Cobalt chromium alloy was first used as implant material. Later, in order to solve the allergy problem of nickel containing metals, Europe and America developed cobalt chromium alloy specially used for porcelain repair. It will not cause alloy discoloration in the mouth of patients. Cobalt chromium alloy was first used in transplant medicine and used for hip joint, which is also a sign of its biocompatibility and has been used up to now.
As early as 1929, it was used in dentistry and was initially used in the repair of removable partial dentures. Cobalt chromium alloy: it is mainly developed for the toxicity of Ni and beryllium. Its cobalt content is higher than that of nickel based alloy, generally 25%. There are also elements such as Cu, W, Nb, Si, Ru, Al and mo. Because of its high cobalt content, its corrosion resistance is better than that of nickel based alloy, and the metal porcelain bond is good. Because it contains more chromium, its melting point is high, and there is a certain reaction between the alloy and the embedded material.
The cobalt chromium alloy used for porcelain teeth has an elastic modulus of 213745mpa and a hardness of 335 Vickers. Higher elastic coefficient, high comfort, no alloy discoloration in the patient's mouth. The difference between the cobalt chromium alloy used for porcelain fused to metal teeth and the cobalt chromium alloy used for partial denture support is the difference in the carbon content of the alloy. Generally, the former contains little or no carbon.
