This article outlines the selection criteria for choosing an implant material for biomedical devices in orthopedic, dental, soft-tissue, and cardiovascular applications. It details the development of various implants, such as metallic, ceramic, and polymeric implants. The article discusses specific problems associated with implant manufacturing processes and the consequent compromises in the properties of functionally graded implants. It describes the manufacturing of the functionally-graded hip implant by using the LENS process. The article reviews four different types of tissue responses to the biomaterial. It discusses the testing methods of implant failure, such as in vitro and in vivo assessment of tissue compatibility.

Polymers offer a wide range of choices for medical applications because of their versatility in properties and processing. This article provides an overview of polymeric materials and the characteristics that make them a unique class of materials. It describes the ways to classify polymers, including the polymerization method, how the material deforms, or molecular origin or stability. The article contains tables that list common medical polymers used in medical devices. It explains the medical polymer selection criteria and regulatory aspects of materials selection failure analysis and prevention. Failure analysis and prevention processes to determine the root cause of failures that arise at different stages of the product life cycle are reviewed. The article describes the mechanisms of plastic product failure analysis. It discusses the trends in the use of medical polymers, such as high-performance polymers for implants, tissue engineering, and bioresorbable polymers.