Figure 5: Cell viability with a collagen membrane (CM), platelet-derived growth factor (PDGF), and CM carrying PDGF evaluated by MTT assay. The percentage of cell viability was calculated by comparing the appropriate luminescent signal to the signal obtained with the control cells. Each value represents the mean ± standard deviation from quadruplicates. As a control (100% viability), the control cells were used. There was no significant difference among CM, PDGF, and CM carrying PDGF.