The effect of glutathione on 2-hydroxyethylmethacrylate cytotoxicity and on resin-dentine bond strength

Aim: To evaluate the influence of reduced glutathione (GSH) application on 2-hydroxyethylmethacrylate (HEMA) cytotoxicity on rat pulpal cells and evaluate the effect of etched-dentine treatment with GSH on the immediate microtensile bond strength (μTBS) of etch-and-rinse adhesive. Methodology: The cytotoxicity of 10mmolL^-1 HEMA, 10mmolL^-1 HEMA+1mmolL^-1 GSH, 10 mmolL^-1 HEMA+5mmolL^-1 GSH and 10mmol L^-1 HEMA+10mmolL^-1 GSH was compared (6h and 24h). Cells viability was measured by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, followed by morphological observation of cells. Etched-dentine surfaces were rinsed and treated with one of the following solutions: 2% GSH, 5% GSH or 10% GSH, bonded with Adper Single Bond Plus (3M, ESPE, St. Paul, MN, USA) and restored with resin composite. The control group received no GSH treatment. After 1day of water-storage at 37°C, the specimens were subjected to μTBS testing. Cytotoxicity and μTBS data were analysed by one-way anova and Tukey post hoc tests (P<0.05). Results: There were significant differences between the groups. HEMA elicited a remarkable toxic effect. 10mmolL^-1 GSH prevented HEMA-induced damage at both exposure times. Whilst 5mmolL^-1 GSH lost its protective effect at 24-h exposure time and 1mmolL^-1 GSH showed no protective effect at both exposure times, GSH had no significant effect on the immediate μTBS; however, 5% GSH had higher bond strength value when compared to 10% GSH (P=0.003). Conclusion: Controlled concentrations of GSH had a protective effect against HEMA cytotoxicity. GSH had neither positive nor negative influence on μTBS.