Biosafety evaluation of Li2Si2O5 whisker-reinforced glass-ceramics

Lithium disilicate (Li2Si2O5) glass-ceramic is a commonly used dental ceramic material. In this study, Li2Si2O5 whiskers were prepared by the hydrothermal method, mixed with Li2Si2O5 glass powders, and Li2Si2O5 whisker-reinforced glass-ceramics were prepared by reaction sintering. The biosafety of the new Li2Si2O5 glass-ceramics were evaluated by in vitro cytotoxicity, hemolysis, oral mucosal irritation, acute systemic toxicity, and subacute systemic toxicity (oral route) tests according to ISO 7405/ISO 10993 standards. The cytotoxicity test results showed that the cell growth of the experimental group was good, and the cell number and morphology were not significantly different from those of the blank group (P > 0.05). The toxicity grading for both experimental and blank control groups were 0. The hemolysis rate of the material was 1.25%, which indicated that it did not cause hemolytic reaction. The material was non-irritating to the oral mucosa. In acute systemic toxicity test, animals in the experimental group showed increased body weight, moved freely, with no signs of poisoning. The food utilization rate and relative growth rate (change of the weight) of rats in the subacute systemic toxicity test were not statistically different from those of the control group (P > 0.05). Preliminary evaluation of the biosafety of the Li2Si2O5 whisker-reinforced glass-ceramics showed that it met the existing regulatory standards, and further biosafety experiments can be conducted, following which the material may be expected to be applied in clinical practice.