Fig. 6. Cumulative grouped bar graph (mean + SD) of cytotoxicity test results obtained for the three tested materials. A nonparametric statistical analysis was conducted, employing the Mann–Whitney–Wilcoxon test to investigate for significant differences between the control median and any other concentration group median of a tested sample, where * represents p < 0.05 and ** represents p < 0.01, and ns stands for statistically non-significant differences.