title: External apical root resorption in patients treated with conventional and self-ligating brackets.
abstract: BACKGROUND
  Our aim was to comparatively investigate the amount of external apical root resorption (EARR) between conventional and passive self-ligating brackets.
  
  
  METHODS
  Ninety-six patients were selected from a pool of patients satisfying the following inclusion criteria: no evidence of resorption on the pretreatment panoramic radiographs; no contributing history of trauma; no dilacerations of lateral incisor roots, maxillary anodontia, and impacted canines; complete root formation at the start of treatment; intact and caries-free maxillary incisors; and no endodontically treated incisors. Patients received treatment with either a passive self-ligating bracket system or a conventional edgewise appliance, both with a 0.022-in slot. EARR of the maxillary incisors was evaluated on panoramic radiographs, taken before and after orthodontic treatment measured in millimeters. Distortion of measurements caused by panoramic radiographs was investigated by using a calibrated periodontal probe attached to the lateral incisor, and the extent of magnification was estimated to be 14%. Statistical comparisons of EARR between appliance type, age, sex, extraction treatment, and duration of treatment were investigated with univariate and multivariate regression modeling.
  
  
  RESULTS
  Overall, no difference was found in the amount of EARR between appliance systems. Age, sex, and extraction treatment were not reliable predictors of EARR, but a positive association between EARR and duration of treatment was observed.
  
  
  CONCLUSIONS
  No difference should be expected for root resorption between conventional and passive self-ligating brackets.
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, University of Athens, Athens, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
authors.forename: Maria
authors.initials: M
authors.lastname: Nasika
authors.forename: Argy
authors.initials: A
authors.lastname: Polychronopoulou
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008437:Maxilla; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets / Q000009:adverse effects* / Q000145:classification; D009969:Orthodontic Wires / Q000009:adverse effects; D009971:Orthodontics, Corrective / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D011859:Radiography; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology*; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D019227:Tooth Apex / Q000000981:diagnostic imaging / Q000473:pathology*; D014087:Tooth Movement Techniques / Q000009:adverse effects / Q000295:instrumentation