Fig. (1) Effect of P. gingivalis LPS (a) and MSE (b) on cell viability in hPDL fibroblasts. Cells were treated with various concentrations and cell viability was measured by MTS assay at 24 h after culture. The data are expressed as the percentage of viable cells compared with the nontreated cells. The values (mean ± SD) are the average of three independent experiments performed in triplicate; * indicate significant (p < 0.05).