Comparative Evaluation of the Cytotoxicity of Two Materials: Calcium Hydroxide Powder, Calcium Hydroxide Reinforced with Chlorhexidine onL929 Fibroblasts by MTT Assay

Background&Aims: Themajor objective of root canal treatment is to disinfect the entire root canal system, which requires that all contents of the root canal system be eliminated as possible sources of infection. This goal may be accomplished using mechanical instrumentation and chemical irrigation. To reduce or eliminate bacteria various irrigation solutions have been applied during the treatment. This research aimed to determine thecytotoxicity of calcium hydroxide powder as compared with calcium hydroxide reinforced with chlorhexidine. Method: This study was carried out using on experimental-laboratory method on L929 fibroblasts based on cell culture and the direct effect of materials on cell line culture .The material to be tested were evaluated every 1,12,24,48and 72 hours by MTT(Metheyltetrazilium bromide) test.In this study L929 cells which not treated with any materials were used as negative control.The data related to the given materials were read by Elias(enzyme-linked immunosorbent assay) instrument. And then were analyzed with SPSS software and one-way ANOVA. Results: Both materials in 0.016 up to 0.00025 concentrations suppressed proliferation. There was a significant difference in various dilutions and different time periods (1,12,24,48,72 hours)(p<0.05).Calcium hydroxide reinforced with chlorhexidineand calcium hydroxide powderin 0.016 concentration and 72 hour showed 75% and 45% cell cytotoxicity,respectively. Conclusion: Cell cytotoxicity of calcium hydroxide reinforced with chlorhexidine is more than that of other materials. Since calcium hydroxide reinforced with chlorhexidine have a higher antimicrobial effect,it is cautiously recommended as a sealing material between treatment(provided that it slightly penetrate to periapical tissues )