The Experts below are selected from a list of 1350 Experts worldwide ranked by ideXlab platform
Gottfried Schmalz - One of the best experts on this subject based on the ideXlab platform.
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bpa from Dental resin material where are we going with restorative and preventive Dental Biomaterials
Clinical Oral Investigations, 2014Co-Authors: Michel Goldberg, Sasha Dimitrovanakov, Gottfried SchmalzAbstract:Since a number of years, the question of the impact of BPA released from Dental resins and/or sealants (or other Dental materials) is open. These materials contain different monomers and many additives that are used to induce or inhibit the polymerization reaction. The monomers are mainly urethane dimethacrylate, BPA glycidyl dimethacrylate (Bis-GMA), its ethoxylated version (Bis-EMA), and BPA dimethacrylate (Bis-DMA). Comonomers such as triethylene glycol dimethacrylate are used to dilute the thick consistency and provide a higher degree of cure because of their relatively lower molecular weight [1]. BPA is used in the manufacturing process of Bis-GMA, Bis-EMA, and Bis-DMA or other similar molecules, and thus, minute amounts of BPA residuesmay be present in the final material. Interestingly, it has been shown that some patients treated with Bis-DMA containing materials present salivary and urinary BPA concentrations two to tenfold higher than control patients [2], which, however, decreased to almost normal after 24 h. For Bis-GMA materials, very small amounts of BPA could be detected in saliva and only neglectable amounts in urine, which also decreased 24 h after placement. It has been published that BPA may act as an endocrine disruptor (ED), thus being able to alter functions of the endocrine system and cause adverse health effects to an intact organism or its progeny (World Health Organization (WHO) definition 2002). EDs with an estrogenic activity have been proposed to be associated with estrogenic effects such as testicular dysgenesis, inducing testicular, prostate, and mammary gland cancers, impairing semen quality, diabetes, and obesity [3]. Some authors [3–5] claim that a series of diseases including cancer risks, type 2 diabetes, obesity, and developmental impairments are related to exposure towards BPA [3–5]. In human cross-sectional studies, BPA plasma or urine concentrations were reported to be associated among others with prostate dysplasias and abnormal birth weight [4]. A main problem in this context is the correct chemical analysis of BPA, the sensitivity of the analytical methods, and the question of BPA conjugation/glucoronization. Whereas the measurements in urine may be considered reliable, unconjugated BPA is apparently difficult to be measured in plasma because the sensitivity of the methods may not allow the measure the concentrations in the picogram per milliliter range. It is accepted that reported results in plasma/serum may be artifacts due to external contamination of the samples. Experimental studies in animals could not confirm results from reported observational studies in humans and showed general toxicity of BPA of doses above 5 mg/kg bw/day. Proliferation of mammary gland at doses of 400 μg/kg bw/day in monkeys [6] and behavioral effects in rodents at the same dose level. Although there are effects to be noted in in vitro studies on cell and tissue cultures and in vivo animal experiments, which may indicate adverse endocrine related effects due to BPA, it is still difficult to extrapolate these findings to the human clinical situation. Its precise mechanism of action is still not clear, as the signaling pathways seem to be dependent on the BPA concentrations. However, its functional interaction with estrogen receptors has been recently demonstrated and could explain at least in part its endocrine disrupting effects [4]. In the EU, USA, and Canada, BPA was banned from feeding bottles. M. Goldberg (*) : S. Dimitrova-Nakov INSERM UMR-S U747 (Equipe 5) & Faculte des Sciences Fondamentales et Biomedicales, Universite Paris Descartes, 45 rue des Saints Peres, 75270 Paris Cedex 06, France e-mail: mgoldberg.goldberg004@gmail.com
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BPA from Dental resin material: Where are we going with restorative and preventive Dental Biomaterials?
