Wood was probably the first bioimplant, a sturdy, inert, and readily available material in the older days. But as mankind aged newer materials were discovered, and often created, that were indeed superior. The search for a exceptional implant alloy is one which has laboratories researching and testing different types of alloys for the best combination of strength, durability, corrosion resistance, and other important traits these alloys must possess.

The first implant metal to be discussed is stainless steel. The one most common stainless steel in use is 316L, grade 2. This particular alloy is mostly iron, chromium, and nickel, though it also contains nitrogen, magnesium, molybdenum, phosphorous, silicon, and sulfur. Most implant quality 316L has at least 62.5% iron, 17.6% chromium, and 14.5% nickel. The implan

t quality 316L has improved corrosion resistance, structure, and ductility over the commercial quality form of the alloy. An important property of the stainless steel alloy is its high chromium content which fights corrosion by forming an surface oxide. The nickel is added to insure "no delta ferrite", or to combat the impact the chromium, molybdenum, and silicon have in forming ferrite. "No delta ferrite" is a condition where there is no metallic resonance, allowing for the implant to still be safe even when the patient is undergoing an MRI. There is a drawback to the use of nickel in the implant, which in turn means there is a drawback to the implant itself. Somewhere in between 3% and 5% of the population is allergic to nickel. "Nickel causes inflammation and discoloration of tissue, retards reparative growth, produces excessive scars and erosion of bone"(2, pg.8) Physician's are instructed to ask the patient if they know of any allergies before they place the implant within a patient.

5) Ratner, Buddy D., Hoffman, Allan S., Schoen, Fredrick J., Lemons, Jack E. BioMaterials Science

Man has made tracks into helping the injured, the elderly, the unfortunate. Biomaterials are the tools leading the way in the battle to make life longer, healthier, and more complete for many individuals. As documented in this paper each biomaterial has strengths, as well as its weaknesses. So which is the most useful? That is the beauty of the situation as it exists today, no one material is the "one", each is suited for different circumstances. The pursuit to discover or engeneer the perfect alloy for all situations continues.

c. 1996 Academic Press San Diego, California

Some common words found in the essay are:
Introduction Wood, F136 Ti-6Al-4V, F90 F562, Science Publishers, F562 MP, Metals Abstract, Diego California, Inc York, Synthes USA, Tungsten Nickel, cobalt-based alloys, stainless steel, material found, implant alloys, implant quality 316l, implant quality, quality 316l, strengths f75, relevant material, surface oxide, nickel implant, relevant material found,
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Approximate Pages = 5 (250 words per page double spaced)