Cytotoxicity of a Dentine Bonding Agent

Aim: The objective of this study was to investigate the effect of concentration of a dentine bonding agent on the cytotoxicity of a mouse fibroblast cell-line (3T3) and four different human pulp fibroblast cell-lines. Methods: The cells were grown and subcultured using standard conditions. For the testing of the cytotoxicity of the bonding agent (Prime & Bond NT) it was extracted with DMEM medium and the different cell-lines were exposed to the extraction. The MTT assay was used to establish the number of viable cells. Results: For all 5 pairs (control vs test sample) of cell-lines for 4 µl bonding agent, the mouse and only two of the four human cell-lines showed a statistical significant difference (p < 0.05; Mann-Whitney) due to the cytotoxicity of the bonding agent. However, all 5 pairs showed significant differences (p < 0.05) at the 8 µl concentration level. To investigate the relative effect of concentration (4 µl compared to 8 µl) of Prime & Bond NT on the cytotoxicity of these 5 cell-lines, the Kruskal-Wallis Multiple-Comparison test was used on the standardized medians. Statistically significant differences (p < 0.05) were found for various cell-lines between both concentration levels. In general, the tested bonding agent, at a higher concentration level, has an increased cytotoxic effect on all 5 cell-lines. On average 69% (median) of 3T3 cells stayed viable with 4 µl (0.94cm2/ml) bonding agent and 61% when 8 µl was used. For the pulp cells the percentages were between 91% and 72% for 4 µl and between 77% and 24% for 8 µl. Conclusion: These findings indicated that the bonding agent Prime and Bond NT was cytotoxic and that different human pulp fibroblast cell-lines should be used and that the higher concentration range of that suggested by the ANSI/ADA document (2000, Revision) should be used.