Our aim was to determine the presence of a correlation between the nasal airway skeletal transverse dimension and air intake changes in rapid maxillary expansion treatments.

Sixty-one patients with maxillary transverse deficiency (11–17years old) were randomly allocated into three groups (two treatment groups – tooth- [hyrax] or bone-borne [miniscrew-implant-based] expander – and one control group). Cone-beam computed tomography scans (CBCT) were obtained from each patient as well as acoustic rhinometry (AR) readings. Specifically, in AR, airway volume up to minimum cross-sectional areas (Vol. 1&2) and minimum cross-sectional areas (Min. 1&2) in the nasal cavity were measured. Records were obtained at two time points (initial T₁ and at removal of appliance at 6months T₂). CBCTs were analyzed using AVIZO software and landmarks were placed on the nasal base. Descriptive statistics were compiled and student's t-test was used.

Of the 480 pairings measured, only 9 showed statistically significant positive correlations between T₁ and T₂. Correlation data were highly variable in all categories, showing no clear tendencies. No statistical difference was found when comparing all groups in terms of airway changes.

With very few positive correlations observed and otherwise highly variable data, no really conclusive finding was obtained to suggest any realistic correlation between changes in the skeletal dimensions and changes in the nasal airway.