Biocompatibility and Norms - Biomaterials - page 86

implantation site to another. Therefore, biocompatibility cannot
exclusively depend on the characteristics of the material and must be
defined according to the application to which the biomaterial is
intended;
- in the majority of cases, the material has to specifically respond
and interact with surrounding tissues rather than be inactive or passive
or inert;
- in a similar context, some particular applications require a
degradation of the material over time rather than staying infinitely
biodegradable biomaterials.
With the expanding experience in biomaterials science, the
definition has evolved to that proposed in 1987 by D. Williams
[WIL 87]: “Biocompatibility refers to the ability of a material to
perform with an appropriate host response in a specific application”.
This is an exact definition of biocompatibility's point of view
Nevertheless, biomaterials are not exclusive to the research domain
and many people use and abuse the word “biocompatibility” or the
adjective “biocompatible”. Sometimes, it does not match reality.
Why? Is biocompatibility possible for all implanted materials? What
is an appropriate host response?
4.3. Discussion on biocompatibility
Why can biomaterials not be dissociated from the notion of
biocompatibility? The reason is that when introduced in the body of a
human being, biomaterials inevitably lead to interactions with the
biological systems, the other name of which is “the host response”.
The host response (see below) is a very complex set of reactions.
For a long time, biomaterials were classified according to their
reactivity toward living systems. A biomaterial could be qualified as:
- bioinert: if its role was restricted to the replacement of one or
several functions of an organ, such as cardiac valves;