Titanium scaffolds for osteointegration: mechanical, in vitro and corrosion behaviour

Abstract

While titanium has been successful as an orthopaedic or dental implant material, performance problems still persist concerning implant-bone interfacial strength and mechanical modulus mismatch between metal and tissue. Porous structures are an advantageous alternative because the elastic modulus can be adjusted to match that of bone, thereby preventing bone resorption. Furthermore, to achieve early and strong stabilization theses structures may be coated with bioactive deposits, as hydroxyapatite. In the present work, titanium porous scaffolds were produced from TiH(2) slurry by a replication sponge reactive sintering method, and coated with hydroxyapatite by the sol-gel process. The obtained structures were microstructurally and mechanically characterized. Their in vitro bioactivity was investigated by soaking in a simulated body fluid (SBF). Electrochemical characterization was also performed in order to evaluate the effect of coating on corrosion resistance. The scaffolds exhibit a three-dimensionally interconnected porous structure that can be mechanically and morphologically compared to trabecular bone. Their in vitro bioactivity suggests potential for osseous integration. Coating also improves corrosion resistance in physiologically saline environment.

Specific Yielding of Selective Laser-Melted Ti6Al4V Open-Porous Scaffolds as a Function of Unit Cell Design and Dimensions

“…However, due to this irregularity, controlling the mechanical properties and geometrical parameters, e.g., pore size or defined structural modulus, is complicated. Pore sizes in the range of 100-600 µm were found in one specimen [18]. Therefore, as it seems, irregular structures are less suited for fabricating load bearing implants with defined mechanical properties.…”

“…In order to reduce the risk of stress shielding, metal alloy implant components can be fabricated for instance with open-porous structures that provide an elastic modulus low enough for this specification [9][10][11][12][13][14]. Open porous structures were generated and tested as irregular [15][16][17][18] and regular or non-stochastic scaffolds [9,10,[19][20][21][22][23][24][25][26]. Since trabecular bone is irregular, irregular structures may be a more authentic imitation than regular ones.…”

“…For this purpose, it is necessary to adapt the mechanical properties according to patient-specific requirements. This includes e.g., a similar elastic modulus to human cortical bone (i.e., [15][16][17][18][19][20] [4,28].…”

New Development of Titanium Wire Ball as Vertebra Substitute

“…The Young's modulus of the HApPulse-AO-TWB was 2-3 times higher than that of the TWB, probably due to the formation of the oxide film and the fixation of HAp onto the surface. The Young's moduli of TWBs and HAp-Pulse-AO-TWBs, except for the TWB with 87% porosity, were found to be comparable to those of cancellous bones, 19) and could therefore possibly prevent new fractures caused by mismatch between the bone filler material and existing bone.…”

Bone Graft Substitutes for Bone Defect Regeneration. A Collective Review

“…Several metallic scaffolds are used to provide support for bone OPEN ACCESS http://scidoc.org/IJDOS.php defect regeneration, such as titanium [74], stainless steel [75], and aluminum [76], these metals are mechanically strong but are not biodegradable and release toxic metallic ions that lead to inflammatory cascades, allergic reactions, and tissue loss [77]. The essential abuse of metallic scaffolds is the deficiency of biological realization on the material surface.…”