Biocompatibility evaluation of MTA mixed with planet- mediated Nano silver using MTT assay

Abstract

MTA is widely used as a biomaterial in procedures such as repair of perforations, obturation of root-end cavities, pulpotomy and apexification. MTA is a bioactive material and can form a layer of hydroxyapatite or apatite carbonate on its surface. Formation of this intermediary layer results in a chemical bond between MTA and dentinal walls. The aim of the present study was to evaluate the biocompatibility of MTA mixed with plant-derived silver nanoparticles using the MTT assay. Materials and Methods In the present study, the human tooth pulp stem cells were cultured on DMEM/F12 culture medium containing 20% fetal bovine serum (FBS), 2-Mm glutamine and 100 U/mL of penicillin and 100 mg/mL of streptomycin, followed by incubation under 5% CO2 at 37ºC. The cells were passaged when their concentration in the flask reached 80%. The following freezing technique was used for long-term storage and provision of a cell bank of tooth pulp stem cells. To carry out the test, 7000 cells were cultured in each well of a 96-well plate. After 24 hours, the supernatant was replaced by a new culture medium containing 10, 50, 100, 500, 1000 and 2000 ppm of MTA and MTA-SN suspensions and the cells were incubated under the culture conditions for 24, 48 and 72 hours. Each concentration was cultured three times in three wells and each raw of wells in each plate next to the different concentrations of MTA and MTA-SN of each well was considered as a control. After each study interval, the plates were retrieved from the incubator, the supernatant in each well was removed and 200 µL of the RPMI culture medium in association with 10 µL of MTT were added to each well. Then the plates were incubated at 37ºC for 3‒4 hours. In the next stage, the produced formazan product was dissolved by adding 100 µL of dimethyl sulfoxide solvent and the amount of the color produced was determined by an ELISA reader at a wavelength of 570 nm. Results The human dental pulp stem cells were treated with different concentrations of MTA and MTA-SN for 24, 48 and 72 hours to evaluate their biologic effects. The results of MTT assay are presented in 6 graphs. The viability of the human dental pulp stem cells after incubation with MTA and MTA-SN for 24, 48 and 72 hours. The hemolysis test was carried out to evaluate the hematologic compatibility of the samples at different concentrations. As shown in the figure below, there was no hemolysis at any of the concentrations. Calculations with the equation No. 1 showed that the percentage of hemolysis was <0.5%, consistent with the ISO/TR7406 (hemolysis <0.5%). Conclusion The results of the present in vitro study showed no toxicity of MTA and MTA-SN. In addition, an increase in the proliferation of cells, compared to the control cells, was observed over time, confirming the biocompatibility of the materials tested.