An overview of NiTi shape memory alloy: Corrosion resistance and antibacterial inhibition for dental application

Nowadays, Nickel-titanium nearly equiatomic is considered as one of the best biomaterials. The aim of the present work deals with the evolution of the electrochemical behavior of NiTi in simulated oral environment. The hardness, microstructures corrosion resistance and antibacterial performance of NiTi alloy were compared with pure titanium. The hardness of NiTi is twice the hardness of pure titanium. Electrochemical techniques were used to detect the corrosion resistance of both biomaterials in Hank's solution containing (-)-epigallocatechin gallate (EGCG) which used to simulate the oral environment. In the physiological solution selected for the present study, the impedance spectroscopy (EIS) results showed that EGCG sharply increase the corrosion resistance of NiTi from 129 k Omega cm(2) to 1.10 T Omega cm(2) while slowly increase the corrosion resistance of pure titanium from 9.4 k Omega cm(2) to 11.3 k Omega cm(2) during the duration time of immersion at 37 degrees C. The plate-counting method was used to evaluate the antibacterial performance against Staphylococcus aureus (ATCC 6538). Among the two specimens of biomaterials studied, the antibacterial performance results revealed that the NiTi alloy is better than the pure titanium. The morphology and chemical structure of NiTi and Ti samples were systematically investigated by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The study confirmed that the distinctive characteristics of the NiTi alloy back to its chemical composition with two phases from nickel and titanium. (C) 2013 Elsevier B. V. All rights reserved.