Effect of hydrogen peroxide on the three-dimensional polymer network in composites

摘要

Objectives. Less data are available about the effects of hydrogen peroxide on the three-dimensional polymer network of polymerized composites. Therefore the study was performed to test the effects of hydrogen peroxide on the three-dimensional polymer network in composites. Methods. Polymerized specimens from Tetric Flow®, Tetric Ceram® and Filtek™ Supreme XT were bleached with Opalescence® PF 15% for 5 h or PF 35% for 0.5 h, respectively, and then stored in methanol for 1 d and 7 d. Controls were unbleached specimens. The eluates were analyzed by gas chromatography/mass spectrometry. Results. More methacrylic acid (MAA), bisphenol-A (BPA), ethoxylated bisphenol-A-dimethacrylate (BisEMA), hydroquinone monomethyl ether (HQME), 1,10-decanediol dimethacrylate (DDDMA) and/or triethylene glycol dimethacrylate (TEGDMA) were eluted from bleached specimens compared with non bleached controls (1 d). The highest DDDMA amount of 419.8 μ.mol/1 was found in the eluates after 7 d in Tetric Flow" specimens treated with PF 15. The highest HQME amount of 159.6 μ.mol/1 was found in eluates from Tetric Ceram® specimens treated with PF after 7d. The highest TEGDMA amount of 178.7 p.mol/1 was found in eluates from Filtek™ Supreme XT specimens treated with PF 35 after 7 d. Significance. Bleaching with hydrogen peroxide has an effect on the three-dimensional polymer network in polymerized composites leading to an increase in the release of unpoly-merized monomers, additives and unspecific oxidative products.