Effect of Opalescence® bleaching gels on the elution of bulk-fill composite components

Objectives. Bleaching treatments can affect release of components from conventional composites. In this continuing study the influence of two different bleaching gels on the elution of bulk-fill composite components was investigated. Methods. The composites Tetric EvoCeram (R) Bulk Fill, QuiXFil (TM) and X-tra fil were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5 h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24 h and 7d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. Results. A total of 7 different elutable substances have been identified from the investigated composites after bleaching-treatment. Three of them were methacrylates: 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and trimethylolpropane trimethacrylate (TMPTMA). Compared to the unbleached controls an increase in elution after PF 15%-treatment of following compounds was found: HEMA (Tetric EvoCeram (R) Bulk Fill), TEGDMA (QuiXFil (TM), X-tra fil) and 4-N,N-dimethylaminobenzoic acid butyl ethoxy ester (DMABEE) (Tetric EvoCeram (R) Bulk Fill, QuiXFil (TM), X-tra fil). Following compounds showed a reduction in elution after PF 35%-treatment compared to controls: TEGDMA (QuiXFil (TM)) and DMABEE (Tetric EvoCeram (R) Bulk Fill). The highest concentration of HEMA was 0.22 mmol/l (Tetric EvoCeram (R) Bulk Fill, methanol, 7d, PF 15%), the highest concentration of TEGDMA was 0.3 mmol/l (X-tra fil, water, 7d, PF 15%) and the highest concentration of DMABEE was 0.05 mmol/l (QuiXFil (TM), water, 7d, PF 35%). Significance. PF 15% and PF 35% can lead to reduced and/or increased elution of some bulk-fill components, compared to unbleached bulk-fill composites. (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.