Production and Characterization of a 316L Stainless Steel/β-TCP Biocomposite Using the Functionally Graded Materials (FGMs) Technique for Dental and Orthopedic Applications

Abstract

Metallic biomaterials are widely used for implants and dental and orthopedic applications due to their good mechanical properties. Among all these materials, 316L stainless steel has gained special attention, because of its good characteristics as an implantable biomaterial. However, the Young’s modulus of this metal is much higher than that of human bone (~193 GPa compared to 5–30 GPa). Thus, a stress shielding effect can occur, leading the implant to fail. In addition, due to this difference, the bond between implant and surrounding tissue is weak. Already, calcium phosphate ceramics, such as beta-tricalcium phosphate, have shown excellent osteoconductive and osteoinductive properties. However, they present low mechanical strength. For this reason, this study aimed to combine 316L stainless steel with the beta-tricalcium phosphate ceramic (β-TCP), with the objective of improving the steel’s biological performance and the ceramic’s mechanical strength. The 316L stainless steel/β-TCP biocomposites were produced using powder metallurgy and functionally graded materials (FGMs) techniques. Initially, β-TCP was obtained by solid-state reaction using powders of calcium carbonate and calcium phosphate. The forerunner materials were analyzed microstructurally. Pure 316L stainless steel and β-TCP were individually submitted to temperature tests (1000 and 1100 °C) to determine the best condition. Blended compositions used to obtain the FGMs were defined as 20% to 20%. They were homogenized in a high-energy ball mill, uniaxially pressed, sintered and analyzed microstructurally and mechanically. The results indicated that 1100 °C/2 h was the best sintering condition, for both 316L stainless steel and β-TCP. For all individual compositions and the FGM composite, the parameters used for pressing and sintering were appropriate to produce samples with good microstructural and mechanical properties. Wettability and hemocompatibility were also achieved efficiently, with no presence of contaminants. All results indicated that the production of 316L stainless steel/β-TCP FGMs through PM is viable for dental and orthopedic purposes.

Functionally graded additive manufacturing for orthopedic applications

“…The FGAM enhances the microstructure and mechanical characteristics, which could be considered important for orthopedic applications. Also, the SEM analysis of various FGM composites have good layering and smooth transition from one material to other which may reduce brittle fractures for FGAM orthopedic implants 161 . In addition, the introduction of artificial intelligence and machine learning techniques can provide optimal grading methods of material, temperature, porosity, microstructure etc.…”

Study on Optimization Strategy for the Composition Transition Gradient in SS 316L/Inconel 625 Functionally Graded Materials

“…Functionally graded materials (FGMs) are advanced composite materials in which a gradient change in chemical composition or microstructure from one side to the other leads to corresponding changes in these materials’ mechanical properties [ 1 , 2 ]. Additive manufacturing (AM) technology, renowned for its layer-by-layer fabrication process, stands out due to its adaptability, high efficiency and ability to construct intricate components, making it the preferred method for producing metal FGMs [ 3 ].…”

In vitro comparative study of red blood cell and VWF damage on 3D printing biomaterials under different blood-contacting conditions

“…Among them, acrylic, PCISO, and Somos EvoLVe 128 are often used in medical fixtures and injection instruments while stainless steel is commonly used in body implantable devices. 14–18…”

“…Among them, acrylic, PCISO, and Somos EvoLVe 128 are often used in medical fixtures and injection instruments while stainless steel is commonly used in body implantable devices. [14][15][16][17][18] The average shear stress of the normal circulatory system in the human body is approximately 1-7 Pa. [19][20][21][22][23] To exclude the blood damage caused by supraphysiological shear stress, the two experimental platforms in this study were controlled within the range of physiological shear stress. In addition, most of the previous studies only focused on blood damage induced by materials in a static state.…”