Abstract
•Evaluate the corrosion resistance of NiTi alloy by using electrochemical techniques.•Estimate the Antibacterial inhibition rate of NiTi alloy.•Assessment the mechanical properties of NiTi from the hardness measurements.•Comparsion the microstructures of cast NiTi with Ti, this indicate the role of Ni to change the behavior of alloy in oral environment.•Advise drinking green tea in small quantities in small quantities in the event of present NiTi alloy in the oral cavity.•Recommendation to use NiTi 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 129kΩcm2 to 1.10TΩcm2 while slowly increase the corrosion resistance of pure titanium from 9.4kΩcm2 to 11.3kΩcm2 during the duration time of immersion at 37°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.