title: Bracket slot and archwire dimensions: manufacturing precision and third order clearance.
abstract: OBJECTIVE
  To determine the accuracy of different manufacturer's dimensions of bracket slots and stainless steel archwires and compare these against the tolerance limits given by DIN 13971 and 13971-2. Further to calculate torque play and effective torque and to compare the results to nominal torque.
  
  
  METHODS
  A laboratory investigation.
  
  
  METHODS
  The Department of Orthodontics and Dentofacial Orthopedics at Medical University of Graz, Austria.
  
  
  METHODS
  Ten upper central incisor brackets (0·022 inch) from five different bracket systems were investigated. Bracket slot height was measured with leaf gauges. The height and width of 10 stainless steel archwires with dimensions either 0·019×0·022 or 0·020×0·025 inch were measured using a micrometer.
  
  
  RESULTS
  All measured bracket slot heights were within the upper and lower tolerance limits given by DIN 13971-2. Archwires showed measurements outside the upper and lower tolerance limits given by DIN 13971. The smallest effective torque loss (4·5°) resulted from the combination of the 0·022-inch SPEED System bracket with the 0·020×0·025-inch SPEED Wire small upper. The highest torque loss (11·7°) was found with the 0·022-inch Damon 2 bracket and the 0·019×0·025-inch ECO Charge 1 archwire.
  
  
  CONCLUSIONS
  The accuracy of the manufacturers dimension is not to be taken for granted. A perfect 'finishing' still requires correction bends put in by the orthodontist.
authors.affiliation: Medical University of Graz, School of Dentistry, Department of Orthodontics and Dentofacial Orthopedics, Auenbruggerplatz 12, 8036 Graz, Austria. astrid.joch@medunigraz.at
authors.forename: Astrid
authors.initials: A
authors.lastname: Joch
authors.forename: Margit
authors.initials: M
authors.lastname: Pichelmayer
authors.forename: Frank
authors.initials: F
authors.lastname: Weiland
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D003722:Dental Alloys; D007180:Incisor; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012015:Reference Standards; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D019415:Torque
chemical_list: D003722:Dental Alloys; D013193:Stainless Steel