Cytotoxicity of liquids and powders of chemically different dental materials evaluated using dimethylthiazol diphenyltetrazolium and neutral red tests

Abstract

The purpose of this study was to assess and compare the cytotoxicity of liquid and powder components of chemically different dental materials using 2 basic unspecific cell culture methods. Three chemically cured glass ionomers (Fuji II, Lining cement, and Ketac Silver), 1 light-cured glass ionomer (Fuji II LC), and 2 chemically cured acrylates (Swedon and Super Bond) were tested. The liquids were diluted 1:10 in cell culture medium. The liquids from chemically cured acrylates were further diluted 1:100, 1:1000, and 1:10000. Extracts were made by incubating the powders in cell culture medium for 24 h at 37°C according to the ISO standard 10993-12. The cytotoxicity was assessed in transformed mouse fibroblasts (L-929) using two viability assays, dimethylthiazol diphenyltetrazolium (MTT) and neutral red (NR). Severe cytotoxicity was observed when testing powder extracts of Swedon, Fuji II, and Lining cement, whereas powder extracts of Ketac Silver, Fuji LC, and Super Bond induced slight to non-cytotoxicity. All of the 1:10 liquid dilutions were severely cytotoxic in the MTT assay. In the NR assay, however, four 10% dilutions were severely cytotoxic and 4 moderately cytotoxic. Further dilution of the liquids of the chemically cured acrylates reduced the toxicity, while the Super Bond catalyst was severely cytotoxic even as the 1:100 dilutions.