Silicon nitride as a potential candidate for dental implants: Osteogenic activities and antibacterial properties

In this study, we presented that human bone mesenchymal stem cells (hBMSCs) showed superior adhesion and proliferation behaviors on polished silicon nitride (Si3N4). Also, compared to Ti and ZrO2, Si3N4 enhanced the osteogenic activities of hBMSCs indicated by increases in alizarin red S (ARS) staining, Ca2+ concentration, and mRNA expression of RUNX2, OPN, OCN, and COL1. Furthermore, colony formation assays demonstrated significantly better antibacterial activities against oral pathogens Porphyromonas gingivalis (Pg), Staphylococcus aureus (SA), and Escherichia coli (E. coli) on Si3N4 surface than Ti and ZrO2. Live/dead bacterial staining showed a large amount of dead Pg on Si3N4 surfaces. The fact that Si3N4 demonstrated advantages in osteogenic and antibacterial activities over Ti and ZrO2 might be a reason for its potential use as non-metallic dental implant materials. However, more detailed studies with resolution techniques and preclinical studies are needed to confirm the Si3N4’s osteogenic and antibacterial properties. Trial registration number PJ2019-066-001; date of registration: Jun 2019.