Clinical Research On Digital Design And Application Of Personalized Miniscrew Assisted Rapid Palatal Expander

ObjectiveTo investigatethe the digital design and manufacturing procedures of personalized miniscrew-assisted rapid palatal expander(pMARPE)and evaluate the skeletal and dentoalveolar changes of maxilla and displacement patterns of the zygomaticomaxillary complex(ZMC)after using this expander to treat adult patients with maxillary transverse deficiency(MTD)on sagittal and on coronal plane.MethodsPMARPE was fabricated for each patients using digital technology such as intraoral digital scanning,CAD/CAM,and 3D printing.Ten subjects aged from 18.00 to 27.08 years(3 males,7 females,average 21.56±3.00 years)with MTD were included and treated with pMARPE.Cone-beam computed tomography(CBCT)records of 10 subjects were taken before expansion,after expansion and after retention for three months.The maxillary width,molar inclination,buccal alveolar height,alveolar width and linear and angular parameters of ZMC were identified by dolphin Imaging software.These parameters were analyzed by paired t-test in SPSS 21.0 software.Results1.Skeletal changesThe screw was expanded average 6.81±1.35 mm after expansion.The widths of anterior and posterior midpalatal suture increased by 3.81±1.25 mm and 3.66±1.21 mm(P<0.05).The maxillary basal bone width of the first premolar and the first molar increased by 4.07±1.28 mm and 3.21±1.22 mm(P<0.05).There was no significant change in skeletal changes after retention for three months(P>0.05).2.Dentoalveolar changesThe widths of inter maxillary first premolar and first molar increased by 5.37±2.16 mm and 6.20±1.92 mm after expansion(P<0.05).The inclination of the first premolar on the left and right sides increased by 0.90±2.93°and 3.59±4.50°.The inclination of the first molar on the left and right sides increased by 4.66±2.26°and 5.67±3.93°(P<0.05).The buccal alveolar height and alveolar width of first premolar and first molar were slightly reduced and the difference was not statistically significant(P>0.05).After retention for three months,the inclination of the first premolar on the left and right sides decreased by 3.39±2.22°and 3.41±3.60°(P<0.05).The inclination of the first molar on the left and right sides increased by 3.73±4.44° and 0.73±3.57°(P>0.05).3.ZMC changesThe anterior intermaxillary distance,posterior interzygomatic distance and lower interzygomatic distance increased by 1.50±0.98 mm,1.21±0.75 mm and 2.70±1.52 mm after expansion.The frontozygomatic angle on the left and right sides increased by 1.26±0.99°and 2.23±1.75°(P<0.05).There was no significant difference in the changes of all parameters after retention for three months(P>0.05).Conclusions1.PMARPE produced in CAD/CAM procedures can be use an effective tool for expanding the maxilla of adult patients with MTD.2.PMARPE had significant impact on maxilla and slight side effects on molars.3.In the horizontal plane,the ZMC were displaced in a lateral direction with a rotation center,locating proximal portion of the zygomatic process of the temporal bone.In the coronal section,the ZMC tended to rotate outwards with a rotation center,locating frontozygomatic suture on coronal section.