title: [Comparison of root resorption between self-ligating and conventional brackets using cone-beam CT].
abstract: OBJECTIVE
  To analyze the differences of root resorption between passive self-ligating and conventional brackets, and to determine the relationship between passive self-ligating brackets and root resorption.
  
  
  METHODS
  Fifty patients were randomly divided into 2 groups using passive self-ligating brackets or conventional straight wire brackets (0.022 system), respectively. Cone-beam CT was taken before and after treatment. The amount of external apical root resorption of maxillary incisors was measured on CBCT images. Student's t test was performed to analyze the differences of root apical resorption between the 2 groups with SPSS17.0 software package.
  
  
  RESULTS
  No significant difference(P> 0.05) in root resorption of maxillary incisors was found between passive self-ligating brackets and conventional brackets.
  
  
  CONCLUSIONS
  Passive self-ligating brackets and conventional brackets can cause root resorption, but the difference was not significant. Passive self-ligating brackets do not induce more root resorption.
authors.affiliation: Department of Orthodontics, Hangzhou Dental Hospital. Hangzhou 310005,Zhejiang Province，China. E-mail:liuyun0825@126.com.
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Hong-ming
authors.initials: HM
authors.lastname: Guo
mesh_terms: D054893:Cone-Beam Computed Tomography; D006801:Humans; D007180:Incisor; D008026:Ligation; D016910:Orthodontic Brackets; D012391:Root Resorption