title: The effect of water storage on the bending properties of esthetic, fiber-reinforced composite orthodontic archwires.
abstract: OBJECTIVE
  To study the effect of water storage on the bending properties of fiber-reinforced composite archwires and compare it to nickel-titanium (NiTi), stainless steel (SS), and beta-titanium archwires.
  
  
  METHODS
  Align A, B, and C and TorQ A and B composite wires from BioMers Products, 0.014-, 0.016, and 0.018-inch, and 0.019×0.025-inch NiTi, 0.016-inch SS, and 0.019×0.025-inch beta-titanium archwires were tested (n=10/type/size/condition). A 20-mm segment was cut from each end of the archwire; one end was then stored in water at 37°C for 30 days, while the other was stored dry. The segments were tested using three-point bending to a maximum deflection of 3.1 mm with force monitored during loading (activation) and unloading (deactivation). Statistical analysis was completed via two-way analysis of variance with wire and condition (dry and water-stored) as factors.
  
  
  RESULTS
  In terms of stiffness and force delivery during activation, in general: beta-titanium was >TorQ B>TorQ A>0.019×0.025-inch NiTi and 0.016-inch SS>Align C>0.018-inch NiTi>Align B>0.016-inch NiTi>Align A>0.014-inch NiTi. Water exposure was detrimental to the larger translucent wires (Align B and C, TorQ A and B) because they were more likely to craze during bending, resulting in decreased forces applied at a given deflection. Align A and the alloy wires were not significantly (P>.05) affected by water storage. Overall, the alloy wires possessed more consistent force values compared to the composite wires.
  
  
  CONCLUSIONS
  Environmental conditions are more likely to affect fiber-reinforced composite archwires compared to alloy wires.
authors.affiliation: a  Orthodontic Resident, Department of Developmental Sciences, Marquette University, Milwaukee, Wis.
authors.forename: Ju-Han
authors.initials: JH
authors.lastname: Chang
authors.forename: David W
authors.initials: DW
authors.lastname: Berzins
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Pruszynski
authors.forename: Richard W
authors.initials: RW
authors.lastname: Ballard
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D009969:Orthodontic Wires; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D003722:Dental Alloys; D003764:Dental Materials; C023988:beta titanium; D014867:Water; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium