Production and Characterisation of Titanium Foam Scaffolds as Bone Substitute Materials

Abstract

Studies have confirmed that titanium (Ti) can improve the contact of bone and its surface growth. Titanium foam may, therefore, prove beneficial in aiding healing and the generation of greater power from implant regions. Biomedical methodologies have only recently sought to use porous metal frameworks in copying the structure and mechanical features of bone. When forming and constructing metal foams with the aim of achieving their best features, it is of utmost significance that their mechanical factors and possible failures of mechanism are comprehended. The way they behave mechanically is determined by their microform and their cellular organisation. Differences in density, topology, mechanics of breaks and cellular aluminium, steel and magnesium foam fatigue (mainly not biocompatible) have been researched a lot previously. Nevertheless, for the new biocompatible foams such as the porous titanium foams, there is a lack of comprehension of their failure processes. This report therefore seeks to enhance the basic comprehension of the mechanical functions of titanium foams and new material that can be employed for biomedical use in the coming years. The study spans details on how titanium foams are produced with individual chemical make up of three varied degrees of porosity; namely 60, 70 and 80% and which will define the features of both cancellous and cortical bone. The study also seeks to form a Finite Element Method (FEM) model for analysis of the implants made of titanium form. This would allowfor assessment of the mechanical properties across the various dimensions, compression settings and levels of porosity. This will result in the efficacious design of suitable implants at times of surgery. Uniaxial compression testing was used to examine the performance in the mechanical context together with the compressive strength and the elastic modulus. The mean elastic modulus and yield strength values of the three degrees of porosity of the titanium foam were similar to those attained for human cortical and cancellous bone. Prior to and following compression, a macro and micro assessment of their physical and morphological parameters was carried out to aid in comprehension of the morphological features. This work was supported with the use of electron microscopes (scanning and optical), micro-CT, EDS (Energy-Dispersive X-Ray Spectroscopy) and XRD (X-ray Powder Diffraction analyses and Vickers hardness. Moreover, osteointegration was assessed for two, three and four weeks by immersion of the samples of titanium foam in substances that are similar to body fluid. The primary objective of this study was comprehension of the degree of porosity and organisation of the foam that would adequately form inner connections to enable regeneration of vasculature whilst also mimicking the features of porosity associated with human bones. The best morphological and mechanical features regards human bone were achieved for samples that were 60% porous. However, the optimum mimicking of cancellous human bone was achieved at a degree of 80% porosity. Finite element analyses were carried out in order to simulate the compression behaviour of the titanium foam implants with 60,70 and 80%. The outcomes of these evaluations supported the experimental findings which in turn resulted in model validation. The model was subsequently employed in the examination of distribution of stress within the titanium foam structure of dental implants. The findings of the research showed that the use of the space holder method to produce porous titanium scaffolds had great possibilities in the field of hard tissue engineering. It is therefore anticipated that the findings of this study would be advantageous for the formation of new materials and their employment in the biomedical field.