Abstract: BACKGROUND: In previous studies, glass materials were infiltrated into 5Y-PSZ ultra-translucent zirconia by a double sintering method to prepare 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia materials that can maintain high transparency and high flexural strength.
OBJECTIVE: To evaluate the in vitro biocompatibility of 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia materials.
METHODS: (1) Glass materials were infiltrated into 5Y-PSZ ultra-translucent zirconia by double sintering to prepare 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia. 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia (or 5Y-PSZ ultra-translucent zirconia, 3Y-TZP transparent zirconia) was placed in DMEM culture medium containing 10% fetal bovine serum for 12, 24 and 72 hours, and the surface area ratio of culture medium to sample was 3 mL/cm2, and the 12-, 24- and 72-hour material extracts were obtained. (2) After culturing mouse fibroblast L929 for 24 hours, the original culture medium was discarded and divided into 7 groups for culture: the control group was replaced with DMEM culture medium containing 10% fetal bovine serum by volume, and the other 6 groups were replaced with 24-hour extract of 3Y-TZP transparent zirconia, 24-hour extract of 5Y-PSZ ultra-translucent zirconia, 24-hour extract of 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia, 72-hour extract of 3Y-TZP transparent zirconia, 72-hour extract of 5Y-PSZ ultra-translucent zirconia, and 72-hour extract of 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia. After 1, 3, and 5 days of culture, cell growth was observed under a microscope, and the cell proliferation rate was obtained by CCK-8 assay to determine cytotoxicity. (3) Human anticoagulated blood was mixed with 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia, 5Y-PSZ ultra-translucent zirconia, and 3Y-TZP transparent zirconia, and the hemolysis rate was detected after 0.5 hours. Human anticoagulated blood was mixed with 12-hour extract of 3Y-TZP transparent zirconia, 12-hour extract of 5Y-PSZ ultra-translucent zirconia, and 12-hour extract of 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia, and the hemolysis rate was detected after 0.5 hours.
RESULTS AND CONCLUSION: (1) Under the microscope, it could be seen that the number of cells in each group increased with the extension of culture time, and the cell morphology of each experimental group was basically the same as that of the control group. The cytotoxicity grade of the 24-hour extract of 3Y-TZP transparent zirconia group on the first day of culture was grade 0, and the cytotoxicity grade of the other experimental groups at each time period was grade 1. (2) Neither the material nor the material extract caused obvious hemolytic reaction, and the hemolytic rate was less than 5%. (3) The results showed that 5Y-PSZ-YGI graded glass infiltrated ultra-translucent zirconia had no significant effect on the growth and proliferation of mouse fibroblasts L929, and did not cause hemolytic reaction with human blood, and had good in vitro biocompatibility.

Key words: graded glass infiltrated ultra-translucent zirconia, biocompatibility, ultra-translucent zirconia, transparent zirconia, cytotoxicity, hemolysis rate, biomaterial, engineered oral material