Background Silicon nitride is a promising biological implant material. As an advanced 3D printing technology, digital light processing technology has high printing accuracy and fast printing speed. At present, there is still a lack of research reports on digital light processing of silicon nitride as dental implant materials.
Objective To study the preparation of silicon nitride dental ceramics by digital light processing technology, evaluate the microstructure and mechanical properties, and preliminarily evaluate its biosafety.
Methods According to GB 30367-2013 and GB / T 10700-2006, the bending strength, fracture toughness and elastic modulus of silicon nitride ceramic by digital light processing were tested by three-point bending method, unilateral pre-cracked beam method and bending method, respectively. The cytotoxicity, cell proliferation and cell viability of silicon nitride ceramic extract treated by digital light processing were detected by mouse fibroblast L929.
Results The bending strength of silicon nitride formed by digital light treatment was 243 MPa, the fracture toughness was 2.6 MPa · m 1 / 2, and the elastic modulus was 125 GPa. The results of cytotoxicity experiments showed that the relative survival rate of L929 cells cultured at different extract concentrations was greater than 80%. Fluorescence staining results of live and dead cells showed that the number of live and dead cells in the extract group had no significant difference with the control group (P＞0.05). Flow cytometry results showed that the proliferation index of the extract group continued to increase, and there was no significant difference in cell cycle compared with the control group (P＞0.05).
Conclusion Digital light processing molded dental silicon nitride ceramics have a typical porous microstructure, good elastic modulus and biosafety, demonstrating the potential for clinical application of dental implant materials.
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