title: Force levels of fiber-reinforced composites and orthodontic stainless steel wires: a 3-point bending test.
abstract: BACKGROUND
  The purpose of this study was to evaluate the force levels of 2 sizes (diameters, 0.6 and 1.2 mm) of fiber-reinforced composites (FRCs) (Ever Stick; Stick Teck Ltd, Turku, Finland) compared with orthodontic stainless steel wires (sections, 0.016, 0.018, 0.017 x 0.025, and 0.019 x 0.026 in) under the same testing conditions.
  
  
  METHODS
  The samples were divided into 12 groups, each consisting of 10 specimens. Each sample was evaluated with a 3-point bending test on a universal testing machine. The FRC groups were light-cured by hand with a halogen curing unit (Optilux 501; SDS Kerr, Danbury, Conn) for 40 seconds. Groups 1 through 6 were tested at 1-mm deflection, and groups 7 through 12 at 2-mm deflection.
  
  
  RESULTS
  The results of ANOVA indicated significant differences among the various groups (P = .000). The post-hoc test showed that the 2-mm deflection groups had significantly higher load values than the 1-mm deflection groups (P = .000). The highest force levels were recorded with the 1.2-mm FRCs, followed by the 0.019 x 0.026-in stainless steel wires. No significant differences were found between the 0.6-mm FRCs and the 0.017 x 0.025-in wires. The lowest load values were reported with the 0.016-in stainless steel wires.
  
  
  CONCLUSIONS
  The 1.2-mm FRCs showed higher load values than the other stainless steel wires and the FRCs, whereas no significant difference was found between the 0.6-mm FRCs and the 0.017 x 0.025-in stainless steel wires. Thus, FRCs can be considered a viable esthetic alternative to full-size stainless steel wires to rigidly join dental segments to form anchorage units or units for active tooth movement.
authors.affiliation: Department of Orthodontics, University of Pavia, Pavia, Italy. vcacciafesta@hotmail.com
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cacciafesta
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Sfondrini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lena
authors.forename: Andrea
authors.initials: A
authors.lastname: Scribante
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Lippo V
authors.initials: LV
authors.lastname: Lassila
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins; D003799:Dental Stress Analysis; D004548:Elasticity; D005898:Glass; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D018583:Pliability; D013193:Stainless Steel; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; C496140:everStick; C009753:fiberglass; D013193:Stainless Steel