Clinical Oral Investigations, 2014Co-Authors: Michel Goldberg, Sasha Dimitrova-nakov, Gottfried SchmalzAbstract:The incidence and/or prevalence of health problems associated with endocrine-disruption have increased. Many chemicals have endocrine-disrupting properties, including bisphenol A, some organochlorines, polybrominated flame retardants, perfluorinated substances, alkylphenols, phthalates, pesticides, polycyclic aromatic hydrocarbons, alkylphenols, solvents, and some household products including some cleaning products, air fresheners, hair dyes, cosmetics, and sunscreens. Even some metals were shown to have endocrine-disrupting properties. Many observations suggesting that endocrine disruptors do contribute to cancer, diabetes, obesity, the metabolic syndrome, and infertility are listed in this paper. An overview is presented of mechanisms contributing to endocrine disruption. Endocrine disruptors can act through classical nuclear receptors, but also through estrogen-related receptors, membrane-bound estrogen-receptors, and interaction with targets in the cytosol resulting in activation of the Src/Ras/Erk pathway or modulation of nitric oxide. In addition, changes in metabolism of endogenous hormones, cross-talk between genomic and nongenomic pathways, cross talk with estrogen receptors after binding on other receptors, interference with feedback regulation and neuroendocrine cells, changes in DNA methylation or histone modifications, and genomic instability by interference with the spindle figure can play a role. Also it was found that effects of receptor activation can differ in function of the ligand.
Shutao Wang - One of the best experts on this subject based on the ideXlab platform.
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Antibacterial Property of a Polyethylene Glycol-Grafted Dental Material
ACS Applied Materials & Interfaces, 2017Co-Authors: Liying Peng, Li Chang, Shutao WangAbstract:Dental materials often cause bacterial adhesion and promote bacterial biofilm formation, which brings a series of long-standing and significant problems in oral health. However, the current development of antibacterial research in Dental devices is limited by the lack of materials endowed with good antibacterial properties against oral bacteria. Here, we present a new strategy for reducing the initial adhesion of bacterial on Dental Biomaterials by chemically bonding long-chain polyethylene glycol. Our work represents an important step toward solving the problem of bacterial accumulation on Dental devices.
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Antibacterial Property of a Polyethylene Glycol-Grafted Dental Material
ACS Applied Materials and Interfaces, 2017Co-Authors: Liying Peng, Jiuxiang Lin, Hongliang Liu, Bing Han, Xi Liu, Li Chang, Shutao WangAbstract:© 2017 American Chemical Society. Dental materials often cause bacterial adhesion and promote bacterial biofilm formation, which brings a series of long-standing and significant problems in oral health. However, the current development of antibacterial research in Dental devices is limited by the lack of materials endowed with good antibacterial properties against oral bacteria. Here, we present a new strategy for reducing the initial adhesion of bacterial on Dental Biomaterials by chemically bonding long-chain polyethylene glycol. Our work represents an important step toward solving the problem of bacterial accumulation on Dental devices.
Michel Goldberg - One of the best experts on this subject based on the ideXlab platform.
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bpa from Dental resin material where are we going with restorative and preventive Dental Biomaterials
Clinical Oral Investigations, 2014Co-Authors: Michel Goldberg, Sasha Dimitrovanakov, Gottfried SchmalzAbstract:Since a number of years, the question of the impact of BPA released from Dental resins and/or sealants (or other Dental materials) is open. These materials contain different monomers and many additives that are used to induce or inhibit the polymerization reaction. The monomers are mainly urethane dimethacrylate, BPA glycidyl dimethacrylate (Bis-GMA), its ethoxylated version (Bis-EMA), and BPA dimethacrylate (Bis-DMA). Comonomers such as triethylene glycol dimethacrylate are used to dilute the thick consistency and provide a higher degree of cure because of their relatively lower molecular weight [1]. BPA is used in the manufacturing process of Bis-GMA, Bis-EMA, and Bis-DMA or other similar molecules, and thus, minute amounts of BPA residuesmay be present in the final material. Interestingly, it has been shown that some patients treated with Bis-DMA containing materials present salivary and urinary BPA concentrations two to tenfold higher than control patients [2], which, however, decreased to almost normal after 24 h. For Bis-GMA materials, very small amounts of BPA could be detected in saliva and only neglectable amounts in urine, which also decreased 24 h after placement. It has been published that BPA may act as an endocrine disruptor (ED), thus being able to alter functions of the endocrine system and cause adverse health effects to an intact organism or its progeny (World Health Organization (WHO) definition 2002). EDs with an estrogenic activity have been proposed to be associated with estrogenic effects such as testicular dysgenesis, inducing testicular, prostate, and mammary gland cancers, impairing semen quality, diabetes, and obesity [3]. Some authors [3–5] claim that a series of diseases including cancer risks, type 2 