Papers by Author: Lambrini Papadopoulou

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Authors: Ourania Menti Goudouri, Eleana Kontonasaki, Nikolaos Kantiranis, Xanthippi Chatzistavrou, Lambrini Papadopoulou, Petros Koidis, Konstantinos M. Paraskevopoulos
Abstract: Melt derived bioactive glass- porcelain system is reported to be bioactive but with a slow rate of bioactivity. The aim of this work is to fabricate and characterize bioactive glass/dental porcelain composites produced by the sol-gel method. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD) were used to characterize the fabricated materials. The FTIR spectra and the XRD patterns confirm the presence of both constituents in the mixtures, while the dominant crystal phases in bioactive glass/dental porcelain specimens are leucite and wollastonite.
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Authors: Eleana Kontonasaki, A. Sivropoulou, Lambrini Papadopoulou, P. Garefis, Konstantinos M. Paraskevopoulos, Petros Koidis
Abstract: The effect of fibronectin (FN) on human periodontal ligament fibroblasts (PDLF) attachment and proliferation on Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials) modified dental ceramics, was investigated in vitro. FN introduced limited alterations in cell attachment on Bioglass®-modified dental ceramics in comparison with the corresponding non-FN-coated specimens but had a profound positive effect on Bioglass®-coated specimens that weakly supported both cell attachment and proliferation. The amount of protein adsorbed on the specimens was not proportional to its biological activity, i.e. cell attachment, spread and proliferation, probably due to surface energy variations and FN conformational changes induced by differences in surface composition and morphology of the different dental ceramics modifications.
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Authors: George Theodorou, Ourania Menti Goudouri, Lambrini Papadopoulou, Nikolaos Kantiranis, Subramaniam Yugeswaran, Akira Kobayashi, Konstantinos M. Paraskevopoulos
Abstract: The clinical use of plasma-sprayed hydroxyapatite (HA) coatings on metal implants has been widely investigated as the HA coating can achieve the firm and direct biological fixation with the surrounding bone tissue. It is shown in previous studies that the mechanical properties of HA coatings are improved by the addition of ZrO2 particles during the deposition of the coating on the substrate. Subsequently, the cohesive and adhesive strengths of plasma-sprayed hydroxyapatite (HA) coatings were strengthened by the ZrO2 particles addition as a reinforcing agent in the HA coating (HA+ZrO2 composite coating). The aim of the present work is to investigate and evaluate the in vitro bioactivity assessment of HA and HA/ZrO2 coatings, on stainless steel substrate, soaked in c-SBF, in order to study and compare their biological responses. The coatings were produced using vapor plasma spraying (VPS). The characterization of the surface of the coatings before and after soaking in SBF solution was performed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction analysis (XRD). All samples were smoothed before insertion in the medium and the in vitro bioactivity of all coating samples was tested in conventional Simulated Body Fluid (c-SBF) solution for various immersion times.
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Authors: Xanthippi Chatzistavrou, Nikolaos Kantiranis, Lambrini Papadopoulou, Eleana Kontonasaki, Aldo Roberto Boccaccini, Petros Koidis, Konstantinos M. Paraskevopoulos
Abstract: In this study new ternary bioactive mixtures were investigated, which are appropriate for applications as coatings on the surface of dental ceramics. The fabrication of mixtures based on the combination of dental ceramic, hydroxyapatite and bioactive glass was demonstrated. The mixtures were characterized by FTIR, XRD and SEM and their bioactive behavior was investigated by immersion in Simulated Body Fluid (SBF). The ternary mixture consisted of a high fusing leucite-feldspathic dental ceramic which exhibited the highest bioactive behavior assigned to the characteristic crystal phases occurring under the specific heat treatment investigated.
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Authors: Eleana Kontonasaki, Lambrini Papadopoulou, T. Zorba, E. Siarampi, K. Papazisis, A. Kortsaris, Konstantinos M. Paraskevopoulos, Petros Koidis
Abstract: The bioactivity of a glass ionomer luting cement (Ketac®-cem, ESPE, Germany), which was modified by Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials) in different bioglass/powder weight ratios, and the biocompatibility of the produced mixtures were evaluated in this study using different cell lines. The incorporation of Bioglass® in the cement structure resulted in the formation of sparsely located biological apatite aggregations. However, although Bioglass® incorporation seemed to enhance cell proliferation, the materials became eventually brittle and highly soluble depending on Bioglass® amount.
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Authors: Eleana Kontonasaki, K. Papazisis, Lambrini Papadopoulou, T. Zorba, A. Kortsaris, P. Garefis, Konstantinos M. Paraskevopoulos, Petros Koidis
Abstract: The bioactivity and biocompatibility of a zinc phosphate luting cement (HARVARD, Richter & Hoffmann, Dental-GmbH, Berlin) which was modified by Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials), was evaluated in vitro with human lung fibroblasts (MRC-5), baby hamster kidney fibroblasts (BHK) and rat pulp cells (RPC) by XTT and BrdU assays. A thin Ca-P layer was grown on the surface of Bioglass®-modified zinc phosphate cement specimens after immersion in SBF for 7 days and remained constant after 16 days immersion time. The incorporation of Bioglass® powder in zinc phosphate specimens resulted in equal or increased cell attachment and activity for almost all cell lines examined without any apparent impact on mechanical or physicochemical properties of the cement, although this needs further documentation. The combination of these two methods in determining the biocompatibility of Bioglass®-modified zinc phosphate cements showed that cells not only attached well on modified specimens but were actively synthesizing DNA after 72h of incubation.
