title: Comparison of root resorption between self-ligating and conventional preadjusted brackets using cone beam computed tomography.
abstract: OBJECTIVE
  To compare the magnitude of external apical root resorption (EARR) of incisors in patients undergoing the initial phase of orthodontic treatment with two sets of brackets.
  
  
  METHODS
  According to the results of the power analysis for sample size calculation, 19 Angle Class I patients (anterior crowding: 3 to 5 mm; mean age: 20.6 years) were included in the study and randomly divided into two groups: group I (n  =  11, self-ligating brackets) and group II (n  =  8, conventional preadjusted brackets). The degree of EARR was detected in 152 upper and lower incisors by using cone-beam computed tomography (CBCT) scans and a three-dimensional program (Dolphin 11.5, Dolphin Imaging & Management Solutions, Chatsworth, Calif) with 25% level of sensitivity. The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were analyzed by nonpaired and paired t-test, respectively, with 5% significance level.
  
  
  RESULTS
  Significant differences were found for both groups between T1 and T2. However, no differences in the degree of EARR were detected between the groups studied.
  
  
  CONCLUSIONS
  Although EARR has occurred in all teeth evaluated, the bracket design (self-ligating or conventional) did not demonstrate any influence on the results observed.
authors.affiliation: Department of Orthodontics, University of North Paraná, Londrina, Paraná, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Leite
authors.forename: Ana Claudia
authors.initials: AC
authors.lastname: Conti
authors.forename: Ricardo
authors.initials: R
authors.lastname: Navarro
authors.forename: Marcio
authors.initials: M
authors.lastname: Almeida
authors.forename: Paula
authors.initials: P
authors.lastname: Oltramari-Navarro
authors.forename: Renato
authors.initials: R
authors.lastname: Almeida
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000000981:diagnostic imaging / Q000628:therapy*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets / Q000009:adverse effects*; D009971:Orthodontics, Corrective / Q000379:methods*; D011446:Prospective Studies; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology*