The need for implant materials for hard tissue replacements have been increasing with a fast pace. Keeping this in mind, the main goal of this work was to develop craniomaxillofacial implants for patient specific implants (PSI) applications, with a minimal stress shielding effect, being a major problem for metallic implants such as Ti [1]. Combinations of sheet-like metal-polymer-metal sandwich materials (SMs) were chosen as the ideal material structure. The idea of SMs is nature based, as structures such as a human bone, beak of birds are generally comprised of SMs to maximize its performance with the minimum use of material and weight [2]. These composites provide several benefits for biomedical applications, such as tuneable mechanical properties, along with great vibrational and thermal insulation properties. To make the implants biocompatible Ti was used as skin material along with PMMA as core material. As the bonding between them also needs to be biocompatible, a “grafting from” process was applied to graft PMMA on Ti [3]. This grafted PMMA was used as an adhesive to achieve a good bonding between the metal and the polymer. The bonding was attained via fusion bonding.

The thermal, vibrational and shaping possibilities of these SMs was investigated. SMs showed significantly better thermal and vibrational properties than that of Ti. The shaping possibilities of these SMs for PSI applications were investigated via V-bending and deep drawing tests. When tests were performed at a temperature range where these polymers have sufficient ductility, the SMs were able to be shaped without failure. The results illustrate the promising possibility of applying nature-based SMs for CMF application.

Figure 1. V-bending of Ti-PMMA SMs. Where at room temperatura (RT) it had early delamination, at 80 °C it was able to bent without problems.

References

[1] N. Sumitomo, K. Noritake, T. Hattori, K. Morikawa, S. Niwa, K. Sato, M. Niinomi, Experiment study on fracture fixation with low rigidity titanium alloy: Plate fixation of tibia fracture model in rabbit, J Mater Sci Mater Med. 19 (2008) 1581–1586. https://doi.org/10.1007/s10856-008-3372-y.

[2] M. Rahmani, A.M. Petrudi, Optimization and experimental investigation of the ability of new material from aluminum casting on pumice particles to reduce shock wave, Periodica Polytechnica Mechanical Engineering. 64 (2020) 224–232. https://doi.org/10.3311/PPME.15983.

[3] M. Reggente, M. Harhash, S. Kriegel, P. Masson, J. Faerber, G. Pourroy, H. Palkowski, A. Carradò, Resin-free three-layered Ti/PMMA/Ti sandwich materials: Adhesion and formability study, Compos Struct. 218 (2019) 107–119. https://doi.org/10.1016/j.compstruct.2019.03.039.