Assessment of respiratory muscle strength and airflow before and after microimplant-assisted rapid palatal expansion.

OBJECTIVES: To assess alterations in respiratory muscle strength and inspiratory and expiratory peak flow, as well as skeletal and dental changes in patients diagnosed with transverse maxillary deficiency before and after microimplant-assisted rapid maxillary expansion (MARPE).

MATERIALS AND METHODS: Twenty patients (13 female and 7 male) were assessed by respiratory tests in three different periods: T0 initial, T1 immediately after expansion, and T2 after 5 months. Tests included: maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), oral expiratory peak flow, and inspiratory nasal flow. Cone-beam computed tomography measurements were performed in the maxillary arch, nasal cavity, and airway before and immediately after expansion.

RESULTS: There was a significant increase in MIP between T0 and T2 and MEP between T0 and T1 ( P <.05). Oral and nasal peak flow increased immediately after and 5 months later, especially in patients with initial signs of airway obstruction ( P <.05). In addition, after expansion there was a significant enlargement of the nasal cavity, alveolar bone, and interdental widths at the premolar and molar region. Molars tipped buccally ( P <.05) but no difference was found in premolar inclination. MARPE increased airway volume significantly.

CONCLUSIONS: Skeletal changes promoted by MARPE directly affected airway volume, resulting in a significant improvement in muscle strength and nasal and oral peak flow.