title: Dimensional accuracy of ceramic self-ligating brackets and estimates of theoretical torsional play.
abstract: OBJECTIVE
  To ascertain the dimensional accuracies of some commonly used ceramic self-ligation brackets and the amount of torsional play in various bracket-archwire combinations.
  
  
  METHODS
  Four types of 0.022-inch slot ceramic self-ligating brackets (upper right central incisor), three types of 0.018-inch ceramic self-ligating brackets (upper right central incisor), and three types of rectangular archwires (0.016 × 0.022-inch beta-titanium [TMA] (Ormco, Orange, Calif), 0.016 × 0.022-inch stainless steel [SS] (Ortho Technology, Tampa, Fla), and 0.019 × 0.025-inch SS (Ortho Technology)) were measured using a stereomicroscope to determine slot widths and wire cross-sectional dimensions. The mean acquired dimensions of the brackets and wires were applied to an equation devised by Meling to estimate torsional play angle (γ).
  
  
  RESULTS
  In all bracket systems, the slot tops were significantly wider than the slot bases (P < .001), yielding a divergent slot profile. Clarity-SLs (3M Unitek, Monrovia, Calif) showed the greatest divergence among the 0.022-inch brackets, and Clippy-Cs (Tomy, Futaba, Fukushima, Japan) among the 0.018-inch brackets. The Damon Clear (Ormco) bracket had the smallest dimensional error (0.542%), whereas the 0.022-inch Empower Clear (American Orthodontics, Sheboygan, Wis) bracket had the largest (3.585%).
  
  
  CONCLUSIONS
  The largest amount of theoretical play is observed using the Empower Clear (American Orthodontics) 0.022-inch bracket combined with the 0.016 × 0.022-inch TMA wire (Ormco), whereas the least amount occurs using the 0.018 Clippy-C (Tomy) combined with 0.016 × 0.022-inch SS wire (Ortho Technology).
authors.affiliation: a  Student, Graduate School of Clinical Dentistry, Korea University, Seoul, Korea.
authors.forename: Youngran
authors.initials: Y
authors.lastname: Lee
authors.affiliation: b  Professor and Chair, Graduate School of Clinical Dentistry, Korea University, Seoul, Korea.
authors.forename: Dong-Yul
authors.initials: DY
authors.lastname: Lee
authors.affiliation: c  Clinical Instructor, Department of Orthodontics, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Yoon-Ji R
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D002516:Ceramics; D003430:Cross-Sectional Studies; D003722:Dental Alloys; D003799:Dental Stress Analysis; D017276:Friction; D006801:Humans; D007564:Japan; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel
chemical_list: D003722:Dental Alloys; D013193:Stainless Steel
keywords: Ceramic self-ligating brackets; Slot dimensions; Torsional play