Orthodontic--surgical treatment and respiratory function: rhinomanometric assessment.

BACKGROUND: Several correlations between morphological and/or positional alterations of the jaws and respiratory functional impairments have been reported. Nasal airway obstruction represents a critical issue with no clearly defined gold standard as for its measurement. Rhinomanometry was adopted by multiple Authors to evaluate whether patients with malocclusion developed respiratory functional changes after an orthodontic-surgical treatment. However, there are contrasting findings in the literature regarding the possibility of improving the respiratory function by means of surgically-assisted rapid palatal expansion (SARPE) or bimaxillary repositioning of the bony bases. METHODS: Ten patients aged from 18 to 30 years and scheduled for orthodontic-surgical treatment of maxillary constriction volunteered as participants for this study. Orthognathic surgery consisted in: 1) SARPE in 4 patients; 2) Le Fort I down fracture combined with a bilateral sagittal split osteotomy (BSSO) in 6 patients. All patients underwent a computerized rhinomanometric test before treatment (T0) and 40 days after surgery, at the time of the inter-maxillary splint removal (T1). Specifically, all 10 patients received AAR evaluations, while 6 patients received both active anterior (AAR) and active posterior rhinomanometry (APR). RESULTS: Both AAR and APR tests showed a decrease in mean nasal resistance following the intervention. As for the AAR, a difference of 0.19 Pa/s/cm3 was found. The difference found for APR at a reference pressure of 75 Pa was 0.24 Pascal/s/cm3, while for APR at 150 Pa it was 0.20 Pa/s/cm3. CONCLUSIONS: This study helps to confirm respiratory benefits obtainable after mono and bi-maxillary orthognathic surgery.