Effects of rapid maxillary expansion on nasal cavity dimensions and airway resistance

Abstract

Background: Rapid maxillary expansion is a common treatment for posterior cross-bites that has also shown to improve nasal breathing.Methods: Thirteen oral breather patients with posterior cross-bite were studied. Treatment consisted in rapid maxillary expansion with a fully bonded appliance including a bite-block and a hyrax expansion screw. Before and after treatment, CT scans and active anterior rhinomanometry were performed to each patient. Data was analyzed with the non-parametric Wilcoxon statistical test and correlation between palatal expansion and increase of airflow in each patient was assessed.Results: The CT scan showed that transversal dimensions were significantly increased (P<0.001) in most areas after treatment, considering the right and left side separately. Rhinomanometry also showed statistical differences (P<0.001) in all parameters studied when compared before and after treatment. Positive correlation was observed between palatal expansion and increase of airflow.Conclusions: All patients improved oral breathing habit clinically and there is also statistical evidence that the nasal cavity increased its transversal dimensions, measured by CT scan and that patients increased their airflow through the nasal cavity, measured by rhinomanometry.