title: Deflection Evaluation of Thermoactivated Nickel-Titanium Archwires after Heat Treatment on their Distal Ends.
abstract: This study evaluated in vitro the mechanical changes of 0.018" (0.45 mm) and 0.016 × 0.022" (0.40 × 0.55 mm) thermoactivated nickel-titanium archwires subjected to heat treatment on their distal ends.
  
  
  
  Ten archwires in diameters 0.018" and 0.016 × 0.022" by different manufacturers Ormco, Morelli, Orthometric and Unitek were tested. Each tested archwire had an experimental side, submitted to heat treatment, and an annealing-free control. Tests for load/deflection were performed using a universal testing machine, with temperature control in the austenitic transformation phase through tempe rature-controlled chamber. The variables showed normal distribution (Kolmogorov-Smirnov), the t-student test was applied in order to observe the difference between the experi mental and control groups. Statistical significance was set at p < 0.05.
  
  
  
  There were no statistically significant differences between the groups.
  
  
  
  Heat treatment carried out in the region corresponding to the first molar distal region on thermoactivated nickel-titanium archwires did not influence the load/deflection values in adjacent portion.
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Fausto Silva
authors.initials: FS
authors.lastname: Bramante
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Francisco Machado da
authors.initials: FM
authors.lastname: Fonseca Junior
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Célia Regina Maio
authors.initials: CR
authors.lastname: Pinzan-Vercelino
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Júlio de Araújo
authors.initials: Jde A
authors.lastname: Gurgel
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Rudys Rodolfo de Jesus
authors.initials: RR
authors.lastname: Tavarez
authors.affiliation: Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Brazil.
authors.forename: Etevaldo Matos Maia
authors.initials: EM
authors.lastname: Filho
authors.affiliation: Department of Post-Graduate Program in Integrated Dental Sciences, University of Cuiabá, Cuiabá, Brazil.
authors.forename: Mateus Rodrigues
authors.initials: MR
authors.lastname: Tonetto
authors.affiliation: Department of Post-Graduate Program in Integrated Dental Sciences, University of Cuiabá, Cuiabá, Brazil.
authors.forename: Alvaro Henrique
authors.initials: AH
authors.lastname: Borges
authors.affiliation: Professor, Department of Post-Graduate Program in Dentistry, CEUMA University, Sao Luis, Maranhão, Rua Josue Montello, n 01, Renascença, São Luis, Maranhão-84035-210, Brazil, e-mail: mbandeca@gmail.com.
authors.forename: Matheus Coelho
authors.initials: MC
authors.lastname: Bandéca
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D004548:Elasticity; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D044367:Phase Transition; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; C093826:Austenite; D009532:Nickel; D014025:Titanium
keywords: Orthodontic archwires; Heat treatment; Mechanical proprieties.