Titanium

 
chemical elementTi, 22Ti
physicalMetal, high strength-to-weight-ratio.
chemicalOxidizes in air. Reacts with water and forms a passive oxide coating that protects the metal from further oxidation.
occurrenceNinth-most element in earth crust.
About 50 grades of titanium and his alloys known, 35 grades ASTM, commercially used are Grades 1 through 4. It comes with additional aluminum, vanadium, mangan, molybdenum, palladium, copper, zirconium dioxide, iron and tin.

Dental implants are often made of titanium grade 4 or 5 (also Ti6Al4V, Ti-6Al-4V or Ti 6-4). It contains beside titanium 6 % aluminum, 4 % vanadium, 0,25 % (maximum) iron and 0,2 % (maximum) oxygen. Titanium Grade 4 is stronger than pure titanium and has a 60% less thermal diffusivity. The smaller the implant, the more grade 5 is preferred.

propertiesNon-toxic, lightweight, corrosion resistant, biocompatible, long-lasting, non-ferromagnetic, strong.
applicationsDental implants, orthopedic implants, general surgery implants (plates, screws), neurosurgery, hearing aids, spinal fusion cages, pacemakers, replacements of many bones.
biocompatibilitySo far the most biocompatible metal. It works with a protective oxide film.
specialDifferent methods to increase the surface are used to improve the stability within bone.

Coating is possible. e.g. with HA.

adverse effectsNo allergic reaction known. Some intolerances have been reported.

Alternatives exist in ceramic or coated implants.