In vitro cytotoxicity of one-step dentin bonding systems

The cytotoxicity of resinous monomers may vary on mixing, calling into question the cytotoxicity of the new dentin bonding agents that are mixed in a single vial. The cytotoxicity of fourth and fifth generation dentin bonding agents was compared in vitro. All-Bond 2, One-Step, Scotchbond Multi-Purpose, Scotchbond One, Syntac, Syntac Single Component, Tenure, and Tenure Quick were tested uncured. The cytotoxicity of several dilutions of fourth generation dentin primer, dentin bonding agent, dentin primer + dentin bonding agent, and fifth generation single component products diluted at 10(-1) to 10(-8) in culture medium was recorded with a MTT assay on L929 fibroblasts. Only one synergistic (increased cytotoxicity after mixing primer and bonding agent) cytotoxic effect was observed with Tenure at 10(-5) dilution. An antagonistic effect (decreased cytotoxicity after mixing primer and bonding agent) was observed with All-Bond 2 between 10(-4) and 10(-8) dilutions. Scotchbond and Syntac fifth generation dentin bonding agents were less cytotoxic than their fourth generation counterparts. All-Bond and Tenure fifth generation dentin bonding agents were more cytotoxic than their fourth generation counterparts only in low dilutions. Clinical studies should confirm these good results, because no dramatic synergistic cytotoxic effect could be detected.