diabetes, obesity, and developmental impairments are related to exposure towards BPA [3–5]. In human cross-sectional studies, BPA plasma or urine concentrations were reported to be associated among others with prostate dysplasias and abnormal birth weight [4]. A main problem in this context is the correct chemical analysis of BPA, the sensitivity of the analytical methods, and the question of BPA conjugation/glucoronization. Whereas the measurements in urine may be considered reliable, unconjugated BPA is apparently difficult to be measured in plasma because the sensitivity of the methods may not allow the measure the concentrations in the picogram per milliliter range. It is accepted that reported results in plasma/serum may be artifacts due to external contamination of the samples. Experimental studies in animals could not confirm results from reported observational studies in humans and showed general toxicity of BPA of doses above 5 mg/kg bw/day. Proliferation of mammary gland at doses of 400 μg/kg bw/day in monkeys [6] and behavioral effects in rodents at the same dose level. Although there are effects to be noted in in vitro studies on cell and tissue cultures and in vivo animal experiments, which may indicate adverse endocrine related effects due to BPA, it is still difficult to extrapolate these findings to the human clinical situation. Its precise mechanism of action is still not clear, as the signaling pathways seem to be dependent on the BPA concentrations. However, its functional interaction with estrogen receptors has been recently demonstrated and could explain at least in part its endocrine disrupting effects [4]. In the EU, USA, and Canada, BPA was banned from feeding bottles. M. Goldberg (*) : S. Dimitrova-Nakov INSERM UMR-S U747 (Equipe 5) & Faculte des Sciences Fondamentales et Biomedicales, Universite Paris Descartes, 45 rue des Saints Peres, 75270 Paris Cedex 06, France e-mail: mgoldberg.goldberg004@gmail.com
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BPA from Dental resin material: Where are we going with restorative and preventive Dental Biomaterials?
Clinical Oral Investigations, 2014Co-Authors: Michel Goldberg, Sasha Dimitrova-nakov, Gottfried SchmalzAbstract:The incidence and/or prevalence of health problems associated with endocrine-disruption have increased. Many chemicals have endocrine-disrupting properties, including bisphenol A, some organochlorines, polybrominated flame retardants, perfluorinated substances, alkylphenols, phthalates, pesticides, polycyclic aromatic hydrocarbons, alkylphenols, solvents, and some household products including some cleaning products, air fresheners, hair dyes, cosmetics, and sunscreens. Even some metals were shown to have endocrine-disrupting properties. Many observations suggesting that endocrine disruptors do contribute to cancer, diabetes, obesity, the metabolic syndrome, and infertility are listed in this paper. An overview is presented of mechanisms contributing to endocrine disruption. Endocrine disruptors can act through classical nuclear receptors, but also through estrogen-related receptors, membrane-bound estrogen-receptors, and interaction with targets in the cytosol resulting in activation of the Src/Ras/Erk pathway or modulation of nitric oxide. In addition, changes in metabolism of endogenous hormones, cross-talk between genomic and nongenomic pathways, cross talk with estrogen receptors after binding on other receptors, interference with feedback regulation and neuroendocrine cells, changes in DNA methylation or histone modifications, and genomic instability by interference with the spindle figure can play a role. Also it was found that effects of receptor activation can differ in function of the ligand.
Liying Peng - One of the best experts on this subject based on the ideXlab platform.
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Antibacterial Property of a Polyethylene Glycol-Grafted Dental Material
ACS Applied Materials & Interfaces, 2017Co-Authors: Liying Peng, Li Chang, Shutao WangAbstract:Dental materials often cause bacterial adhesion and promote bacterial biofilm formation, which brings a series of long-standing and significant problems in oral health. However, the current development of antibacterial research in Dental devices is limited by the lack of materials endowed with good antibacterial properties against oral bacteria. Here, we present a new strategy for reducing the initial adhesion of bacterial on Dental Biomaterials by chemically bonding long-chain polyethylene glycol. Our work represents an important step toward solving the problem of bacterial accumulation on Dental devices.
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Antibacterial Property of a Polyethylene Glycol-Grafted Dental Material
ACS Applied Materials and Interfaces, 2017Co-Authors: Liying Peng, Jiuxiang Lin, Hongliang Liu, Bing Han, Xi Liu, Li Chang, Shutao WangAbstract:© 2017 American Chemical Society. Dental materials often cause bacterial adhesion and promote bacterial biofilm formation, which brings a series of long-standing and significant problems in oral health. However, the current development of antibacterial research in Dental devices is limited by the lack of materials endowed with good antibacterial properties against oral bacteria. Here, we present a new strategy for reducing the initial adhesion of bacterial on Dental Biomaterials by chemically bonding long-chain polyethylene glycol. Our work represents an important step toward solving the problem of bacterial accumulation on Dental devices.
