In Vitro Evaluation Of The Cytotoxicity Of Bonding Resin Material

Objective:To evaluate the cytotoxicity of ParaCore resin/ParaBond dentin adhesive in vitro which are used as root filling materials.Material and methods:Four kinds of materials(ParaCore bonding resin,ParaBond dentin adhesive,gutta-percha,AH Plus endodontics sealer)were selected and set in incubator at 37 ?for 1 day and 7 days after preparation according to the instructions of manufacturers.The Four solutions of 100%,50%,25%,12.5% material concentrations were diluted respectively for every material and then were incubated with the L-929 permanent fibroblasts cell lines of mouse for 24 hours.The cytotoxicity of the materials was assessed by relative growth rate using the MTT assay method.The relative growth rate(RGR)was measured with a Multiskan EX spectrophotometer at 490 nm length.Data were statistically analyzed.Results:1.Morphological observation of L-929 fibroblasts: there was no significant difference about the quantity and morphology of the cells between the fresh and aged group of ParaCore,ParaBond and gutta percha whereas it was significantly different between the fresh and aged group of AH Plus.The cells of ParaCore group were normal in shape,vigorous,fusiform or polygonal,and cell refractivity was strong.The intracellular structure was clear,and circular dividing cells could be seen.The cells in ParaBond and gutta-percha group were round and there were many granular substances in the cytoplasm and the cells were disintegrated.The cells of the fresh group of AH Plus were as same as those of ParaBond and gutta-percha group.However,the cells in the aged group were normal in morphology and the amount of cells increased.2.In four concentration solutions of fresh samples,the relative growth rate of cells in ParaCore group was significantly higher than gutta-percha group(P<0.05)and the relative growth rate of ParaBond group was significantly lower than AH Plus group(P<0.05).In fresh samples,the greater the concentration,the lower the relative growth rate.The relative growth rate differences between every two groups of other three materials except gutta-percha group were statistically significant(P<0.05).3.In four concentrations solutions of aged samples,except the 25% concentration group,The relative growth rate of ParaCore group was significantly higher than that of gutta-percha group in the other three concentration groups(P<0.05).The relative growth rate of ParaBond group was significantly lower than that of AH Plus group in the 100% and 50% concentration groups(P<0.05).In aged samples,the greater the concentration,the lower the relative growth rate.Except the AH Plus group,the differences of the four concentrations of the other materials were statistically significant(P<0.05).Further analysis with LSD-t test revealed that the RGR of the 100% concentration of ParaCore group was significantly lower than the 12.5% concentration and the RGR of the 50% concentration of ParaCore group was significantly lower than the 12.5% concentration(P<0.05).Except the RGR of the 50% concentration of gutta-percha group was significantly lower than the 25% concentration and the RGR of the 25% concentration of gutta-percha group was significantly lower than the 12.5% concentration,the RGR differences between every two groups of other concentrations of gutta-percha group were statistically significant(P<0.05).Except the RGR of the 25% concentration of ParaBond group was significantly lower than the 12.5% concentration,the RGR differences between every two groups of other concentrations of ParaBond group were statistically significant(P<0.05).4.With the increase of setting time,the relative growth rate increased in all materials.There was statistical significance between fresh and aged groups of all materials except gutta-percha group(P<0.05).Conclusions:The ParaCore has a lower cytotoxicity compared with gutta-percha and the ParaBond has a greater cytotoxicity than AH Plus.The concentration had an influence on the cytotoxicity of all tested materials.Except gutta-percha,the longer setting time,the less the cytotoxicity.