effect of calcium hydroxide on the sealing properties of MTA apical barrier

The aim of this study was to evaluate the effects of remnant root canal medicament, calcium hydroxide on the short and long term sealing ability of mineral trioxide aggregate [MTA] apical barrier. Fifty single-rooted teeth were prepared and apical resorptions were made using sulfuric acid. The teeth were allocated into two experimental groups and two control groups. In group 1, calcium hydroxide was placed into canals for one week. In group 2, no medication was placed. In both groups, a 4-mm MTA plug was placed in the root canals. The remaining portion of the canal was filled with gutta-percha/sealer. The microleakage was evaluated after 7 days and 3 months using fluid filtration technique. Repeated measurement ANOVA was used for statistical analysis. There was no significant difference in sealing ability between the two groups in either time periods. In both groups, microleakage decreased after three months but this decrease was not statistically significant. Medication with calcium hydroxide had no adverse effect on the short and long-term sealing properties of MTA plug

Cytotoxic effect of a new endodontic cement and mineral trioxide aggregate on L929 line culture

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