title: Deflection test evaluation of different lots of the same nickel-titanium wire commercial brand.
abstract: BACKGROUND
  The aim of this in vitro study was to compare the elastic properties of the load-deflection ratio of orthodontic wires of different lot numbers and the same commercial brand.
  
  
  METHODS
  A total of 40 nickel-titanium (NiTi) wire segments (Morelli Ortodontia™--Sorocaba, SP, Brazil), 0.016-in in diameter were used. Groups were sorted according to lot numbers (lots 1, 2, 3 and 4). 28-mm length segments from the straight portion (ends) of archwires were used. Deflection tests were performed in an EMIC universal testing machine with 5-N load cell at 1 mm/minute speed. Force at deactivation was recorded at 0.5, 1, 2 and 3 mm deflection. Analysis of variance (ANOVA) was used to compare differences between group means.
  
  
  RESULTS
  When comparing the force of groups at the same deflection (3, 2 and 1 mm), during deactivation, no statistical differences were found.
  
  
  CONCLUSIONS
  There are no changes in the elastic properties of different lots of the same commercial brand; thus, the use of different lots of the orthodontic wires used in this research does not compromise the final outcomes of the load-deflection ratio.
authors.affiliation: Universidade Ceuma, São Luís, Maranhão, Brazil.
authors.forename: Murilo Gaby
authors.initials: MG
authors.lastname: Neves
authors.affiliation: Universidade Ceuma, São Luís, Maranhão, Brazil.
authors.forename: Fabrício Viana Pereira
authors.initials: FV
authors.lastname: Lima
authors.affiliation: Universidade Ceuma, São Luís, Maranhão, Brazil.
authors.forename: Júlio de Araújo
authors.initials: Jde A
authors.lastname: Gurgel
authors.affiliation: Universidade Ceuma, São Luís, Maranhão, Brazil.
authors.forename: Célia Regina Maio
authors.initials: CR
authors.lastname: Pinzan-Vercelino
authors.affiliation: Universidade Ceuma, São Luís, Maranhão, Brazil.
authors.forename: Fernanda Soares
authors.initials: FS
authors.lastname: Rezende
authors.affiliation: School of Dentistry, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Gustavo Antônio Martins
authors.initials: GA
authors.lastname: Brandão
mesh_terms: D001938:Brazil; D003722:Dental Alloys; D003799:Dental Stress Analysis; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D009532:Nickel; D009969:Orthodontic Wires; D014025:Titanium
chemical_list: D003722:Dental Alloys; D009532:Nickel; D014025:Titanium