In 1980, Chinese and Japanese nickel-titanium alloy archwires were austenite-activated alloys: austenite was present in any state, and there was no martensite state caused by temperature in or out of the mouth. The martensite state could only be caused by stress and had superelasticity, but did n...

Special Properties of Nickel-Titanium Alloys include shape memory properties, superelasticity, sensitivity of temperature change in oral cavity, corrosion resistance, anti-toxicity, soft orthodontic force and good shock absorption characteristics.