[Upper airway changes in patients with skeletal Class III maxillary retrognathia after rapid maxillary expansion and protraction: a meta-analysis].

PURPOSE This study was to evaluate the upper airway changes in patients with skeletal Class Ⅲ maxillary retrognathia after rapid maxillary expansion and protraction. METHODS An electronic search in PubMed, Cochrane Library, Embase, CNKI, CBM, VIP and Wanfang was performed until March 1st, 2018. According to the inclusion and exclusion criteria, two investigators respectively reviewed the literature and selected eligible studies, then assessed the risks of bias and extracted the data of the included studies. The extracted data were quantitatively analyzed with Revman 5.3 software. RESULTS A total of 12 studies were included for meta-analysis. The results showed that, after treatment the nasopharyngeal volum(P 0.05) and hypopharyneal volume (P>0.05) existed. The nasopharyngeal airway dimensions had increased significantly with the following measurements: PNS-ad1 (P 0.05), IPS(P>0.05). CONCLUSIONS Rapid maxillary expansion and protraction can increase nasopharyngeal volume and sagittal airway dimensions in skeletal Class Ⅲ subjects with maxillary retrusion. It may be suggested that rapid maxillary expansion and protraction have the potential to reduce the risk of obstructive sleep apnea syndrome in children with maxillary retrusion by enlarging airway space.