Browsing by Subject "resin composites"

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    A NOVEL ANTIBACTERIAL RESIN COMPOSITE CONTAINING QUATERNARY AMMONIUM SALTS
    (Office of the Vice Chancellor for Research, 2012-04-13) Howard, Leah; Weng, Yiming; Guo, Xia; Chong, Voon Joe; Gregory, Richard L.; Xie, Dong
    Objectives: The objective of this study was to synthesize new quater-nary ammonium bromide (QAB)-containing oligomers, incorporate them to dental resin composites, and evaluate the effects of these new oligo-mers on the mechanical strength and antibacterial activity of the formed composites. Methods: The novel quaternary ammonium bromide (QAB)-containing oligomers were synthesized and applied for developing an an-tibacterial resin composite. Compressive strength (CS) and S. mutans (an oral bacteria strain) viability were used to evaluate the mechanical strength and antibacterial activity of the formed composites. Results: All the QAB-modified resin composites showed significant antibacterial activi-ty and mechanical strength reduction. Increasing chain length and loading significantly enhanced the antibacterial activity but dramatically reduced the CS. The 30-day aging study showed that the incorporation of the QAB accelerated the degradation of the composite, suggesting that the QAB may not be well suitable for development of antibacterial dental resin composites or at least the QAB loading should be well controlled, unlike its use in dental glass-ionomer cements. Conclusions: The work in this study is beneficial and valuable to those who are interested in studying antibacterial dental resin composites.
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    Tegdma induction of apoptotic proteins in pulp fibroblasts
    (2011) Batarseh, Ghada; Gregson, Karen; Windsor, L. Jack; Cochran, Michael A. (Michael Alan), 1944-; Platt, Jeffrey A., 1958-; Vail, Mychel Marapagal, 1969-; Cook, Norman Blaine, 1954-
    Monomers like triethylene glycol dimethacrylate (TEGDMA) leach from dental composites and adhesives due to incomplete polymerization or polymer degradation. The release of these monomers causes a variety of reactions that can lead to cell death. This death can be either necrotic, which is characterized mainly by inflammation and injury to the surrounding tissues, or apoptotic, which elicits little inflammatory responses, if any at all. TEGDMA-induced apoptosis in human pulp has been reported recently. However, the molecular mechanisms and the apoptotic (pro and anti) proteins involved in this process remain unclear. The objective of this study was to determine the apoptotic proteins expressed or suppressed during TEGDMA-induced apoptosis. Human pulp fibroblasts (HPFs) were incubated for 24 hours with different TEGDMA concentrations (0.125-1.0 mM). Cytotoxicity was determined using the cytotoxicity Detection KitPLUS (Roche Applied Science, Mannheim, Germany). TEGDMA was shown to cause cell cytotoxicity at concentrations of 0.50 mM and up. The highest concentration with no significant cytotoxicity was used. Cells were incubated with or without 0.25 mM TEGDMA for 6 h and 24 h. Cell lysates were then prepared and the protein concentrations determined using the Bradford protein assay. A Human Apoptosis Array kit (Bio-Rad Hercules, CA ) was utilized to detect the relative levels of 43 apoptotic proteins. The results of this study showed statistically significant increases of multiple examined pro-apoptotic proteins. The anti-apoptotic proteins were also altered. Pro-apoptotic proteins involved in the intrinsic and extrinsic apoptotic pathways were increased significantly. The results indicated that TEGDMA has effects on both the extrinsic and intrinsic apoptotic pathways.