Oropharyngeal 3-dimensional changes after maxillary expansion with 2 different orthodontic approaches.

Introduction The objective of this research was to compare the oropharyngeal volume and minimal cross-sectional area (MCA) changes after maxillary expansion using either the Damon system or Hyrax appliances as assessed through cone-beam computed tomography (CBCT) imaging. Methods Patients aged between 11 and 17 years with skeletal maxillary transverse discrepancy in need of maxillary expansion were included and allocated randomly into 1 of the 2 treatment groups, Damon or Hyrax. Patients underwent CBCT imaging at 2 time points: T1, after initial clinical evaluation before treatment, and T2, after completion of full orthodontic treatment. The CBCT data were assessed using Dolphin software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). In addition, a qualitative assessment of breathing function was done using the modified Nasal Obstruction and Septoplasty Effectiveness Scale questionnaire. Results A statistically significant increase in the oropharyngeal volume (2.23 mL; P = 0.005) and MCA (29.72 mm2; P = 0.007) after the completion of treatment (T2 – T1) for the Hyrax group was suggested. No statistically significant difference was found in the Damon group for volume (1 mL; P = 0.311) and for MCA (7.32 mm2; P = 0.643). In addition, no statistically significant difference was found in the breathing function in both treatment groups (P >0.05). Conclusions Hyrax expansion followed by fixed appliances produced more dimensional upper airway changes at the oropharyngeal level than the Damon system approach. No breathing functional changes were noted in either samples.