Sagittal airway dimensions following maxillary protraction: a pilot study

The relationship between changes in the position of the maxillary structures caused by maxillary protraction therapy and airway dimensions have not been investigated as comprehensively as the accompanying skeletal changes. The purpose of this study was to examine the effects of rapid palatal expansion (RPE) used in conjunction with maxillary protraction headgear on the sagittal dimension of the airway. The treatment sample consisted of 19 Class III patients (12 girls, 7 boys) with a mean age of 10.51 +/- 1.15 years, presenting with maxillary retrognathism. A cap splint type rapid palatal expander that had hooks between the upper lateral and canine teeth was used intraorally, and a Petit type facemask device extraorally, for an average of 6.78 +/- 0.93 months. Pre- and post-treatment cephalometric radiographs were evaluated. The results of the study revealed that point A moved anteriorly. The palatal plane showed a counter-clockwise rotation matched by the clockwise rotation of the mandible and an accompanying decrease in SNB angle. The vertical parameters showed a statistically significant increase. The head was in a more extensive position in relation to the cervical vertebrae. The nasopharyngeal airway measurements (PNS-ad1, PNS-ad2) showed an increase of 2.71 +/- 3.35 and 3.03 +/- 2.37 mm, respectively. These results demonstrated that limited maxillary widening together with protraction of the maxilla, improve nasopharyngeal but not oropharyngeal airway dimensions in the short term.