Fig. 3

(A) Comparison of MTT cytotoxicity test results from three different laboratories (CBMR, OTS, and CDENT) using the L929 cell line and primary cells isolated from three different human tissues, (B) fibroblast-like synoviocytes (FLS) (n = 3 patients), (C) human chondrocytes (n = 3 patients), and (D) human umbilical vein endothelial cells (HUVEC) (n = 4 patients). All data are expressed as percent viability (least square arithmetic means ± the 95% confidence intervals), relative to values in the presence of the negative control (glass, 100% viability). Cytotoxic carboxylate cement (cem) was used as positive control. Values above 70% viability (dashed line) were considered to confirm the absence of cytotoxic effects of the tested sample. Of note, 95% CI error bars that do not cross the dotted horizontal 70% line are significantly (p < 0.05) different from 70%