Osteoinductive Potential of Silicon Nitride Ceramics Versus Mesenchymal Stem Cells

Objectives: Silicon nitride (Si₃N₄) ceramic is employed in spinal implant devices because of its improved osteoconductivity and antibacterial properties. However, the osteoinductivity of Si₃N₄ is yet the object of investigations. This study analyzed the osteoinductive mechanisms of Si₃N₄ versus mesenchymal stem cells (MSCs) by using Raman spectroscopy and ELISA. The goal of this investigation was to determine whether the use of Si₃N₄ could be extended to dental implants.
Methods: In this study, the mouse MSC lines, KUSA-A1, was cultured in the Osteogenic Differentiation Medium on Si₃N₄ or Titanium substrates for 14 days. After 14 days, we observed the Calcified Matrix of KUSA-A1 with a Laser Raman microscope. In addition, the levels of Insulin-like growth factors (IGF-1) and Gla-Osteocalcin (Gla-OC) in the culture supernatant were measured by ELISA.
Results: We found that KUSA-A1 cultured on the Si₃N₄ substrates increased their production of IGF-1 and Gla-OC as compared to titanium substrates. Furthermore, culturing on the Si₃N₄ enhanced the calcification of KUSA-A1 more than titanium.
Conclusions: Si₃N₄ activates MSCs by producing silicic acid with chemical reactions. In addition, the roughness surface of Si₃N₄ synergistically accelerated osteoconductivity with physical stimulation. Si₃N₄ ceramics could rapidly obtain stable osteointegration. In conclusion, Si₃N₄ is extremely promising for dental implants and might contribute to increase the success rate of dental implants.