Tailoring Silicon Nitride Surface Chemistry for Facilitating Odontogenic Differentiation of Rat Dental Pulp Cells.

Silicon nitride (SiN) can facilitate bone formation; hence, it is used as a biomaterial in orthopedics. Nevertheless, its usability for dentistry is unexplored. The aim of the present study was to investigate the effect of SiN granules for the proliferation and odontogenic differentiation of rat dental pulp cells (rDPCs). Four different types of SiN granules were prepared, which underwent different treatments to form pristine as-synthesized SiN, chemically treated SiN, thermally treated SiN, and SiN sintered with 3 wt.% yttrium oxide (YO). rDPCs were cultured on or around the SiN granular beds. Compared with the other three types of SiN granules, the sintered SiN granules significantly promoted cellular attachment, upregulated the expression of odontogenic marker genes ( and ) in the early phase, and enhanced the formation of mineralization nodules. Furthermore, the water contact angle of sintered SiN was also greatly increased to 40°. These results suggest that the sintering process for SiN with YO positively altered the surface properties of pristine as-synthesized SiN granules, thereby facilitating the odontogenic differentiation of rDPCs. Thus, the introduction of a sintering treatment for SiN granules is likely to facilitate their use in the clinical application of dentistry.