Functional biomaterials definition

Biomaterials are by definition materials that assume the functions of tissue in natural organs or organ parts. They must therefore imitate the properties of such tissue as well as possible. For example, a vascular prosthesis must exhibit a tension-expansion curve highly similar to that of a natural blood vessel, as well as a smooth inner surface which corresponds to the endothelial covering. In other words, a biomaterial must be made to act as much as possible like the natural tissue in Its biological environment - in the case of vascular prostheses in the environment of blood, tissue, and interstitial fluid -, it must withstand biodegradation and prove to be biocompatible (Table 1). 

According to the definition, biomaterials are nonliving materials designed to interact with the biological system while reinforcing or replacing human body functions under mechanical, biological, and chemical constraints. This interaction between the substi-mte and the environment could be considered as the smart behavior of all biomaterial. 

Biomaterials, by definition, should possess an inherently low toxic potential, unless their function is to express a specific toxic activity in the site of implantation. This safety requirement is linked to the operative life of the biomaterial, which determines the release probability of toxins from the tissue. 

According to these definitions, one must have a vast field of knowledge or collaborate with different specialties in order to develop and use biomaterials in medicine and dentistry as Table V.l indicates. The uses of biomaterials, as indicated in Table V.2, include replacement of a body part which has lost function due to disease or trauma, to assist in healing, to improve function, and to correct abnormalities. The role of biomaterials has been influenced considerably by advances in many areas of biotechnology and science. For example, with the advent of antibiotics, infectious disease is less of a threat than in former times so that degenerative disease assumes a greater importance. Moreover, advances in surgical technique and instruments have permitted materials to be used in ways which were not possible previously. This section of the handbook is intended to develop in the reader a famdiarity with the uses of materials in medicine and dentistry and with some rational basis for these appHcations. 

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