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

Silicon nitride (Si N ) 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 Si N granules for the proliferation and odontogenic differentiation of rat dental pulp cells (rDPCs). Four different types of Si N granules were prepared, which underwent different treatments to form pristine as-synthesized Si N , chemically treated Si N , thermally treated Si N , and Si N sintered with 3 wt.% yttrium oxide (Y O ). rDPCs were cultured on or around the Si N granular beds. Compared with the other three types of Si N granules, the sintered Si N 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 Si N was also greatly increased to 40°. These results suggest that the sintering process for Si N with Y O positively altered the surface properties of pristine as-synthesized Si N granules, thereby facilitating the odontogenic differentiation of rDPCs. Thus, the introduction of a sintering treatment for Si N granules is likely to facilitate their use in the clinical application of dentistry.