Upper Airway Changes In Patients With Skeletal Class Ⅲ Maxillary Retrognathia After Rapid Maxillary Expansion And Protraction:A Meta-analysis

Obstructive sleep apnea and hypopnea syndromes(OSAHS)is a common disease in children and adolescents,it is mainly caused by upper airway stenosis,which is caused by hypertrophy of adenoidal and tonsil.The conventional treatment is resection it.However,some OSAHS patients have no abnormalities in adenoids or tonsils.In recent years,some scholars have proposed that the craniofacial orthopedic treatment,especially maxillary expansion or sagittal growth stimulation,which can effectively reduce the risk that children whose adenoids or tonsils is normal,suffer the OSAHS.At present,rapid maxillary expansion(RME)combined with anterior traction(Facemask,FM)has been widely used in adolescent patients with lateral maxillary and sagittal hypoplasia,and the effect is significant.However,there is no consensus on the effect of RME+FM on upper airway volume and sagittal diameter in patients.Some results show that RME+FM improves the upper airway volume and sagittal diameter,but some studies show no significant change.The purpose of this study isto comprehensively collect existing clinical data,by the method of meta-analysis to evaluate the upper airway changes in patients with skeletal class Ⅲ maxillary retrognathia after rapid maxillary expansion and protraction.Thus,the best evidence-based evidence can be obtained to provide reference for clinical treatment.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 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 the 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<.05)increased significantly.However,no statistically significant differences in oropharyngeal volume(P >.05)and hypopharyneal volume(P >.05)existed.The nasopharyngeal airway dimensions had increased significantly with the following measurements: PNS-ad1(P<.05)、PNS-ad2(P<.05).However,no statistically significant differences in lower pharynx dimension existed with the following measurements: MPS(P>.05)、IPS(P>.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.