What is a Cobalt Chrome Denture? Jamie the Dentist is the owner of Frendo Dental laboratory.
There is a metal called CoCr that is made of cobalt and chromium.Gas turbines, dental implants, and orthopedic implants are some of the things that usecobalt-chrome.[2]
The first Co-Cr alloy was discovered in the early 20th century.Many other elements were discovered in the alloy.Haynes reported that his alloy was able to resist oxidation and corrosive fumes and had no visible sign of tarnish when it was boiled with nitric acid.Under the name Stellite, Co-Cr alloy has been used in various fields where high wear-resistance was needed.
As its application was found, Co-Cr received more attention.The first Co-Cr heart valve was implanted in 1960 and lasted over 30 years, showing its high wear-resistance.Due to excellent resistant properties, biocompatibility, high melting points, and incredible strength, Co-Cr alloy is used for the manufacture of many artificial joints.[5]
The common Co-Cr alloy production requires the removal of the two metals from the oxide ores.The ores need to go through the reduction process to get pure metals.Pure cobalt can be achieved through many different methods depending on the characteristics of the specific mine.Pure metals are fused together under vacuum.Due to the chemical reactivity of metals at high temperature, the process requires vacuum conditions or inert atmosphere.A fine powder of the Co-Cr-Mo alloy is created when molten metals are ejected through a small nozzle and immediately cooled.[4]
It is very difficult to synthesise Co-Cr alloy through this method.In 2010, scientists at the University of Cambridge used a novel reduction technique called the FFC Cambridge Process to produce the alloy.[5]
The formation of a protective passive film made of mostly Cr2O3 and minor amounts of cobalt and other metal oxides on the surface is what gives Co-Cr a high resistance to corrosion.Co-Cr alloys are well known for their biocompatibility.The film interacts with the environment.Good mechanical properties that are similar to stainless steel are a result of a multiphase structure and precipitation of carbides.The strength of the Co-Cr alloy depends on how hard it is.As they are heat-treated, fatigue strength increases dramatically.The low ductility of Co-Cr can cause component fracturing.Hip replacements use the alloys and this is a concern.In order to overcome the low ductility, nickel, carbon, and/or nitrogen are added.The phase of Co-Cr has better mechanical properties than other phases.[2]
Several Co-Cr alloys are used in various fields.There are many Co-Cr-Mo alloy with similar composition but slightly different production processes.[4]
Different structures can be seen in Co-Cr alloys depending on the percent composition and temperature.The phase tends to be brittle and subject to a break.The FCC crystal structure is found in the phase, and it shows improved strength and ductility.FCC crystal structure is found in many types of alloys.The phase Co-Cr alloy has a crystal structure which can be seen at high pressures.[2]
Artificial joints include knee and hip joints due to their high wear-resistance and biocompatibility.When implanted, Co-Cr alloys tend to be resistant to rust, which reduces the chance of injury to the surrounding tissues.Excellent biocompatibility with blood and soft tissues is demonstrated by the use of Co-Cr alloy in the manufacture of surgical implants.The alloy composition used in orthopedic implants is mainly cobalt, with 27 to 30% chromium, 5 to 7%Molybdenum, and upper limits on other important elements such as less than 1% each of manganese and Silicon.[2]