Cytotoxicity of substances leached or dissolved from self-etching bonding systems

Objectives: Since new bonding systems are often been released, the purpose of this study was to evaluate the in vitro cytotoxicity of substances leached from self-etching bonding systems on human dental pulp fibroblasts. Methods: The substances were applied to cell cultures in conditioned media. The experimental groups were: GI (control; n=4) – cultures treated with fresh medium; GII (n=4) – cultures treated with calcium hydroxide powder; GIII (n=4) – cultures treated with Single Bond®; GIV (n=4) – cultures treated with Clearfill Protect Bond® primer; GV (n=4) – cultures treated with Clearfill Protect Bond® resin; GVI (n=4) – cultures treated with AdheSE® primer; GVII (n=4) – cultures treated with AdheSE® resin. The media were conditioned by placing the crude materials in contact with fresh culture medium for 1 hour. The cell viability was achieved by measuring MTT reduction 24 h after the contact with the substances. Data were compared by the Kruskal-Wallisx test (p<0.05). Results: The cultures that present the significantly highest numbers of viable cells were those of groups II, V, VI and VII, which were similar to those of control cultures (group I). The significantly smallest numbers of viable cells were observed at cultures of groups III and IV. Conclusion: Substances leached or dissolved from the conventional bonding system (Single Bond ®) as well as from the Clearfill Protect Bond® primer are cytotoxic to human dental pulp cells in culture. On the other hand, Ca(OH)2, Clearfill Protect Bond® resin, and both AdheSE® primer and resin do not cause cell death, thus are biocompatible.