst appliance group or the comparison group. Measurements were performed by the same investigator, using Dolphin Imaging Software (Dolphin Imaging & Management Solutions, Chatsworth, Calif), according to the method described elsewhere, 1 within the anatomic boundaries of the oropharynx described in this article. We have provided a Table with the 2-dimensional changes of the oropharynx, between T0 and T1 of both groups.