In this work, a series of biodegradable pure iron, Fe-30Mn and Fe-30Mn-Ag alloys were developed by using a rapid solidification technology. A fine a-Fe dendrite was formed in pure iron, resulting in a high compressive yield strength of above 300 MPa. The Fe-30Mn alloy doped with only 1% Ag exhibited a significant increase in the degradation rate in simulated body fluid due to the precipitation of Ag-rich particles in alloy matrix and the induction of the microgalvanic corrosion. In addition, the novel Fe-30Mn-Ag alloy also exhibited a good magnetic compatibility and offered a closely approaching requirement for biodegradable medical applications.

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ᅟA graded nano-glass/zirconia (G/Z) system has been developed via the infiltration of nano-glass into a nano-zirconia surface, which is advantageous for robust core-veneer bonds. The aging issue is a key for yttrium-stabilized tetragonal zirconia polycrystals (Y-TZPs), and therefore, it is necessary to evaluate the influence of aging degradation on the biocompatibility of G/Z systems before their possible clinical application. Herein, such biocompatibility testing was performed with human gingival fibroblasts (HGFs) seeded onto unaged/aged G/Z and Y-TZP for 2–72 h. Assessments included an oral mucous membrane irritation test in conjunction with analyses of cell viability, cell adhesion, and oxidative stress responses. Significant metabolic decreases in aged G/Z- and Y-TZP-treated cells were observed at 72 h. G/Z did not elicit any significant differences in cell viability compared with Y-TZP over 72 h both before and after aging. The oxidative stress data for the aged G/Z- and Y-TZP-treated cells showed a significant increase at 72 h. The G/Z specimens did not elicit any significant differences in ROS production compared with Y-TZP over 72 h both before and after aging. The cell adhesion rates of both G/Z and Y-TZP increased significantly after aging. The cell adhesion rates of G/Z and Y-TZP were not significantly different before and after aging. According to the oral mucous membrane irritation test, scores for macroscopic and microscopic observations for both the aged G/Z and unaged G/Z sides were 0, demonstrating no consequent irritation.ConclusionsThe excellent biocompatibility of G/Z indicates that it has potential for future clinical applications.

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