Cytotoxicity of Dental Adhesives on Established Cell Lines

Dental adhesives are designed to produce a hermetic seal between resin materials and tooth structure. Several components of dental adhesives may exert adverse effects to vital tissues. The use of cell lines and semi-automatic methods for estimating cell numbers is implicated in material's cytotoxicity testing. Objectives: The purpose of the present study was to evaluate in vitro the cytotoxic effect of four dentin adhesive systems on two established cell lines. Methods: The tested adhesive systems were: Admira (VOCO), Clearfil Liner Bond 2V (Kuraray), Nano-Bond (Jeneric/Pentron), GC Bond (GC Corporation). Two established cell lines were used: rat pulp cells (RPC-C2A) and human fibroblasts (MRC5). The cells were grown as monolayer at standard culture conditions (37°C, 5% CO2 and 100% relative humidity). The culture medium was Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum and antibiotics. Cells were inoculated at multiwell plates and left overnight to resume exponential growth. Set specimens from the dental adhesives were eluted with culture medium and the sterile filtrated extracted medium was used as experimental material. Cell survival was estimated after 24 and 48 hours of exposure by means of the modified sulphorodamine B staining assay. Results were expressed as survival fraction. Experiments were performed in sixplicates and repeated at least twice. The data were analyzed by one way analysis of variance (ANOVA) and Post Hoc test (p<0.05). Results: The tested adhesive systems caused reduction in cell number in time-dependent manner. Nano-Bond was the least toxic agent and Admira was the most toxic agent. Conclusions: All tested dental adhesives caused cytotoxic reactions in both cell lines. The degree of cytotoxicity depended on the materials tested.