Cytotoxicity of Indirect Restorative Materials: Cell-viability and Apoptosis on L-929-fibroblasts

Objectives: To assess the biocompatibility of eight different indirect restorative materials by using xCELLigence real time cell proliferation system and Annexin-V‑PI staining.
Methods: A total of 96 samples of Au-alloy(A), Cr-Co-alloy(B), Cr-Co-Ni-alloy(C), fiber-reinforced-resin-blocks(D), resin-nano-ceramic(E), lithium-disilicate-reinforced-ceramics(F), monolithic-zirconia(G) and feldspathic-ceramics(H) were prepared in disc shape (5x2mm, n=12). After sterilization, discs were placed in DMEM and incubated at 37°C. Mediums were collected and filtered from each of four samples in 1^st, 7^th, and 14^th days. 15.000 cells/well were seeded in the e-plate. After 24h incubation, cells were treated with 100 µl medium extracts of materials. Cell impedance was measured every 15 minutes for 190 hours. Apoptosis was analyzed using Annexin-V‑PI staining. Cell indexes were normalized at 24h and slope values were calculated with X-celligence software. One-way ANOVA and Tukey’s multiple range tests were used for statistical analyses (p=0.05).
Results: F showed highest toxicity during the experiment (p<0.001). Although H had toxic effect on the first day, cell viability increased on the 7^th and 14^th days (67.51% and 83.23%) and presented the highest viability levels (p<0.001). Similarly, cytotoxic effects of E and G decreased on the 14^th day and cell viabilities increased to 65% and 54% respectively. C showed moderate toxicity at first, however its toxicity increased at the 7^th and14^th days and cell viability decreased to 25%. A showed the most stable viability values all through the study (43.50%, 42.93% and 42.42%, respectively). Significantly higher apoptosis rates were detected for G and F (70.2% and 64.1% respectively, p<0.05), which were followed by B (54.5%), E (44.2%), D (37.9%), B (33.3%), H (32.7%) and A (25.4%).

Conclusions: With respect to biocompatibility, H presented low cytotoxicity values whereas G and F revealed higher cytotoxicity results. A was the most stable material throughout the cell viability and apoptosis experiments.