title: A comparative experimental investigation of torque capabilities induced by conventional and active, passive self-ligating brackets.
abstract: BACKGROUND
  A proper selected bracket-archwire combination displays a determining factor in the efficacy of torque applied to a tooth at the final stages of an orthodontic treatment. The objective of the current study was to assess the torque capabilities of various bracket systems combined with diverse archwire materials and cross-sections.
  
  
  METHODS
  The study comprised of four different 0.018-inch slot orthodontic brackets: the passive and the active self-ligating 1. Swiss Nonligating Bracket (SNB) and 2. SPEED and the metallic and the plastic conventional ligating 3. Mini Mono and 4. Brilliant, respectively, and four different archwire types: stainless steel and Nitinol: 0.016×0.016 inch and 0.016×0.022 inch. A 20 degrees labial crown torque (+20 degrees) and then a 20 degrees palatal crown torque (-20 degrees) were applied gradually on the upper right central incisor. Maximum torquing moments and torque play were registered.
  
  
  RESULTS
  Highest torquing moments were expressed by combining SPEED® with 0.016×0.022 inch stainless steel archwire. Lowest moments, but highest torque loss were registered by inserting a 0.016×0.016 inch Nitinol archwire in conventional ligating brackets.
  
  
  CONCLUSIONS
  Active self-ligating system manifests the best torque effectiveness. An evident dependence of the torque expression is displayed both on the type of ligation and on the material of the archwire.
authors.affiliation: *Endowed Chair of Oral Technology, School of Dentistry, Rheinische Friedrich-Wilhelms University, Bonn, **Department of Orthodontics, School of Dentistry, University of Heidelberg, and eleni.katsikogianni@med.uni-heidelberg.de.
authors.forename: Eleni N
authors.initials: EN
authors.lastname: Katsikogianni
authors.affiliation: *Endowed Chair of Oral Technology, School of Dentistry, Rheinische Friedrich-Wilhelms University, Bonn.
authors.forename: Susanne
authors.initials: S
authors.lastname: Reimann
authors.affiliation: *Endowed Chair of Oral Technology, School of Dentistry, Rheinische Friedrich-Wilhelms University, Bonn.
authors.forename: Anna
authors.initials: A
authors.lastname: Weber
authors.affiliation: ***Orthodontist, Private Practice, Heimstetten, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Karp
authors.affiliation: *Endowed Chair of Oral Technology, School of Dentistry, Rheinische Friedrich-Wilhelms University, Bonn.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
mesh_terms: D000497:Alloys / Q000737:chemistry; D001577:Benzophenones; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis; D020724:Elastomers / Q000737:chemistry; D006801:Humans; D007180:Incisor / Q000473:pathology; D007659:Ketones / Q000737:chemistry; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets / Q000145:classification*; D009969:Orthodontic Wires; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers; D012117:Resins, Synthetic / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque
chemical_list: D000497:Alloys; D001577:Benzophenones; D003722:Dental Alloys; D003764:Dental Materials; D020724:Elastomers; D007659:Ketones; D011108:Polymers; D012117:Resins, Synthetic; D013193:Stainless Steel; C013616:nitinol; C063834:polyetheretherketone; D011092:Polyethylene Glycols; C010102:delrin