Evaluation of effects of a modified asymmetric rapid maxillary expansion appliance on the upper airway volume by cone beam computed tomography

BACKGROUND/PURPOSE: The rapid maxillary expansion is accepted as the gold standard for the treatment of unilateral posterior crossbite in growing children. This study used cone beam computed tomography (CBCT) to evaluate the effects of a modified asymmetric rapid maxillary expansion (ARME) appliance on the upper airway volumes. MATERIALS AND METHODS: A modified ARME appliance was used on 12 adolescent male patients (mean age: 13.92 ± 0.82 years) with a class I skeletal relationship and posterior unilateral crossbite. Lateral cephalometric measurements and upper airway volume were evaluated using CBCT images. The posterior airway volumes of the oropharyngeal and nasopharyngeal airways were measured. RESULTS: Cephalometric measurements showed significant (P < 0.05) posterior rotation of the mandible. There was no significant movement of the maxilla according to the cranial base on the sagittal plane. Nasopharyngeal and oropharyngeal airway volumes increased significantly (P < 0.05). CONCLUSION: The results of this study demonstrate that treatment with the modified ARME has no significant effect on the maxilla but may increase the upper airway volume.