This article tabulates materials that are known to have been used in orthopaedic and/or cardiovascular medical devices. The materials are grouped as metals, ceramics and glasses, and synthetic polymers in order. These tables were compiled from the Medical Materials Database which is a product of ASM International and Granta Design available by license online and as an in-house version. The material usage was gleaned from over 24,000 U.S. Food and Drug Administration (USFDA), Center for Devices and Radiological Health, Premarket notifications (510k), and USFDA Premarket Approvals, and other device records that are a part of this database. The database includes other material categories as well. The usage of materials in predicate devices is an efficient tool in the material selection process aiming for regulatory approval.

Additive manufacturing (AM), or three-dimensional (3D) printing, is a class of manufacturing processes that create the desired geometries of an object, or an assembly of objects, layer by layer or volumetrically. AM has been used extensively for manufacturing medical devices, due to its versatility to satisfy the specific needs of an intended medical field for the product/device. This article provides a comprehensive review of AM in medical devices by the medical specialty panels of the Food and Drug Administration (FDA) Code of Federal Regulations, Parts 862 to 892, including anesthesiology, ear and nose, general hospital, ophthalmic, plastic surgery, radiology, cardiovascular, orthopedic, dental, neurology, gynecology, obstetrics, physical medicine, urology, toxicology, and pathology. It is classified under these panels, and critical reviews and future outlooks are provided. The application of AM to fabricate medical devices in each panel is reviewed; lastly, a comparison is provided to reveal relevant gaps in each medical field.

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.

Bearing in mind the three-legged stool approach of device design/manufacturing, patient factors, and surgical technique, this article aims to inform the failure analyst of the metallurgical and materials engineering aspects of a medical device failure investigation. It focuses on the device "failures" that include fracture, wear, and corrosion. The article first discusses failure modes of long-term orthopedic and cardiovascular implants. The article then focuses on short-term implants, typically bone screws and plates. Lastly, failure modes of surgical tools are discussed. The conclusion of this article presents several case studies illustrating the various failure modes discussed throughout.

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.

This article provides a summary of the biocompatibility or biological response of metals, ceramics, and polymers used in medical implants, along with their clinical issues. The polymers include ultrahigh-molecular-weight polyethylene, nonresorbable polymer, and resorbable polymers.

This article provides highlights of the general process and workflow of creating a 3D-printed model from a medical image and discusses the applications of additively manufactured materials. It provides a brief background on Food and Drug Administration (FDA) classification and regulation of medical devices, with an emphasis on 3D-printed devices. Then, the article discusses two broad applications of 3D printing in craniofacial surgery: surgery and education. Next, it discusses, with respect to surgical applications, preoperative planning, use in the operating room, surgical guides, and implants. The article includes sections on education that focus on the use of 3D-printed surgical simulators and other tools to teach medical students and residents. It briefly touches on the FDA regulations associated with the respective application of 3D printing in medicine. Lastly, the article briefly discusses the state of medical billing and reimbursement for this service.

This article focuses on the analysis of materials and mechanical- (or biomechanical-) based medical device failures. It reviews the failure analysis practices, including evidence receipt, cleaning, nondestructive examination, destructive examination, exemplars analysis, and device redesign. The article examines the common failure modes, such as overload, fatigue, corrosion, hydrogen embrittlement, and fretting, of medical devices. The failure analysis of orthopedic implants, such as permanent prostheses and internal fixation devices, is described. The article reviews the failure mechanisms in some of the more common medical device materials, namely, stainless steels, titanium alloys, cobalt-base alloys, and nitinol. It presents case histories with examples for failure analysis.

This article focuses on the specific aspects of nitinol that are of interest to medical device designers. It describes the physical metallurgy, physical properties, and tensile properties of the nitinol. The article discusses the factors influencing superelastic shape memory effects, fatigue, and corrosion in medical device design. It reviews the biocompatibility of nitinol based on corrosion behavior. The article explains the general principles, potential pitfalls, and key properties for manufacturing, heat treatment, and processing of nitinol.

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.

This article provides an overview of additive manufacturing (AM) methods, the three-dimensional (3D)-AM-related market, and the medical additive manufactured applications. It focuses on the current scenario and future developments related to metal AM for medical applications. The discussion covers the benefits of using 3D-AM technology in the medical field, provides specific examples of medical devices fabricated by AM, reviews trends in metal implant development using AM, and presents future prospects for the development of novel high-performance medical devices via metal 3D-additive manufacturing.

Stainless steels are used for medical implants and surgical tools due to the excellent combination of properties, such as cost, strength, corrosion resistance, and ease of cleaning. This article describes the classifications of stainless steels, such as austenitic stainless steels, martensitic stainless steels, ferritic stainless steels, precipitation-hardening stainless steels, and duplex stainless steels. It contains a table that lists common medical device applications for stainless steels. The article discusses the physical metallurgy and physical and mechanical properties of stainless steels. Medical device considerations for stainless steels, such as fatigue strength, corrosion resistance, and passivation techniques, are reviewed. The article explains the process features of implant-grade stainless steels, including type 316L, type 316LVM, nitrogen-strengthened, ASTM F1314, ASTM F1586, ASTM F2229, and ASTM F2581 stainless steels.

