The Efficiency Of Aided Maxillary Expansion With Different Devices

Objective:The aims of this study were to evaluate the efficacy of the two common devices,midpalatal suture split and temporary anchorage device(TAD)assisted maxillary expansion with cone-beam computed tomography(CBCT)in adult patients and to provide some reference and help for the design of clinical orthodontic program.Methods:The sample consists of 16 patients who diagnosed with Maxillary transverse deficiency(MTD)by cone-beam computed tomography(CBCT)(8 males and 8 females,mean age is 24 years old).The diagnose standard is MxMx<62mm and/or MnMn-MxMx?6mm,and the midpalatal suture is in stage D or E.The patients are randomly divided into group A and B.Group A contains 9 patients(5 females and 4 males),they used Shen's Cast Screw Expansioner(SCSE),and underwent Midpalatal Suture Split(MSS).Group B contains 7 patients(3 females and 4 males),they used TADs assisted maxillary expansioner.Both groups underwent 6-8mm maxillary expansion.The Expansioners were made by a same company,and the only difference is that Group B had 4 circles in the 4 corners of the device as the template to insert the miniscrews into the palatal.CBCT data were acquired before and 3 months after maxillary expansion,then the data were imported into Dolphin software to do 3D reconstruction,measurement and analysis.The contents of the measurement include:upper airway,maxilla and surrounding bone sutures and maxillary dentition.The data must be checked by Consistency test with inter-rater reliability and intra-rater reliability to ensure the reliability.Result:(1)Both groups the width between maxillary molars increased significantly(P<0.05).And the crown buccal torque of upper canines increased after treatment(P<0.05).The crown buccal torque of upper first molars increased significantly(P<0.05),but there was no significant difference in group B.(2)The width of Maxilla base,maxilla and surrounding bone sutures increased significantly(P<0.05).Compared with group A,group B had more increment in width between bilateral coracoid maxillary suture and pterygomaxillary suture(P<0.05).The ratio of increment of width of maxillary suture and width between upper first molars in Group B is 70%,which had higher efficacy than group A(50.8%).(3)In both groups,after maxillary expansion,the nasal cavity,anteroposterior diameter of nasopharynx,volume of upper airway and the minimum cross-sectional area of upper airway all increased significantly(P<0.05).Conclusion:(1)Maxillary expansion assisted with midpalatal suture split and TADs can not only open the midpalatal suture and surrounding bone sutures,but also increase the volume and minimu:m cross-sectional area of the upper airway.(2)Because the maxillary expansion assisted with TADshas better bony effect and less buccal inclination of molar crowns,it can be the first choice for the patients with maxillary transverse deficiency.