Jon E. Dahl - One of the best experts on this subject based on the ideXlab platform.
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Filler particles used in Dental Biomaterials induce production and release of inflammatory mediatorsin vitro
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2020Co-Authors: Vibeke E. Ansteinsson, Jan Tore Samuelsen, Jon E. DahlAbstract:Dental polymer-based composite materials are complex materials consisting of several components, the main components being filler particles (inorganic component) and polymer matrix (organic component). The organic component consists of monomers that usually are polymerized upon activation by visible light illumination.The polymerization process is never complete, and leakage of unreacted methacrylate monomers occurs during clinical service. Degradation processes may weaken the bond between the fillers and the matrix, leading to release of fillers particles and ions in addition to the organic components. Clinical handling during placement and finishing has been shown to cause release of particulate matter to the air in Dental clinics, which could be followed by exposure to tissue and saliva of the patients. Thus, both Dental personnel and patients could be exposed to components of polymer-based Dental materials.The main objective of the thesis was to characterize the toxic potential of selected inorganic filler particles (barium glass particles and silica particles) and methacrylates (HEMA, TEGDMA, BisGMA, GDMA, MMA) used in Dental composite filling materials. The results showed that both nano- and micro-sized filler particles could modulate the release of inflammatory mediators in vitro. The methacrylates investigated induced cytotoxicity, but the potency and the mechanism involved seemed to differ between the methacrylates. HEMA was found to induce apoptosis and DNA damage followed by activation of DNA damage response. To address possible exposure to multiple components of polymer-based Dental composite materials the effect of co-exposure to components was studied. An additive inflammatory response was observed with particles and TEGDMA co-exposure.Studies on the mechanisms of possible adverse biological responses to substances released from polymer-based Dental materials could contribute to safer Dental materials.
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filler particles used in Dental Biomaterials induce production and release of inflammatory mediators in vitro
Journal of Biomedical Materials Research Part B, 2009Co-Authors: Vibeke E. Ansteinsson, Jan Tore Samuelsen, Jon E. DahlAbstract:Although Dental composites are in extensive use today, little is known about the biological effects of the filler particles. As composite materials are gradually broken down in the aggressive environment of the oral cavity, the filler particles may leak and induce toxic effects on the surrounding tissue and cells. The aim of this study was to elucidate possible adverse biological effects of commonly used Dental filler particles; bariumaluminiumsilica (BaAlSi) and bariumaluminiumfluorosilica (BaAlFSi) with mean size of 1 μm. BEAS-2B cells were used as a model system. Particle morphology, mean particle size in solution, and particle surface charge were determined by scanning electron microscopy and Malvern zetasizer technology, respectively. Enzyme-linked immunosorbent assay was used to detect secretion of cytokine and chemokine (IL-8 and IL-6) and quantitative PCR for detection of gene activity. Both types of particle increased the release of IL-6 and IL-8 in a dose-dependent manner. BaAlFSi particles induced a more marked IL-8 response compared to BaAlSi particles, whereas no significant difference was observed for the IL-6 response. Mechanistic studies using specific inhibitors and activators indicated that cyclic AMP-dependent protein kinase A is partly involved in the observed IL-8 response. In conclusion, we consider Dental filler particles to have potential to induce adverse biological response in cell cultures. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
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Responses of the pulp–dentin organ to Dental restorative Biomaterials
Endodontic Topics, 2007Co-Authors: Jon E. Dahl, Dag ØrstavikAbstract:Placement of a restorative material in dentin produces the possibility of pulpal injury. In vitro studies have shown that the constituents of Dental Biomaterials have toxic potentials. In the clinical setting, there may be an immediate reaction of the pulp to, for example, acid etching and to the placement of a bonding agent; however, in most cases the remaining dentin serves as protection against long-term or permanent damage to the pulp. Important factors for long-term pulpal outcome are microleakage with possible bacterial penetration and leakage products from restorative materials. Both factors are influenced by the cavity depth, i.e., the remaining thickness of sound dentin. Received 13 February 2009; accepted 29 August 2009.