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Introduction

I commenced experimental research into the safety of 3D-printed devices at the time 3D Printing (3DP) was largely considered to be at a “proof of concept stage” in dentistry. I vividly remember how the technology was relatively unknown in my discipline when I arrived on the splendorous Gold Coast, 7 years ago to take up a lecturing position at Griffith University. It is against these backdrops that I would describe the recent hype and the desperate attempt by companies to diversify and innovate competitively as another milestone or perhaps a watershed in the dental specialism concerned with the design and manufacture of devices such as orthodontic splints (Fig.1), surgical guides, and dentures. While it is seemingly laudable that polymers and metals, which form the bulk of dental devices, can now be processed by 3DP, limited scientific evidence exists on their biological safety. It is, therefore, my intention to highlight some pertinent findings from my doctoral study that examined medically-approved photopolymers using the innovative zebrafish embryo model and analytical spectrometry.

Findings

1. All 3D-printed devices will display a varying degree of toxicity subject to physicochemical characteristics of the materials and postprocessing techniques that include disinfection protocols.
2. Resin formulations on the market are constantly evolving, and hence there is a need to independently verify their biological safety as per intended use.
3. New preclinical standards are required for 3D-printed devices bearing in mind the materials and additive processes differ considerably from traditional counterparts.

Recommendations

Since the different materials and additive processes make it nearly impracticable to achieve a consensus, it is recommended that users engaged in biomedically-related 3DP activities adopt the three-tiered approach that may together guarantee optimal results i.e., approved materials, apposite manufacturing parameters and postprocessing. Likewise, caution is required in the use of third-party materials in “open” 3DP systems without approved certifications. To guarantee patient safety, it is high time manufacturers are compelled by legislation to make available to the general public test results for scrutiny and academic reflection. While standards for preclinical testing are bound to lag behind evolving materials and emerging technologies, the gap can be narrowed considerably if urgent steps are taken to revise those in circulation to reflect the trends toward non-traditional medical devices. For instance, it will be preposterous to evaluate dental devices solely on ISO 20795 guidelines when evidence suggests that they may contain other potentially toxic acrylic esters apart from the recommended residual methyl methacrylate. In this regard, qualitative and quantitative analyses of the chemical composition of the printed devices will be more useful for predicting biological safety. Furthermore, dental devices that are likely to leach toxic substances could be scrutinized for acute toxicity using zebrafish, which has a high genetic similarity to humans, and offers economy and ease of quantifying multiple toxicity endpoints (Fig. 2).

Further Reading

Alifui-Segbaya, F. 2018. Toxicological assessment of photopolymers in additive manufacturing using the innovative zebrafish embryo model. PhD Doctorate, Griffith University.

Alifui-Segbaya, F., Bowman, J., White, A. R., Varma, S., Lieschke, G. J. & George, R. 2018. Toxicological assessment of additively manufactured methacrylates for medical devices in dentistry. Acta Biomaterialia, 78, 64-77.

Alifui-Segbaya, F. & George, R. 2018. Biocompatibility of 3D-Printed Methacrylate for Hearing Devices. Inventions, 3, 52.

Alifui-Segbaya, F., Varma, S., Lieschke, G. J. & George, R. 2017. Biocompatibility of Photopolymers in 3D Printing. 3D Printing and Additive Manufacturing, 4, 185-191.

Biographical Note

Dr Frank Alifui-Segbaya is a Lecturer at the School of Dentistry and Oral Health, Griffith University. He has since 2005 served in different capacities as an academic, a technologist and research scientist in Africa, Europe, and Australia. Frank has published widely on biomedical applications of additive manufacturing in high impact journals including “Additive Manufacturing”, “Acta Biomaterialia”, and “3D Printing and Additive Manufacturing”. He provides expert opinion in his area of expertise to the scientific community, and reviewer services to copious international journals. He is internationally recognised for his innovative research into preclinical assessment of medical devices in 3D Printing and the applications of zebrafish embryo model to toxicity screening of biomedical polymers. Frank is a member of the Academy of Dental Materials. His research interests are biomaterials, additive manufacturing, zebrafish genetics and toxicology, and the applications of digital manufacturing to dentistry. His learning and teaching interests are curriculum development, international benchmarking and external assessment.

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After 6 months of extensive research and interviews, 3DHEALS team is finally ready to publish this anticipated white paper explaining the complex world of biocompatible materials for 3D printing/ 3D printed medical devices.

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. 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. 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.
The objectives of this white 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.We are open to feedback and suggestions for a future edition. We are very honored and excited to be part of this innovative journey.

Buy Now. 

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