title: [Clinical study of extraction treatment of Class II division I malocclusion with Empower self-ligating brackets].
abstract: OBJECTIVE
  To evaluate and compare the treatment efficiency of Empower interactive self-ligating brackets and traditional brackets in Class II division I extraction patients.
  
  
  METHODS
  Forty patients with Class II division I malocclusion were randomly divided into 2 groups. Twenty patients received Empower self-ligating technique (group A) and the other 20 patients received MBT technique (group B). Four first premolars were extracted and without any other anchorage devices added in both groups. The duration of treatment, the number of visits and chair-side time were recorded. Cephalometric analysis was performed before and after treatment. The data was analyzed with SPSS 13.0 software package for paired t test.
  
  
  RESULTS
  Treatment time and number of visits in group A were more than in group B, but there was no significant difference between the 2 groups. Chair-side time in group A reduced 151.15s on average compared with group B. Significant changes were observed in both groups after treatment. Upper and lower anterior teeth retracted and convex profile improved.U1-SN, U1-NA, L1-MP, L1-NB, UI-PTV, LI-PTV, UL-EP, LL-EP decreased. Significant differences were found in UM-PTV between the 2 groups(P<0.05).
  
  
  CONCLUSIONS
  Compared with traditional brackets, Empower self-ligating brackets can save chair-side time, control anterior teeth torque and posterior teeth anchorage effectively, but can not reduce the treatment time or number of visits. Supported by Youth Research Project of Shanghai Municipal Health Bureau(2010Y155).
authors.affiliation: Department of Dentistry, Fengcheng Hospital, Shanghai. loveronion@sina.com
authors.forename: Xi-hua
authors.initials: XH
authors.lastname: Chen
authors.forename: Yong-mei
authors.initials: YM
authors.lastname: Hua
authors.forename: Xing-qian
authors.initials: XQ
authors.lastname: Xie
authors.forename: Xiao-jia
authors.initials: XJ
authors.lastname: Yu
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Li-ming
authors.initials: LM
authors.lastname: Liu
mesh_terms: D001641:Bicuspid; D002508:Cephalometry; D006801:Humans; D008310:Malocclusion; D016910:Orthodontic Brackets