Clinical Study Of Distalization Of Maxillary Molars By Clearaligner And Pendulum Appliance In Patients With Low Angle

Objectives:To analyze the three-dimensional changes of the maxillary molars before and after the distal movement of the maxillary molars and the vertical changes of the patient’s bone surface by the combination of Dolphin Imaging and CBCT.To explore the clinical efficacy and vertical change of invisible and pendulum appliance distal movement,and provide reference for clinical diagnosis and treatmentMethods:Randomly selected 40 patients with Angle’s Ⅱ malocclusion who were treated in the Department of Orthodontics,the Attached Stomatology Hospital of KMMC during 2014.09-2016.12,were randomly selected 20 patients were treated with Clearaligner(group A)and another 20 patients were treated with pendulum appliance(group B)for distalization of maxillary molars.Were Collected patients CBCT result before and after treatment,The Dolphin Imaging measurement software was used to measure the three-dimensional changes of the molars and anterior teeth after the distal movement of the molars and the changes of the patient’s lower 1/3 and mandibular plane angles.Data were processed by SPSS20.0 softwareResults:1.before and after treatment of the pendulum appliance group,the average distance of the maxillary first molar(U6)crown was-2.55(-3.30,-1.10)mm(P<0.05),The average distance of tooth root movement was-1.40(-2.25,-0.60)mm(P<0.05),and the upper root first molar was 0.40(0.05,0.80)mm(P<0.05).The median movement of the maxillary second premolar(U5)was 0.85(0.05,1.95)mm(P<0.05),and the average proximal movement of the root was 0.75(0.30,1.25)mm(P<0.05).The maxillary central incisor(U1)was treated before and after the crown.The average lip tilt was 1.15(0.60,1.60)mm(P<0.05)and the average root movement of the root was 0.70(0.30,1.10)mm(P<0.05).2.before and after treatment,the maxillary first molar(U6)had a mean distal movement of-2.40(-3.03,-1.47)mm(P<0.05),the distal movement of the root was-1.82(-2.20,-0.94)mm(P<0.05),and the maxillary first molar was 0.30(-0.10,0.65)mm(P<0.05).The change of three-dimensional direction before and after treatment of premolar(US)was not obvious.The maxillary central incisor(UI)was extended vertically-0.55(-1.18,-0.20)mm(P<0.05).3.FMA、SN-MP、PP-MP、LFH(ANS-Me)(mxn)、(ANS-Me:N-Me)(%)were increased before and after treatment in the pendulum appliance group(P<0.05).The mandibular plane was rotated clockwise,and the patient’s face was three-thirds.One becomes higher.The change trend of the bracketless invisible appliance group is basically the same as that of the pendulum appliance group.However,SN-FOP is reduced;PP-FOP,L6-MP(LPDH)(mm)is slightly increased.But smaller than the pendulum appliance grouP(P<0.05)Conclusions:1.Both the invisible appliance and the pendulum appliance can effectively move the maxillary molars,and the invisible appliance can better move the molars in the whole distance.2.The bracketless invisible appliance is used to reduce the loss of anterior teeth when moving the molars in the far middle.3.The bracketless invisible appliance is better for vertical control than the pendulum appliance when it is used to move the molars in the far middle.