Upper airway volume changes in patients treated with rapid maxillary expantion: a CBCT study

Rapid Maxillary Expansion (RME) is an orthopedic treatment used to correct the transverse Deficit of the maxilla. Most often this defect is diagnosed in mouth breathing patients. The treatment with RPE increases the volume of the upper airways and decreases their resistance, promoting physiological nasal breathing. The aim of this study is to measure the the volume of the upper airways by means of Cone-beam Computed Tomography (CBCT) to evaluate the anatomical space where the major effects of RME occurred. Materials and methods: 24 subjects (mean age, 10.17± 1.75 years) treated with McNamara-type rapid palatal expander were selected. Results: RPV showed a significant increase delta T1_T0: 680.75 mm, P<0.005). No significant changes were found in TV (delta T1-T0: 452.92 mm±3091.7 mm, P>0.05) and in RGV (delta T1-T0 166.92 mm ±666.97 mm, P>0.05). Conclusions: In this study patients showed a statistically significant increase in RPV after RPE treatment. The CBCT scans provide only quantitative volumetric data, so it would be appropriate to determine with a functional examination (for example, rhinomanometry) the clinical significance of the obtained results. Standardization of the radiological protocol should be improved to over come certain limitations such as tongue posture during scan recording, swallowing and breathing control. Further studies are needed to evaluate the long- term stability of these effects on the airways.