|Tuesday, August 24|
Mechanical properties of Mg-Ag wires with 2, 4 and 6 wt.% Ag
* Björn Wiese, Helmholtz-Zentrum Geesthacht, Institute of Metallic Biomaterials, Germany
Sebastian Meyer, Helmholtz-Zentrum Geesthacht, Institute of Metallic Biomaterials
Daniela Sanders, Helmholtz-Zentrum Geesthacht, Institute of Metallic Biomaterials
Thomas Ebel, Helmholtz-Zentrum Geesthacht, Institute of Metallic Biomaterials
Regine Willumeit-Römer, Helmholtz-Zentrum Geesthacht, Institute of Metallic Biomaterials
he application of Mg wires as suture or splinting material is already a dream since the beginning of the 20th century1. The use of Mg was always lim-ited due to the low ductility during bending, which was noticed as low knotting strength ("Knüpffestigkeit") for surgical techniques. The ductility can be improved by the manufacturing technique or by alloying with appropriate ele-ments. In this study Ag was used to improve the ductility of Mg2 and add antibacterial properties3, which is the perfect combination for an implant with high surface to volume ratio and demands for ductility. Therefore, two different diameters of wires were manufactured out of Mg-2Ag, Mg-4Ag and Mg-6Ag and investigated with respect to me-chanical and microstructural properties.
Grain refinement in cold drawn Mg-xAg wires
* Sebastian Meyer, Helmholtz Zentrum Hereon, Germany
Björn Wiese, Helmholtz Zentrum Hereon
Thomas Ebel, Helmholtz Zentrum Hereon
Regine Willumeit-Römer, Helmholtz Zentrum Hereon
Wires have many potential applications as a biomaterial such as cardiovascular stents, coronary guide catheter, Kirschner wires (K-wire), orthodontic arch wires, ligature wires and surgical sutures. In the frequent annealing steps after cold drawing, the microstructure recrystallizes and recovers its ductility.
Characterization of newly developed Zn-Mn-Ca biodegradable alloy
* Nafiseh Mollaei, Iran University of Science and Technology, Iran (Islamic Republic of)
S. Mahmood Fatemi, Shahid Rajaee Teacher Training University
Seyed Hossein Razavi, Iran University of Science and Technology
Mohammad Reza Aboutalebi, Iran University of Science and Technology
A biodegradable stent as new generation of cardiovascular stents can overcome many of the side effects of permanent ones. Since 2011, researches have shifted towards bioabsorbable zinc. However, Zn’s poor mechanical properties have propelled researchers to search for Zn alloys with improved mechanical properties via elemental composition and/or processing manipulation.In this work a new zinc alloy containing magnesium and calcium elements was developed and characterized.
FEA model of implant-in-bone
* Yang Liu, Loughborough University, United Kingdom
with the rising interest in bioresorbable magnesium bone implants, it becomes difficult to translate outcomes observed in small animal models. Preclinical study using rabbits or sheep allow mimicking of the corresponding structural elements close to human scale, but it does not reflect the dynamic of corrosion and bone healing at a scale comparable to human biomechanics. Computational modelling allows quantitative representation of the dynamic of corrosion and bone regeneration in both spatial and time domains. A virtual system will be established with structural components mapping to the systems of Mg implants to fix a bone fracture. Finite element analysis will be used to examine the physical interaction between the fractured bone models and the standard fixation devices and the stability of the standard fixation device with no corrosion and initial corrosion.
Discussion - Short Oral Presentation
Microstructural characteristics of biodegradable Mg-Ti bonding materials for biomedical applications
* Naritoshi Aoyagi, National Institute of Technology, Nagaoka College, Japan
Taiki Nagai, National Institute of Technology, Nagaoka College
Makoto Inoue, National Institute of Technology, Toyama College
Taiki Nakata, Nagaoka University of Technology
Shigeharu Kamado, Nagaoka University of Technology
In this study, pure titanium-magnesium bonding materials have been produced by spark plasma sintering technique to provide a biodegradable layer on pure titanium substrate. It has been focused on an valuation of microstructure and mechanical behavior of the bonding materials sintered by using magnesium powders. A filing and sintered magnesium showed a higher hardness and an improved shear strength than CP-magnesium sintering. It is considered that many strains have induced into powders when filing from pure ingot. The surface on magnesium powder was oxidized in natural environment, and this magnesium oxide can be bonded to the surface of titanium. These oxide layers exist at the interface and it affects to the bonding strength.
Method for prediction of 3D strain distribution in Mg-based orthopaedic devices
* Aditya Joshi, University of Canterbury, New Zealand
Mark Staiger, University of Canterbury
George Dias, University of Canterbury
The neurocranium (and parts of the viscerocranium) are unique boney elements in mammals, not required to bear regular cyclic loadings. However, metallic devices used for cranial repair (e.g. plates, mesh, screws, etc.) typically undergo permanent deformation (strain) during implantation. In particular, miniplates are hand-shaped by the surgeon to follow the contour of the surface of the cranial bones during implantation. Accordingly, it is hypothesised that the plastic strain may induce changes in the corrosion behaviour of metallic bioresorbable miniplates (e.g. Mg alloys).1However, a challenge in examining this hypothesis is determining the strain distribution generated within a miniplate following such deformations, while also taking into account the tensile-compressive asymmetry associated with Mg alloys. Presently, the combination of 3D laser scanning and finite element method (FEM) is used to estimate strains induced during the implantation of a Mg alloy miniplate.