title: Labio-lingual root control of lower anterior teeth and canines obtained by active and passive self-ligating brackets.
abstract: OBJECTIVE
  To investigate the torque capabilities of passive and active self-ligating (SL) brackets on mandibular incisors and canines using three-dimensional (3D) imaging analysis.
  
  
  METHODS
  Two types of SL bracket systems were analyzed: a passive and an active. Both brackets had a 0.022 × 0.028-inch slot size. Treatment protocol and wire sequences were followed as recommended by the manufacturers. Twenty-six patients were included in the passive group and 20 were included in the active group; all received pretreatment and posttreatment cone-beam computed tomography (CBCT) scanning. Based on the CBCT scans, a customized 3D analysis was developed to assess labiolingual inclination of the roots of mandibular canines and incisors with respect to the occlusal plane before and after treatment.
  
  
  RESULTS
  Following treatment, a statistically significant labiolingual proclination of the teeth was seen in both groups. Moreover, in both SL systems the roots exhibited a large variation in labiolingual inclination between adjacent teeth even after treatment.
  
  
  CONCLUSIONS
  A significant proclination was seen for the mandibular front teeth; the claimed third-order torque control of SL systems could not be demonstrated. Therefore, a considerable play between the wire and the brackets could be hypothesized, even more in relation to the passive than the active SL brackets.
authors.affiliation: Department of Orthodontics, School of Dentistry, Health, Aarhus University, Denmark. paolo.cattaneo@odontologi.au.dk
authors.forename: Paolo M
authors.initials: PM
authors.lastname: Cattaneo
authors.forename: Raaid A
authors.initials: RA
authors.lastname: Salih
authors.forename: Birte
authors.initials: B
authors.lastname: Melsen
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000473:pathology; D016022:Case-Control Studies; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003481:Cuspid / Q000473:pathology*; D003724:Dental Arch / Q000473:pathology; D003786:Dental Pulp Cavity / Q000473:pathology; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000473:pathology*; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008313:Malocclusion, Angle Class III / Q000628:therapy; D008334:Mandible / Q000473:pathology; D016910:Orthodontic Brackets / Q000145:classification*; D009969:Orthodontic Wires; D019227:Tooth Apex / Q000473:pathology; D019228:Tooth Crown / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation; D014092:Tooth Root / Q000473:pathology*; D019415:Torque