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The low fracture toughness and sensitivity to low-temperature degradation (LTD) are the primary reasons for the suboptimal long-term performance of dental zirconia. Composite ceramics of zirconia have gained popularity due to their ability to combine the benefits of various reinforcements. In this study, Al2O3–SrAl12O19–3Y/4Y/5Y–ZrO2composite ceramics were fabricated using the Pechini method, and the optimal sintering temperature and time were investigated. The relative density, microstructure, grain size, mechanical properties, and LTD resistance of the samples were characterized. The results indicated that the composite achieved optimal performance when sintered at 1500 °C for 3 h. Al2O3and SrAl12O19primarily influence the properties of the zirconia composite ceramics by modulating their density and grain size. With an increase in the content of Al2O3and SrAl12O19, the relative density first increases and then decreases, while the grain size exhibits an inverse trend, resulting in an initial increase followed by a decrease in fracture toughness. Additionally, the rate of increase in the m-phase fraction of the zirconia composite slowed down, but it reached a similar level after 64 h of LTD. The incorporation of 8 vol% Al2O3and 8 vol% SrAl12O19into 3Y–ZrO2resulted in a ceramic composite with the highest fracture toughness values and acceptable LTD sensitivity, measured at 5.23 ± 0.25 MPa m1/2and 48.35 ± 5.70% m-phase (LTD 64 h), respectively. This composite also exhibited high bending strength (990.09 MPa) and hardness (16.52 GPa), making it a promising alternative to conventional 3Y-TZP ceramics commonly used in dentistry.

Zirconia abutments and restorations have improved the aesthetic appeal of implant restoration, yet peri-implantitis poses a significant threat to long-term success. The soft tissue surrounding implants is a crucial biological barrier against inflammation and subsequent bone loss. Peri-implantitis, akin to periodontitis, progresses rapidly and causes extensive tissue damage. Variations in tissue structure significantly influence disease progression, particularly the lower vascular density in peri-implant connective tissue, compromising its ability to combat infection and provide essential nutrients. Blood vessels within this tissue are vital for healing, with angiogenesis playing a key role in immune defense and tissue repair. Enhancing peri-implant soft tissue angiogenesis holds promise for tissue integration and inflammation control. Microgroove surfaces have shown potential in guiding vessel growth, but using subtractive technologies to carve microgrooves on zirconia surfaces may compromise mechanical integrity. In this study, we utilized inkjet printing to prepare bioactive silk fibroin microgrooves (SFMG) coating with different sizes on zirconia surfaces. SFMG coating, particularly with 90 µm width and 10 µm depth, effectively directed human umbilical vein endothelial cells (HUVECs) along microgrooves, promoting their proliferation, migration, and tube formation. The expression of vascular endothelial growth factor A and fibroblast growth factor in HUVECs growing on SFMG coating was upregulated. Additionally, the SFMG coating activated the PI3K-AKT pathway and increased glycolytic enzyme gene expression in HUVECs. In conclusion, SFMG coating enhances HUVEC growth and angiogenesis potential by activating the PI3K-AKT pathway and glycolysis, showing promise for improving tissue integration and mitigating inflammation in zirconia abutments and restorations.