Biocompatible metal commonly used for dental implants. It is an alloy of approximately 99 wt.% titanium and small amounts (from 0.18 to 0.40 wt.%) of oxygen with trace amounts (less than 0.25 wt.%) of iron, carbon, hydrogen, and nitrogen. Commercially pure titanium is classified in multiple grades. The amount of oxygen determines the grade of the alloy.