The effect of rapid maxillary expansion and maxillary protraction treatment on the airway dimension in skeletal class III malocclusion patients

Objective To study airway changes in the correction of skeletal class III malocclusion by the treatment of rapid maxillary expansion(RME)and maxillary protraction.Methods Twenty subjects(9 males and 11 females,mean age of 10.5 years) were diagnosed by cephalometric analysis as skeletal Class III malocclusions with maxillary retrognathism.All subjects were taken treatment of rapid maxillary expansion and maxillary protraction.Cephalometric radiographs were taken before treatment(T0),after RME(T1)and after maxillary protraction(T2).Results After RME,only the length of soft palate became shorter for 1.02 ±0.92mm(P0.05).After maxillary protraction,the dimensions of PNS-R、UPW-PNS、SPP-SPPW increased significantly for 2.13 ±0.87mm、2.18 ±1.32mm、1.41 ±0.78mm(P0.05)and PAS、V-LPW decreased significantly for 1.56±1.32 mm、0.99±0.35mm(P0.05).Conclusion In young individuals with skeletal Class Ⅲ malocclusion with the treatment of rapid maxillary expansion and maxillary protraction,the dimensions of upper air way became wider and lower air way became narrower.However,all of them are normal.