The Comparision Of Clinical Efficacy Between Bracketless Invisible Appliance And Fixed Appliance In Maxillary Distalization

Objective:To compare the lateral cephalograms before and after distalization of maxillary molars in patients with Angle’s class Ⅱ division 1 malocclusion using bracketless invisible appliance and fixed appliance,and to compare the clinical efficacy of the two correction methods,so as to provide reference for the selection of clinical correction method.Methods:20 subjects were selected in each group.The experimental group was treated with Invisalign invisible appliance,while the control group with Damon Q self-locking bracket appliance.The lateral cephalograms before treatment(T0)and after molar distalization(T1)were collected from all the patients,and the data were measured using cephalometric imaging module.The measured data were analyzed with SPSS 21.0,the intra-group data were analyzed using the paired sample t-test,and the inter-group data were compared by the independent sample t-test.Results :1.The Experiment Group: maxillary first molar distalization: 3.17±0.67 mm,vertical depressing: 1.87±0.63mm;second premolar vertical depressing:0.88±0.29mm;central incisor vertical depressing: 1.43±0.41 mm,decrease in labially tilted angle: 0.73±0.23°,decrease in convexity: 0.74±0.22mm;MP-FH decrease: 1.21±0.43°.The difference is statistically significant.2.The Control Group: maxillary first molar distalization: 2.09±0.70mm;second premolar mesialization 0.78±0.32mm;central incisor mesialization1.16±0.23 mm,increase in labially tilted angle: 1.33±0.42°,increase in convexity: 1.00±0.21 mm.The difference is statistically significant.3.According to comparison between groups,the experiment group shows more significant effect in distalization of maxillary first molar,vertical depressing and decrease in MP-FH;the control group is more significant in mesialization of maxillary second premolar,mesialization of maxillary central incisor,and increase in labially tilted angle and convexity.Conclusions:1.Both orthodontic treatment modes can achieve effective molar distalization.But invisible appliance shows more significant and reliable results.2.In anchorage control,invisible appliance better than fixed appliance.3.In vertical control,invisible appliance perform better.4.Invisible appliance and fixed appliance are both a kind of appliance.No matter which one is used,appropriate anchorage methods are needed to achieve the desired effect.