High strength polymer/silicon nitride composites for dental restorations

Abstract Objectives To fabricate polymer-infiltrated silicon nitride composite (PISNC) and evaluate the potential of PISNC in dental application. Methods Porous silicon nitride (Si 3 N 4 ) ceramics were fabricated through gelcasting and pressureless sintering. Polymer infiltrating was carried out then and composites were obtained after curing of polymer. Flexural strength and microstructures of porous ceramic scaffolds and polymer-infiltrated composites were obtained by three-point bending and SEM, respectively. Phase distributions of polymer-infiltrated ceramics were observed by EDS. Human gingival fibroblast cells (HGFs) were used to evaluate the cytocompatibility and IL-6 release. The cell morphology were observed by SEM. The amount of released IL-6 was investigated using ELISA test system. Results Porosity and mechanical strength of porous ceramics ranged from 45.1 to 49.3% and 171.8–262.3 MPa, respectively. The bicontinuous structure of polymer-infiltrated composites possessed them with excellent mechanical properties. Porosity and mechanical strength of polymer-infiltrated Si 3 N 4 composites ranged from 1.94 to 2.28% and 273–385.3 MPa, respectively. Additionally, the PISNC enhanced the initial adhesion and spreading activity of HGFs compared with PMMA. The PISNC showed similar IL-6 release performance with PMMA samples. Significances The PISNC is a promising candidate for dental restorations and high-load medical applications.