ABSTRACT
The aim of this study was to compare the cytotoxicity of Mineral Trioxide Aggregate [MTA] and a New Endodontic Cement [NEC] on L929 mouse fibroblasts. Different dilutions [Neat, 1/2, 1/10, 1/100] of fresh and set materials placed adjacent flasks of L929 in DMEM medium. Cellular viability was assessed using MTT assay in three time intervals [24, 48, and 72 h after mixing]. Differences in mean cell viability values between materials were assessed by using the One-way ANOVA and Bonferoni post-test. Optical microscopic analysis of morphology of the untreated control and the cementtreated cell cultures were carried out in all experimental periods. It was indicated that there was not a significant difference in cytotoxicity among the materials of test and between them and the control group. However, there was a statistically significant difference between different time intervals within each group [P