The human internal environment plays a vital role in the friction and wear of implants and prosthetic devices. This article describes the tribological/wear behavior of implants. It discusses the classification of active tribological pairs, namely, amphiarthosis joints and diarthosis joints. The article details the classification of total knee replacement, depending on the type of mechanical stability, including nonconstrained knee replacement, semiconstrained knee replacement, and constrained knee replacement. It also discusses the classifications of passive tribological pairs, namely, total disc replacement in the spine, dental implants, and temporomandibular joint. It describes the various testing methods for characterizing the implant materials used in hip, knee, spine, and dental applications. The article also describes the typical standards used for testing wear behavior of tribological pairs, namely, hip-wear simulation standards, knee-wear simulation standards, and spinal disc-wear simulation standards.

This article tabulates the chemical composition of iron-base, titanium-base, and cobalt-base alloys and illustrates the microstructures of these materials. It discusses the surface morphology and chemistry of oxide-film-covered alloys and provides insights into the interaction. The article illustrates the interfacial structure of a biomaterial surface contacting with the biological environment. It describes the corrosion behavior of stainless steel, cobalt-base alloy, and titanium alloys. The electrochemical methods used for studying metallic biomaterials corrosion are also discussed. The article concludes with information on the biological consequences of in vivo corrosion and biocompatibility.

This article discusses some of the additive manufacturing (AM) based fabrication of alloys and their respective mechanical, electrochemical, and in vivo performance. Firstly, it briefly discusses the three AM techniques that are most commonly used in the fabrication of metallic biomedical-based devices: binder jetting, powder-bed fusion, and directed-energy deposition. The article then characterizes the electrochemical properties of additive-manufactured/processed cobalt-chromium alloys. This is followed by sections providing an evaluation of the biological response to CoCr alloys in terms of the material and 3D printing fabrication. Discussion on the biological response as a function of direct cellular activity on the surface of CoCr alloys in static conditions (in vitro), in dynamic physiological conditions (in vivo), and in computer-simulated conditions (in silico) are further discussed in detail. Finally, the article provides information on the qualification and certification of AM-processed medical devices.

Biomaterials are the man-made metallic, ceramic, and polymeric materials used for intracorporeal applications in the human body. This article primarily focuses on metallic materials. It provides information on basic metallurgy, biocompatibility, chemistry, and the orthopedic and dental applications of metallic biomaterials. A table compares the mechanical properties of some common implant materials with those of bone. The article also provides information on coatings, ceramics, polymers, composites, cements, and adhesives, especially where they interact with metallic materials.

Additive manufacturing (AM) has been growing as a significant research interest in academic and industry research communities. This article presents flexible and biocompatible energy-harvesting devices using AM technology. First, it discusses material selection for achieving piezoelectricity and triboelectricity. Then, the article highlights the structures of energy harvesters and describes their working mechanisms. Next, it covers the additively manufactured implantable piezoelectric and triboelectric energy harvesters. Further, the article describes the 3D-printed wearable energy harvesters as well as their applications. An overview of additively manufactured self-powered sensors is highlighted. Finally, the article discusses the issues for 3D-printed energy harvesters and their roadmap.

Bioprinting has been advancing in the field of tissue engineering as the process for fabricating scaffolds, making use of additive manufacturing technologies. In situ bioprinting (also termed intraoperative bioprinting) is a promising solution to address the limitations of conventional bioprinting approaches. This article discusses the main approaches and technologies for in situ bioprinting. It provides a brief overview of the bioprinting pipeline, highlighting possible solutions to improve currently used approaches. Additionally, case studies of in situ bioprinting are provided and in situ bioprinting future perspectives are discussed.

This article reviews the understanding of corrosion interactions between alloys in complex geometries and in applications where there are significant cyclic stresses and potential for wear and fretting motion. These alloys include iron-base, titanium-base, and cobalt-base alloys. The article discusses the surface characteristics and electrochemical behavior of metallic biomaterials. It summaries the clinical context for mechanically assisted corrosion and describes mechanically assisted crevice corrosion. There have been several tests developed to investigate aspects of mechanically assisted corrosion. The article also explains the scratch test and the in vitro fretting corrosion test.

This article reviews the corrosion interactions between biomedical alloys, in particular iron-base, titanium-base, and cobalt-base alloys, in complex geometries and in applications where there are significant cyclic stresses and potential for wear and fretting motion. It discusses the nature of these metal surfaces and their propensity for corrosion reactions when combined with similar or different alloys in complex restrictive environments within the human body and under loading conditions. The article describes the factors that influence mechanically assisted crevice corrosion. It reviews the tests developed to investigate the aspects of mechanically assisted corrosion of metallic biomaterials: the scratch test and the in vitro fretting corrosion test.