CoCr porous scaffolds manufactured via selective laser melting in orthopedics: Topographical, mechanical, and biological characterization

Abstract

Over the last decade, advances in additive manufacturing have allowed to obtain complex 3D porous lattice in materials suitable for orthopedic applications. Whereas 3D‐melted titanium alloys have been extensively investigated, little is the current knowledge on the feasibility of bone‐replicating CoCr porous scaffolds manufactured via selective laser melting (SLM). Moreover, the effect of topography on bone cells viability and proliferation has not been fully explored yet. Small cylindrical porous lattices were modeled from micro‐CT images of human trabecular bone, and from the repetition of spherical‐hollow and body‐centered cubic unit cells, and manufactured via SLM from CoCr powder. Macro‐ and microcharacterization of the porous samples were assessed using optical microscope, micro‐CT, and SEM. The scaffolds mechanical properties, measured via ISO testing, compared well with those of the human bone. Osteoblast‐like cells proliferation and viability were assessed in vitro, and compared to those cultured on a standard nonporous implant‐to‐bone interface, showing steady increase on all geometries over time. SEM analysis confirmed the quality of cells morphology, spread, and organization on all lattices. The SLM process appeared not to alter the biocompatibility of CoCr; however, 15–100 μm irregularities and macroalterations were observed in the porous scaffolds with respect to the 3D nominal models. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2343–2353, 2019.

Development of AM Technologies for Metals in the Sector of Medical Implants

“…Advantages and disadvantages of the CoCr alloys[68,92]. Ni) alloys are metals made from a combination of nickel as the primary element and another material such as Ni-Al alloy, Ni-Cr alloy or Ni-Ti alloy.…”

Mechanical characterization and properties of laser-based powder bed–fused lattice structures: a review

“…Furthermore, Leary concluded that the face-and-bodycentered geometry with vertical struts (FBCCZ) has the highest absolute values of strength and modulus [84] while the FCCZ geometry has the best specific strength and modulus compared to other samples [85]. Furthermore, the BBC geometry has been reported to have higher equivalent strength and specific strength than crossing rod unit cell [86], while crossing rod presents higher ultimate and yield strength than circular unit cell [87]. Topological optimization leads usually to cell geometries that often result in improved mechanical performances [88].…”

“…Muller et al [107] found that a certain level of randomization improves the mechanical properties while Raghavendra et al [108] reported regular structures having higher values of strength. Other works tested lattice structures to compare their properties with the natural bone [7,87] or to validate the related FEM simulation [120,121].…”

The integration of pore size and porosity distribution on Ti-6A1-4V scaffolds by 3D printing in the modulation of osteo-differentation

“…Imwinkelried 30 has studied the effects of porosity on mechanical properties of Ti scaffolds and concluded that 50-80% porosity of Ti scaffolds was consistent with natural bone in terms of stiffness and strength. Moreover, based on a well-designed experiment, Caravaggi et al 31 investigated the selective laser melting (SLM) complex of 3D porous lattice CoCr scaffolds such as crossing-rod, trabecular, and circular with pore sizes of approximately 510, 670, and 800 μm, respectively. The research showed favorable biocompatibility and mechanical property of the SLM porous CoCr scaffolds.…”