3D printing, also known as additive manufacturing, is a manufacturing technology that has been around for more than three decades.(1,2 ) In the last 5 years, however, the industry has seen exponential growth; trending from rapid prototyping to mass production. (3) It is not a traditional manufacturing technique (e.g., molding or subtractive techniques), rather, it is a manufacturing process where a complete object is made through the successive buildup of single layers based on a digital blueprint of finite data. This process enables mass production and customization, and the creation of complex geometries within a single object without the need for different tooling (also known as “complexity for free”).(4) A related key advantage is that this technology provides new design possibilities.(5) Many of the complex geometries and designs made possible by 3D printing are not feasible or practical with traditional manufacturing techniques. Currently, the potentially disruptive nature of 3D printing in mass production and on the traditional manufacturing supply chain seems imminent. 3D printing is also bringing the manufacturing process closer to the end user, for example in dentistry, and furthering its potential to disrupt the current supply chain in a more fundamental way.(6)
These innate technological advantages from 3D printing have numerous implications for healthcare, not all of which have yet to be realized, appreciated, or fully understood. Medical devices are health or medical instruments used in the treatment, mitigation, diagnosis or prevention of a disease or abnormal physical condition that does not achieve its primary purpose through chemical action (as opposed to a drug). (7,8) In the medical devices sector of healthcare, 3D printing enables truly personalized medicine through mass customization of medical devices or treatments, and on-demand production at the point of care. (6) It can also potentially decrease the current cost of production, and the need to store variations of an intended surgical tool or implant.
While many have recognized and advocated the vast potential of 3D printing technology in healthcare, based on recent survey results, hesitance is palpable within the ecosystem, ranging from 3D printing entrepreneurs, device makers, healthcare organizations, to other corporations in the healthcare field. (9) Part of this uncertainty comes from the fact that 3D printing is a relatively new and different manufacturing process from traditional ones and the existing biocompatible materials used for traditional manufacturing processes may not demonstrate similar behaviors if translated for use in 3D printing. For example, in the 3D printing manufacturing process of metal powders, there is partial re-melting and solidification of the initial powder that may change the material physical and/or chemical properties of the printed object.(10) Also, because of the added structural complexity (often an advantage of 3D printing), the behaviors of the final device are also not well known and need to be validated for both “safety” and “effectiveness”. Another example is the 3D printing of objects with non-solid fill (e.g., a honeycomb fill) has been used to decrease their weight and create structures that more closely mimic biological materials (e.g., the internal structure of bone). The cleaning of these complex geometries and the gas or liquid within these structures needs to be evaluated for safety during the regulatory process of a medical device.(10)
The objectives of this paper are to provide clarification and in-depth discussion of the topics below, which are critical elements to the additive manufacturing industry in healthcare:
- Definition of biocompatibility
- Discussion on how biocompatibility is assessed within the current regulations of materials and medical devices by major regulatory agencies
- Summary of how different regulatory agencies are managing the introduction of 3D printing into the healthcare space to date
- List of major available biocompatibility materials and those in development