Correlation between skeletal changes by maxillary protraction and upper airway dimensions

Objective: To describe the correlation between the skeletal changes induced by maxillary protraction treatment and the sagittal airway dimension associated with tongue, soft palate, and hyoid bone position in skeletal Class III children. Materials and Methods: Twenty Class III patients (5 boys, 15 girls; mean age, 9.4 +/- 1.8 years) treated with a maxillary protraction appliance were included in this study. Pretreatment and posttreatment cephalometric radiographs were analyzed; linear and angular measurements were performed by an expert orthodontist. The correlation between treatment changes in craniofacial morphology and those in upper airway, tongue, soft palate, and hyoid position was evaluated by Pearson's correlation analysis. Results: A significant increase in maxillary forward displacement, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. Simultaneously, nasopharyngeal airway measurements PNS-ad1 and PNS-ad2 significantly increased by 1.4 mm and 1.9 mm, respectively. A correlation analysis revealed that maxillary protraction had a positive relationship with PNS-ad1 and PNS-ad2. Conclusions: The nasopharyngeal airway dimensions can be improved in the short term with maxillary protraction in skeletal Class III children. (Angle Orthod. 2011;81:426-432.)