Artificial bone



For years the main source of bone for replacement purposes was cadavers (dead bodies). In fact, the Red Cross maintains a "bone bank" for just this purpose. Recently, physicians have experimented with using metals for bone replacement. Two alloys (mixtures of two or more metals)—titanium and cobalt chromium—have been frequently tested. Because any foreign substance in the body is subject to rejection, scientists are constantly trying to find more acceptable materials.

Specifically, scientists are looking for substances that more closely resemble real bone. Hydroxyapatite is a mineral that makes up about 65 percent of living bone. Attempts to bake natural hydroxyapatite powder into a hard bone substitute have often failed. The high processing temperature needed for baking causes the hydrogen-oxygen mixture to boil off, leaving researchers with a weak ceramic (a material like pottery or tile). Strengthening the ceramic with silica (a hard, glassy mineral) and other elements usually causes a high body rejection rate.

A chemist at the University of Texas named Richard J. Lagow developed a way the synthesize hydroxyapatite. His process created a strong and porous (full of small pores, or holes, through which material may pass) form similar to tooth enamel. When this material is introduced into the body, its porous nature allows blood vessels and cells to enter. The absoption process gradually breaks down the implant and creates pores into which natural bone can grow. In the late 1980s testing began of Lagow's discovery for dental and orthopedic use.



User Contributions:

Richard
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Oct 3, 2008 @ 12:12 pm
I am lookig to find out if this can be applide to dental work like sealing and, or when widdening the upper palat?
MARCO JANSZEN
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Aug 27, 2009 @ 11:23 pm
hello, my mother had a rare cancer in her shoulder about 20 years ago , she was accepted by UCLA , and they put an artificial titanium shoulder blade in place , she would otherwise have lost her arm , or her life , we are very greatfull with all the people that made this happen for her , however , since the last 4 years she has gotten an infection in her arm and her docter is saying that there is nothing he can do for her , it is what it is , she is in a lot of pain because of this , i just wish there was something we could do for her , she is only 69 years old and now lives in holland , any suggestions
hector
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Jan 4, 2010 @ 7:19 pm
if a bone is subject to cancer can it be replaced with the artificial bone like the one developed by Richard J. Lagow?
Ahmad
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Apr 17, 2012 @ 3:15 pm
There are two general kinds of bone graft tgfouraat (where they take the patient's own bone from elsewhere in their body) and allograft (where they take bone from a donor usually a cadaver). In tgfouraating, none of the processing you mention is needed, because the bone is the patient's own: the details you describe are for allografts.Surgeon's don't leave just the hydroxyapatite they leave "decellularised bone matrix". They remove the cells, leaving the hydroxyapatite and extracellular matrix proteins (in fact, often they remove the hydroxyapatite too).The hydroxyapatite *is* the mineral component, so osteocytes only need to mineralise the bone graft if the hydroxyapatite has been removed.> "How do the jaw bone cells make new bone?"That is just what bone cells do. There are two types of bone cell osteoblasts (which build bone) and osteoclasts (which destroy bone). These have a complex interaction, constantly building and destroying bone in balance. If there is not enough bone, then the osteoblasts upregulate their activity, while the osteoclasts turn themselves off.> "How do the cells know to make new bone?"They have receptors in their plasma membrane that can detect the amount and composition of the bone they are in, and they respond accordingly.> "Are the new bone cells the same as the existing bone cells or are they different?"They are the same, because they came from the patient, not the graft. The graft is "decellularised" to remove all the donor's cells. Otherwise it might be rejected by the host (it is the cells that carry the histocompatibility proteins).

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