Power Arm在隐形矫治器联合微种植钉整体内收上前牙中的作用

目的 探讨Power Arm在无托槽隐形矫治器(clear aligner,CA)联合微种植体支抗(micro-implant anchorage,MIA)整体内收上前牙中的作用.方法 建立CA联合MIA整体内收上前牙三维有限元模型,在尖牙或尖牙所对应矫治器上加入高6 mm的Power Arm,分析矫治器施力+尖牙15...

The Role of Power Arm by Combined Use of Clear Aligner and Miniscrew in En-Masse Retraction of Maxillary Anterior Teeth

Objective To investigate the role of Power Arm in en-masse retraction of maxillary anterior teeth using clear aligner( CA) and micro-implant anchorage( MIA). Methods The three-dimensional( 3 D) model of maxillary anterior teeth by combined use of CA and MIA was established,and the 6 mm-height Power Arm,was attached to the canine or appliance. The initial displacement and the maximum von Mises stress of periodontal ligament under three loading conditions were analyzed,namely the force was loaded by CA+150 g retraction force at canine,CA+150 g retraction force on Power Arm at appliance,CA + 150 g retraction force on Power Arm at canine. Results In sagittal direction,the crown and root displacement difference of maxillary central incisor was129,129, 133 μm,respectively. The crown displacement of the maxillary first molar was-23. 3,-23. 5,-26. 8 μm,respectively. The maximum von Mises stress of periodontal ligament in central incisor was 48. 4,72. 6,40. 0 kPa,respectively,and that of the first molar was 5. 3,10. 5,5. 8 kPa,respectively. Conclusions It can not be testified that retraction of the 6 mm-height Power Arm at canine or appliance with 5 mm-height mini-screw has more advantages than retraction of the canine directly for more favorably controlling the torque of incisors,saving anchorage of posterior teeth and decreasing von Mises stress of the periodontal ligament.