Artificial joints and artificial bone substitute materials should have the following basic properties: lightweight, high-strength materials, biocompatibility and corrosion resistance, and the reaction of the implanted tissue in the body will not cause material deterioration, repeated stress-induced fatigue, and small damage. The most important properties of metal implants are shape, processing and polishing. They must remain functional during their expected life and will not degrade under fatigue, wear, corrosion and impact loads.
Titanium and titanium alloys meet all the above requirements. Artificial joint materials such as denture powder, polypropylene, plexiglass have low strength, are easy to break, and have poor biocompatibility. Later, stainless steel was used, but the proportion of stainless steel was greater, about twice the proportion of human bones. Under the action of body fluids, the human body would corrode and fracture. Cobalt-chromium alloy is also an excellent artificial joint material, but unfortunately, cobalt and chromium are toxic to the human body. Titanium and titanium alloys are ideal artificial joint materials, which have the advantages of small proportions (similar to the proportion of human bones), high strength, good workability, and corrosion resistance. Titanium materials used for surgical transplantation mainly include pure titanium and ti-6al-4veli alloy. In recent years, Ti-6Al-7Nb and Ti-13nb1-13zr have good compatibility with the human body and have passed the ASTM standard.
Titanium is an artificial bone on which cells can regenerate and bones can grow. Titanium has a good affinity with human bones, epithelium and tissues. In order to improve the surface quality of the implant material connected with the human bone, applying a bioceramic layer to the rough implant surface is also an effective method. At present, titanium and titanium alloys have been widely used in artificial bone joints, artificial bones, joint bottom plates, fracture fixators, bone marrow nails, artificial heart valves, skulls, etc.
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