Gravina Marco Abdo, Canavarro Cristiane, Elias Carlos Nelson, das Graças Afonso Miranda Chaves Maria, Brunharo Ione Helena Vieira Portella, Quintão Cátia Cardoso Abdo
Dental Press J Orthod. 2014 Jan-Feb;19(1):69-76. doi: 10.1590/2176-9451.19.1.069-076.oar.
This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel/Titanium (NiTi) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27ºC and 35ºC, Ormco) after traction test.
The analyses were performed in a scanning electronic microscope (JEOL, model JSM-5800 LV) with EDS system of microanalysis (energy dispersive spectroscopy).
The results showed that NiTi wires presented Ni and Ti as the main elements of the alloy with minimum differences in their composition. The CuNiTi wires, however, presented Ni and Ti with a significant percentage of copper (Cu). As for surface morphology, the wires that presented the lowest wire-surface roughness were the superelastic ones by Masel and Morelli, while those that presented the greatest wire-surface roughness were the CuNiTi 27ºC and 35ºC by Ormco, due to the presence of microcavity formed as a result of pulling out some particles, possibly of NiTi4. The fracture surfaces presented characteristics of ductile fracture, with presence of microcavities. The superelastic wires by GAC and the CuNiTi 27ºC and the heat-activated ones by Unitek presented the smallest microcavities and the lowest wire-surface roughness with regard to fracture, while the CuNiTi 35ºC wires presented inadequate wire-surface roughness in the fracture region.
CuNiTi 35ºC wires did not present better morphologic characteristics in comparison to the other wires with regard to surfaces and fracture region.
本研究旨在比较八种类型的镍钛（NiTi）传统丝材、超弹性丝材和热激活丝材（GAC、TP、奥美科、马塞尔、莫雷利和优尼康）在拉伸试验后，其断裂区域的定性化学成分和表面形态与添加铜（CuNiTi 27ºC和35ºC，奥美科）的丝材之间的差异。
分析在配备有能谱分析（能量色散光谱）的扫描电子显微镜（日本电子，型号JSM - 5800 LV）中进行。
结果表明，NiTi丝材呈现出Ni和Ti作为合金的主要元素，其成分差异最小。然而，CuNiTi丝材中，Ni和Ti伴随着显著比例的铜（Cu）。至于表面形态，表面粗糙度最低的丝材是马塞尔和莫雷利的超弹性丝材，而表面粗糙度最大的是奥美科的CuNiTi 27ºC和35ºC丝材，这是由于拔出一些可能是NiTi4的颗粒而形成微腔所致。断裂表面呈现韧性断裂特征，存在微腔。GAC的超弹性丝材、CuNiTi 27ºC丝材以及优尼康的热激活丝材在断裂方面呈现出最小的微腔和最低的表面粗糙度，而CuNiTi 35ºC丝材在断裂区域的表面粗糙度不合格。
与其他丝材相比，CuNiTi 35ºC丝材在表面和断裂区域方面未呈现出更好的形态特征。
