Current medical devices certification is challenging due to the update in the regulatory norms and the appearance of gaps (grey zone) due to advances in both the materials and the fabrication technology. A key aspect when reaching a higher level of technology readiness is to have a comprehensive view of the entire process that will lead to the conformity of the devise with the medical device regulation. To have a focus perspective, it is interesting to work on the research project to have defined several key steps for future medical device certification like the definition of the intended use, the documentation of risk analysis and the iterations of risk management, the documentation of design and manufacturing iterations, and the identification of the materials that are included in the medical device. This will lead to the definition the final device that shall be assessed for the biological characterization for conformity assessment under the medical devise regulation. The ISO 10933 series and the MDR devices that are composed of substances or of combinations of substances are discussed in an integrative approach to provide a focus perspective on the biological characterization of a medical device. Furthermore, the concpect of “equivalent” medical devise could be an interesting option for the additive manufacturing of medical devices. For example, custom-made approach could be used as a transition toward certification of series production of medical devices by additive manufacturing.