The influence of methodology on the comparison of cytotoxicity of total-etch and self-etch adhesive systems

•Both, etch-and-rinse and self-etching adhesives, were cytotoxic under the standardized test.•Cell viability for self-etching adhesives was increased in the dentin-barrier model.•Clearfill SE Bond was identified as non-cytotoxic in the dentin-barrier model.•High levels of cytokines found after using Adper Scotchbond, Optibond S and Single Bond Universal. The present study aimed to compare the in vitro cytocompatibility of two etch-and-rinse (Adper Scothbond, Optibond) and two self-etch (Clearfill SE Bond and Single Bond Universal) dental adhesives through a dentin-barrier model with human pulp fibroblasts. Human fibroblasts were placed on a plastic device containing 500μm human dentin discs treated with each adhesive or without treatment (control). Other groups were directly exposed to media conditioned with adhesive samples according to ISO 10993-5:2009. After 24h exposure, cell viability was assessed by XTT, and released inflammatory mediators were detected with a multiparametric immunoassay. The standardized test without barrier indicated both etch-and-rinse adhesives and self-etch as cytotoxic, promoting viabilities under 70% of the control group (p