title: Biomechanical characteristics of self-ligating brackets in a vertically displaced canine model: a finite element analysis.
abstract: OBJECTIVE
  The objective of this study was to compare the biomechanical characteristics between two types of self-ligating brackets and conventional metal brackets using finite element analysis of a vertically displaced canine model focusing on the desired force on the canine and undesirable forces on adjacent teeth.
  
  
  METHODS
  Three-dimensional finite element models of the maxillary dentition with 1-mm, 2-mm, and 3-mm vertically displaced canines were constructed. Two different self-ligating brackets (In-Ovation C and Smart clip) and a conventional metal bracket (Micro-arch) were modeled. After a 0.016-inch NiTi (0.40 mm, round) wire was engaged, the displacement of each tooth was calculated using x-, y-, and z-coordinates, and the tensile and compressive stresses were calculated.
  
  
  RESULTS
  The extrusion and maximal tensile stress of the canine differed little between the three brackets, but the intrusion and minimal compressive stress values of the adjacent teeth differed considerably and were highest in the Smart clip and least in the In-Ovation C. The extrusion and maximal tensile stress of the canine in the 3-mm displacement model was less than that in the 2-mm displacement model, and the intrusion and minimal compressive stress of the adjacent teeth increased with the degree of displacement.
  
  
  CONCLUSIONS
  Self-ligating brackets were not superior to conventional brackets in leveling a vertically displaced canine. A continuous arch wire may not be recommended for leveling of severely displaced canines whether using self-ligating or conventional brackets.
authors.affiliation: Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: S-J
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Private Clinic, Seoul, South Korea.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Kwon
authors.affiliation: Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: C-J
authors.initials: CJ
authors.lastname: Hwang
mesh_terms: D003722:Dental Alloys; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires
chemical_list: D003722:Dental Alloys
keywords: finite element analysis; self-ligating brackets; vertically displaced canine