title: Tooth angulation and dental arch perimeter-the effect of orthodontic bracket prescription.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of upper incisors and canine angulations introduced by different bracket prescriptions on dental arch perimeter.
  
  
  METHODS
  Cone beam computerized tomography scans collected using I-Cat (Imaging Sciences International, Hatfield, PA, USA) were selected conveniently from a database of routine exams of a clinical radiology center. Crown and radicular measurements of upper incisors and canines were made and exported to the Autocad 2011 software to create a virtual dental model. The virtual teeth were positioned with an angulation of zero; thereafter, a reference value for the perimeter of the arch was measured. Furthermore, teeth angulations were applied according to the standards of the Edgewise bracket system and the Straight-wire systems: MBT, Capelozza, Andrews, and Roth. The largest linear distances for tooth crown (anterior arch perimeter) and root (radicular distance) were obtained for each bracket prescription.
  
  
  RESULTS
  The anterior perimeter for well-aligned incisors and canines without angulation was used as reference (crown: 47.34mm; root: 39.13mm). An increase in the arch perimeter was obtained for all bracket prescriptions evaluated, which ranged from 0.28 and 3.19mm in the Edgewise technique, for the crown and root measurements, respectively, to 1.09 and 11.28mm for the Roth prescription.
  
  
  CONCLUSIONS
  Bracket prescriptions with greater angulation led to an increased use of space within the dental arch, mainly in the radicular region. The consequence of this radicular angular displacement will need to be further investigated.
authors.affiliation: *Department of Orthodontics, Federal University of Para and.
authors.forename: Luana F
authors.initials: LF
authors.lastname: Pontes
authors.affiliation: *Department of Orthodontics, Federal University of Para and.
authors.forename: Rodolpho L
authors.initials: RL
authors.lastname: Cecim
authors.affiliation: **Brazilian Association of Dentistry, Belem, Para, Brazil.
authors.forename: Sissy M
authors.initials: SM
authors.lastname: Machado
authors.affiliation: *Department of Orthodontics, Federal University of Para and davidnormando@hotmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Normando
mesh_terms: D017076:Computer-Aided Design; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003481:Cuspid / Q000473:pathology*; D003724:Dental Arch / Q000473:pathology*; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology*; D008297:Male; D008437:Maxilla / Q000473:pathology*; D003765:Models, Dental; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D012399:Rotation; D019228:Tooth Crown / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation; D014092:Tooth Root / Q000473:pathology; D014584:User-Computer Interface; D055815:Young Adult