Cytotoxicity Comparison of Harvard Zinc Phosphate Cement Versus Panavia F2 and Rely X Plus Resin Cements on Rat L929-fibroblasts

Objective: Resin cements, regardless of their biocompatibility, have been widely used inrestorative dentistry during the recent years. These cements contain hydroxy ethyl methacrylate(HEMA) molecules which are claimed to penetrate into dentinal tubules and mayaffect dental pulp. Since tooth preparation for metal ceramic restorations involves a largesurface of the tooth, cytotoxicity of these cements would be more important in fixed prosthodontictreatments. The purpose of this study was to compare the cytotoxicity of tworesin cements (Panavia F2 and Rely X Plus) versus zinc phosphate cement (Harvard)using rat L929-fibroblasts in vitro.Materials and Methods: In this experimental study, ninety hollow glass cylinders (internaldiameter 5-mm, height 2-mm) were made and divided into three groups. Each group wasfilled with one of three experimental cements; Harvard Zinc Phosphate cement, PanaviaF2 resin cement and Rely X Plus resin cement. L929- Fibroblast were passaged and subsequentlycultured in 6-well plates of 5×105 cells each. The culture medium was RPMI_1640. All samples were incubated in CO2. Using enzyme-linked immune-sorbent assay(ELISA) and (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay,the cytotoxicity of the cements was investigated at 1 hour, 24 hours and one week post exposure.Statistical analyses were performed via two-way ANOVA and honestly significantdifference (HSD) Tukey tests.Results: This study revealed significant differences between the three cements at the differenttime intervals. Harvard cement displayed the greatest cytotoxicity at all three intervals.After 1 hour Panavia F2 showed the next greatest cytotoxicity, but after 24-hours and oneweekintervals Rely X Plus showed the next greatest cytotoxicity. The results further showedthat cytotoxicity decreased significantly in the Panavia F2 group with time (p<0.005), cytotoxicityincreased significantly in the Rely X Plus group with time (p<0.001), and the Harvardcement group failed to showed no noticeable change in cytotoxicity with time.Conclusion: Although this study has limitations, it provides evidence that Harvard zincphosphate cement is the most cytotoxic product and Panavia F2 appears to be the leastcytotoxic cement over time