Nitinol, an alloy of nickel and titanium, was first created by a US Naval Ordinance laboratory in the 1940's (hence the name - NIckel TItanium Naval Ordinance Lab). This special alloy is achieved by melting 55% nickel and 45% titanium. This new metal has the unique property of shape memory -- regardless of how the material is flexed and twisted , it will return to its original shape. This is an effect that occurs at specific temperatures. Nickel-titanium wires used for orthodontic procedures are pliable at room temperatures up to about 93°F. This allows the orthodontist the flexibility needed to manipulate the wire into place. At body temperature, they will return back to its original shape, producing a gentle 100 to 220 grams of force on the patient's teeth. Once the wire reverts to its original shape, it applies no further force and stays passively in the mouth.
Other Applications of Nitinol include:
Eye Glass Frames
Scoliosis Treatment Devices