Siloxane functionalized phosphorylcholine (PC) or sulfobetaine (SB) macromolecules (PCSSi or SBSSi) were synthesized to act as surface modifying agents for degradable metallic surfaces to improve acute blood compatibility and slow initial corrosion rates. The macromolecules were synthesized using a thiol-ene radical photopolymerization technique and then utilized to modify magnesium (Mg) alloy (AZ31) surfaces via an anhydrous phase deposition of the silane functional groups. X-ray photoelectron spectroscopy surface analysis results indicated successful surface modification based on increased nitrogen and phosphorus or sulfur composition on the modified surfaces relative to unmodified AZ31. In vitro acute thrombogenicity assessment after ovine blood contact with the PCSSi and SBSSi modified surfaces showed a significant decrease in platelet deposition and bulk phase platelet activation compared with the control alloy surfaces. Potentiodynamic polarization and electrochemical impedance spectroscopy data obtained from electrochemical corrosion testing demonstrated increased corrosion resistance for PCSSi and SBSSi modified AZ31 versus unmodified surfaces. The developed coating technique using PCSSi or SBSSi showed promise in acutely reducing both the corrosion and thrombotic processes, which would be attractive for application to blood contacting devices, such as vascular stents, made from degradable Mg alloys.

This study compares the mechanical properties and wear ability of five CAD/CAM (computer-aided design/computer-aided manufacturing) millable dental blocks. All the discs, including Amber Mill Hybrid, Vita Enamic, Katana Avencia, Lava Ultimate, and Amber Mill, were cut in dimensions of 1.2 mm in thickness and 12 mm in diameter, polished to a machined surface, and immersed in distilled water for seven days. Vickers hardness was measured and the indentations were observed using microscope. The discs were brushed under a 150 g load. Mean surface roughness (Ra) and topography were determined after 100,000 cycles. Finally the biaxial flexure strength of the discs was measured and the broken surfaces were observed using scanning electron microscopy (SEM). The data was subjected to Weibull analysis. All data were analyzed by one-way analysis (ANOVA). The results of Vickers hardness are shown as: Amber Mill > Vita Enamic > Amber Mill Hybrid > Lava Ultimate > Katana Avencia. Katana Avencia showed the highest volume percentage reduction and the roughest surface after toothbrushing. The biaxial flexural strength is shown as: Amber Mill > Katana Avencia > Lava Ultimate > Amber Mill Hybrid > Vita Enamic. All the tested materials exhibited varying degrees of mass loss and surface roughness. The properties of the composite materials are related to the filler content, filler volume, and polymerization methods.

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This study was conducted to investigate the biocompatibility of Mg-Zn-Ca ternary alloy as a biodegradable material. The casting alloy underwent anodization in an alkaline electrolyte at current density 300 mA/cm(2) and frequency 50 Hz to obtain porous oxide layer. Plasma anodization film using pulse was shown to form irregular porous oxide film. As a result of corrosion test, the corrosion current was shown to decrease and the corrosion voltage was shown to increase in the anodized group, which showed the improvement of corrosion resistance after surface treatment. Sodium silicate (0.1 M) was directly oxidized due to high charges caused by spark and then formed SiO(2), and the compounds produced inside the film were shown MgO, Mg(2) SiO(4), and SiO(2.) In the histological examination in rats, all samples of the untreated group were shown to be absorbed 3 weeks later into the body. After the magnesium alloy was implanted, blood vessel expansion and tissue change were shown in the adjacent tissues. However, the changed tissues were shown to return to normal muscle tissues 4 weeks later when the alloy was completely absorbed. These results suggest that anodized Mg-35Zn-3Ca alloy has good biocompatibility in vivo and controls the absorption rate of biomaterials.