Cytotoxicity of a Self-etching Dentine Bonding Agent

Objective: The cytotoxicity of Clearfil Protect Bond (Kuraray) was evaluated using a mouse 3T3 cell culture model. The primer and the bond of this two bottle dentine bonding system were evaluated separately as well as the combination of the primer and bond. Methods: The cells were grown and sub-cultured using standard conditions. Each test sample was placed onto permeable membranes (10 for each sample), attached to reaction vials containing medium, and light-cured. Following a 24-hour incubation period during which time the medium was exposed to the test sample, the medium was transferred into three (96-wells/plate) plates containing the cultured cells. Cell viability was then compared to a similar number of controls using the MTT. Each experiment was done in triplicate. Results: The primer was found to be most cytotoxic showing a cell survival rate of about 30%. The bond was least toxic with a cell survival rate of about 91%. The combination of the primer and bond showed a cell survival rate of 34% (p<0.05 Kruskal-Wallis Multiple-Comparison Z-Value Test). Thus, the combination of the components MDPB + HEMA, present in the primer was more toxic than the combination of bis-GMA + HEMA components present in the bond. Conclusions: This dentine bonding agent releases sufficient components to interfere with cell viability in an in vitro culture model. The components MDPB and/or HEMA present in the primer may be the causative agents.