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Authors: Ourania Menti Goudouri, Eleana Kontonasaki, Xanthippi Chatzistavrou, Lambrini Papadopoulou, Petros Koidis, Konstantinos M. Paraskevopoulos
Abstract: Sol-gel derived glasses have been reported to express considerably higher bioactivity than melt-derived ones. The use of the sol-gel method for the fabrication of dental ceramic bioactive glass composites has resulted in composites consisting of an amorphous glassy network into which crystals of Calcium Silicate (CS), Wollastonite (W), leucite (Lt) and Fluorapatite (FAp) are dispersed. Thus, the aim of the present study was the investigation of the bioactivity of sol-gel derived dental ceramic/bioactive glass composites, in the form of powders and in thermally treated disk shaped specimens. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to characterize the reacted products. The sol-gel derived dental glass ceramic composites present high bioactivity compared to the respective melt-derived ones, which is attributed to the higher CaO content and the crystallization of bioactive W and CS crystal phases during the fabrication process. However, the powdered samples presented faster HCAp formation compared to the respective specimens, due to their higher surface energy.
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Authors: Ourania Menti Goudouri, Eleni Theodosoglou, Anna Theocharidou, Eleana Kontonasaki, Lambrini Papadopoulou, Xanthippi Chatzistavrou, Petros Koidis, Konstantinos M. Paraskevopoulos
Abstract: Scaffold-based tooth engineering is currently the most popular approach towards replacing dental tissues or even engineering a bio-tooth. Although, various scaffold materials have been employed in tooth regeneration, the scaffold-based tooth design has, until now, achieved only limited success. Recently, bioactive Mg-based ceramics have attracted interest as Mg plays an important role on skeletal metabolism and affects the quality and structure of hard dental tissues. Mg has been reported to improve the mechanical properties of calcium phosphate ceramics, control biodegradation rate and stabilize the cell-material interface improving cell attachment and growth. The aim of this study was the development of an experimental Mg-based ceramic material, with enhanced bioactivity and adequate mechanical properties, in order to be potentially used in dental tissue regeneration. The Mg-based ceramic was prepared by the sol-gel method, while the stabilization was performed at 1300, 1400 and 1450oC in order a fully crystalline material to be obtained. The characterization of the materials -before and after immersion is Simulated Body Fluid (SBF)- was performed by Fourier Tranform Infrared Spectroscopy (FTIR), X-Ray Diffractometry (XRD) and Scanning Electron Microscopy associated with an EDS analyzer (SEM-EDS), while the flexural strength of uniaxially pressed pellets was measured using a universal testing machine for 3- point bending tests (Instron 3344). FTIR spectra and XRD patterns of all powder samples before immersion in SBF solution confirmed the presence of three crystalline phases; akermanite, merwinite and diopside. The onset of apatite formation on the surface of all powders was observed even after three days of immersion, while the apatite formation on the surface of the sintered pellets was slightly delayed. Flexural strength values were in the range of 30Mpa. In conclusion, Mg-based glass-ceramics attain adequate mechanical integrity and high rate of bioactivity and could be potentially used in the construction of ceramic scaffolds for dental tissue regeneration.
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Authors: Xanthippi Chatzistavrou, E. Hatzistavrou, Nikolaos Kantiranis, Lambrini Papadopoulou, Eleana Kontonasaki, K. Chrissafis, Petros Koidis, Konstantinos M. Paraskevopoulos, Aldo Roberto Boccaccini
Abstract: The aim of this study was the fabrication using a sol-gel technique of a new glass-ceramic with potential use in dental applications. The characterization of the composition and microstructural properties of the produced material confirmed the similarity between the new sol-gel derived glass-ceramic and a commercial leucite based fluorapatite dental glass-ceramic. The produced material has potential application in dental restorations and it is expected to exhibit better control of composition, microstructure and properties due to the intrinsic advantages of the sol-gel preparation method.
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Authors: Anna Theocharidou, K. Tsoptsias, Eleana Kontonasaki, Lambrini Papadopoulou, C. Panayiotou, Konstantinos M. Paraskevopoulos, Petros Koidis
Abstract: Chitin is a polysaccharide abundant in nature. Its’ deacetylation product-chitosan- in combination with gelatin (collagen product) is commonly used as biopolymer scaffold for tissue engineering. The aim of this study was to investigate diffrerences in surface characteristics of chitin (CHN CCS) and chitosan –gelatin (CHS-G CCS) composite ceramic scaffolds (CCS), during their incubation in culture medium (DMEM) with or without human periodontal ligament fibroblasts (HPDLF). CHN CCS and CHS- G CCS, with pore size 70-200μm, were fabricated on the surface of ceramic disks, being coated with a mixture of bioactive glass – ceramic (1:1 wt). Three CCSs of each type were constructed. Each CCS was incubated at 37 °C up to 10 days, either only in DMEM supplemented with 10% FCS or in DMEM with the presence of 105 HPDLF. SEM microphotographs and EDS analysis, before and after incubation, were used to investigate CCSs’ surface alterations. Before incubation, all type of CCSs appeared to be macro porous with high interconnectivity. Exposed to incubation, CHN CCSs’ surface porosity seemed to be rapidly reduced and a rough surface without pores was observed with or without HPDLF. Attached HPDLF were rarely detected. CHS-G CCSs appeared to retain surface porosity in DMEM without cells. In HPDLF culture an almost uniform surface with organic aggregates and attached cells was observed. Until day 10, HPDLF could only be detected at CHS-G CCS’s surface. Conclusion: SEM microphotographs observations indicate that CHN CCSs’ incubation in DMEM led in early and rapid coalescence of surface pores, thus inhibiting HPDLF attachment. HPDLF attachment on CHS-G CCSs confirm the beneficial role of gelatin, while differences in CHS-G CCSs’ surface with and without HPDLF culture indicate that not only sedimentation of medium's ingredients, but cell attachment and function could decrease surface’s porosity, affecting consequently HPDLF proliferation.
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