Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: Stress-strain tests
Marco Abdo GRAVINA, Ione Helena Vieira Portella BRUNHARO, Cristiane CANAVARRO, Carlos Nelson ELIAS, Cátia Cardoso Abdo QUINTÃO
Objective: This research aimed to compare, through traction tests, eight types of superelastic and heat-activated NiTi archwires, by six trade companies (GAC, TP, Ormco, Masel, Morelli and Unitek) to those with addition of copper (CuNiTi 27°C and 35°C, Ormco). Methods: The tests were performed in an EMIC mechanical testing machine, model DL10000, capacity of 10 tons, at the Military Institute of Engineering (IME). Results: The results showed that, generally, heat-activated NiTi archwires presented slighter deactivation loadings in relation to superelastic. Among the archwires that presented deactivation loadings biologically more adequate are the heat-activated by GAC and by Unitek. Among the superelastic NiTi, the CuNiTi 27°C by Ormco were the ones that presented slighter deactivation loadings, being statistically (ANOVA) similar, to the ones presented by the heatactivated NiTi archwires by Unitek. When compared the CuNiTi 27°C and 35°C archwires, it was observed that the 27°C presented deactivation forces of, nearly, ⅓ of the presented by the 35°C. Conclusion: It was concluded that the CuNiTi 35°C archwires presented deactivation loadings biologically less favorable in relation to the other heat-activated NiTi archwires, associated to lower percentage of deformation, on the constant baselines of deactivation, showing less adequate mechanical behavior, under traction, in relation to the other archwires.
Keywords: Orthodontic archwires. Dental movement. Copper. Nickel. Titanium. Physical properties.
How to cite: Gravina MA, Brunharo IHVP, Canavarro C, Elias CN, Quintão CCA. Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: Stress-strain tests. Dental Press J Orthod. 2013 July-Aug;18(4):35-42.
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