Comparison of cytotoxic effects of self-etching adhesive systems

Comparison of cytotoxic effects of self-etching adhesive systems

Objectives: The aim of this study was to compare the cytotoxic effects of self-etching primers/adhesives on fibroblasts by direct contact and dentin barrier tests.

Methods: Two self-etching primers; Clearfil SE Bond primer (CSE) and Clearfil Protect Bond primer (CPB), and four single-step self-etching adhesives; Clearfil Tri-S Bond (CTS), Reactmer Bond (RB), Adper Prompt (AP) and Prime Bond NT/NRC (PNT), were exemined. In direct contact tests, mouse fibroblasts L-929 cells were cultured in the presence of diluted solutions of each primer or adhesive (5 x 10^-1, 2 x 10^-1, 10^-1, 10^-2) for 24 h at 37˚C. For dentin barrier tests, each material was applied onto 0.5 or 1.5 mm thick human dentin disc assembled in a simple pulp chamber device, and incubated for 24 h at 37˚C to make the diffusive components contact with L-929 cells placed at the bottom of the chamber. The cytotoxic effects were assessed by MTT assay. The cell culture without application of any primers/adhesives served as the control for both tests. One way ANOVA and Tukey HSD tests were used for statistical analysys.

Results: The direct contact tests demonstrated that CSE or CPB were less toxic than the other materials at all concentrations (p<0.05). In the dentin barrier tests, the toxic effects of all materials were reduced as the increase in thickness of intervening dentin. CSE and CPB showed less cytotoxicity than the other adhesives (p<0.05) when applied to 0.5 mm-thick dentin, and CSE was the least toxic for the case of application to 1.5 mm-dentin (p<0.05).

Conclusion: By both direct contact and dentin barrier tests, CSE and CPB were found to be less toxic than the other adhesives, suggesting that the HEMA-based primers of two-step self-etching systems are more biocompatible compared with single-step self-etching adhesives.