Biocompatibility of self-adhesive resin cement with fibroblast cells

Abstract

Statement of problem: Dental cements that release monomers that negatively impact adjacent oral soft tissues may adversely affect clinical outcomes. However, in vitro studies evaluating the cytotoxic and genotoxic potential of substances released from dental cements are lacking.

Purpose: The purpose of this in vitro study was to define and compare the cytotoxicity and genotoxicity of the eluates of a self-adhesive resin cement (RelyX Unicem 2 Automix) autopolymerized and light polymerized with 2 other types of luting cements: a glass ionomer cement (Ketac Cem Easymix) and a resin-modified glass ionomer cement (Ketac Cem Plus).

Material and methods: The eluates were prepared, and 3T3 mouse fibroblast cells were exposed for 24 hours to serial eluate dilutions of the 3 types of cement. Cytotoxicity was determined by using a cell viability assessment through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays. Genotoxic effects were determined by using the cytokinesis-block micronucleus assay.

Results: Cell viability was higher in the presence of the glass ionomer cement eluate than of the resin-modified glass ionomer cement and resin cement eluates. A pronounced decrease in viability was found when the cells were exposed to undiluted samples of resin-modified glass ionomer cement (around 50%) or resin cement (around 80% to 90%). No significant difference in cell viability was found between autopolymerized and light-polymerized resin cements. All cements induced a dose-dependent response of mononucleated cell formation. However, only the resin cements showed double strand breaks significant differences in the deoxyribonucleic acid (DNA) molecules against the basal DNA lesions that occurred spontaneously.

Conclusions: The glass ionomer cement was not found to be cytotoxic or genotoxic, whereas the eluates derived from the resin-modified glass ionomer cement and resin cement, independently of the polymerization method, were cytotoxic in fibroblast cells. Maximum cytotoxicity was observed in the presence of resin cement, which also showed genotoxicity, independently of being light polymerized.