Force-deflection properties of initial orthodontic archwires.
OBJECTIVE
This in vitro study measured the force-deflection behavior of selected initial alignment archwires by conducting three-point bending tests under controlled conditions. The study tested four wire designs: multistranded stainless steel, conventional stainless steel, superelastic nickel-titanium, and thermoactivated nickel-titanium archwires.


METHODS
The wires (n = 15) were ligated into stainless steel brackets with steel ligatures. A testing machine recorded deactivations at 2.0 mm of deflection at 37 degrees C. Force-deflection measurements were recorded from only deactivation. Forces on deactivation were compared by one-way analysis of variance (ANOVA) and Tukey post-hoc tests.


RESULTS
Significant differences (P < .05) in deactivation forces were observed among the tested wires. The multistranded stainless steel wire had the lowest mean deactivation force (1.94 N), while the conventional stainless steel group had the highest value (4.70 N). The superelastic and thermoactivated Ni-Ti groups were similar to the multistranded wire (P > .05).


CONCLUSIONS
Both nickel-titanium and multistranded steel archwires tested are potentially adequate for use during the leveling and aligning phase of orthodontics.
Quintão
Cátia Cardoso Abdo
CC
Department of Orthodontics, State University of Rio de Janeiro, Rio de Janeiro, Brazil. cquintao@artnet.com.br
Cal-Neto
Julio Pedra e
JP
Menezes
Luciane M
LM
Elias
Carlos Nelson
CN
D003722:Dental Alloys / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D018583:Pliability; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry
D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium