Early treatment of Class III malocclusion by maxillary protraction facial mask: effects on craniofacial structures and upper airway dimensions

The aim of our study was to evaluate the effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures and to describe the correlation between the skeletal changes and the sagittal airway dimension associated with tongue, soft palate, and hyoid bone position in skeletal Class III children. A total of 40 patients with Class III malocclusions were evaluated by the use of lateral cephalograms. Pretreatment and posttreatment cephalometric radiographs were analyzed; linear and angular measurements were performed by the same orthodontist. The effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures were evaluated by Student's T test and 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 test. A significant increase in maxillary forward growth, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. The statistical analysis revealed that maxillary growth had a significant positive effect on the superior upper airway sagittal dimension. The nasopharyngeal airway dimensions can be improved in the short term with maxillary protraction in skeletal Class III children.