Four groups of arch wires (nickel titanium [NiTi], SS, Cu NiTi and ion implanted NiTi) with twelve samples were stored in artificial saliva with a pH 5.6-7.0 thermostated at (36.5°C) and tested at different intervals i.e., 7(th) day, 14(th) day, and 21(st) day. 
THERM