Cytotoxicity evaluation of dental resin composites and their flowable derivatives

The release of components from dental composite into surrounding tissue may cause an adverse tissue reaction. Thus, this study investigated the cytotoxicity of three types of dental composites with their flowable derivatives and determined the compounds released from these materials by high-performance liquid chromatography (HPLC) analysis. Fifteen specimens from each composite (Admira, Z250, Tetric Ceram) with fifteen of their flowables (Admira Flow, Tetric Flow, Feltik Flow) were prepared in the form of discs and divided into two groups of 10 and 5 for each material. The first group (10 discs) was used to evaluate the cytotoxicity of the material on balb/c 3T3 fibroblasts by measuring cellular metabolic activity (3{4,5-dimethylthiazol-2-yl}-2,5-diphenyltetrazolium bromide [MTT] assay) relative to Teflon controls, while the second group (5 discs) was used to determine the leached components from each material into culture medium by HPLC analysis. The results revealed that Z250 and Tetric Ceram were less cytotoxic than their flowable derivatives. However, the ormocer, Admira, was significantly more cytotoxic than Admira Flow. Among the standard composites, Tetric Ceram was the least cytotoxic and Admira the most. Furthermore, Tetric flow was the most cytotoxic and Admira flow was significantly the least cytotoxic among the flowable materials tested. HPLC analysis revealed bisphenol A glycerolate dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) in the eluates of all the materials, while urethane dimethacrylate (UDMA) was present in all eluates except that of Feltik Flow. In conclusion, the flowable derivatives are more cytotoxic than the traditional composites whereas the ormocer Admira Flow is less cytotoxic than the Admira composite.