Deformation of nickel-titanium closed coil springs: an in vitro study

Camilla Ivini Viana VIEIRA, José Maurício dos Santos Nunes REIS, Luiz Geraldo VAZ, Lídia Parsekian MARTINS, Renato Parsekian MARTINS

Objective: The aim of this paper was to determine the amount of deformation in four commercial brands of nickeltitanium closed springs. Methods: A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, at 37 °C. Deactivation data were plotted and deformation was found graphically. The values were compared by analysis of variance and Tukey’s post-hoc test. Results: Springs manufactured by Morelli had the same amount of deformation when they were activated up to 700% of Y activation; springs by Orthometric had the same amount of deformation up to 600-700% of Y; springs by Ormco had the same amount of deformation up to 700-800% of Y; and finally, the majority of springs by GAC had similar deformation up to 800%-1000% of activation. All springs tested could be activated up to 700% without rupture. Conclusions: Most subgroups were similarly deformed up to 700% of activation, without rupture of springs. Subgroups 4B, 4C, 4D and 4E showed the same amount of deformation up to 1000% of activation without any rupture at all.

Keywords: NiTi. Deformation. Biomechanics.

How to cite: Vieira CIV, Reis JMSN, Vaz LG, Martins LP, Martins RP. Deformation of nickel-titanium closed coil springs: an in vitro study. Dental Press J Orthod. 2017 Jan-Feb;22(1):38-46. DOI: http://dx.doi.org/10.1590/2177-6709.22.1.038-046.oar

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