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Lopez E Cabarcos - One of the best experts on this subject based on the ideXlab platform.
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loading and release of doxycycline hyclate from strontium substituted calcium phosphate Cement
Acta Biomaterialia, 2010Co-Authors: Hamdan M Alkhraisat, Jatsue Cabrejosazama, Julia Lucasaparicio, Tamimi F Marino, Torres J Garciadenche, Blanco L Jerez, Carmen Rueda, Uwe Gbureck, Lopez E CabarcosAbstract:Abstract Novel Sr-substituted calcium phosphate Cement (CPC) loaded with doxycycline hyclate (DOXY-h) was employed to elucidate the effect of strontium substitution on antibiotic delivery. The Cement was prepared using as reactants Sr-substituted β-tricalcium phosphate (Sr-β-TCP) and acidic monocalcium phosphate monohydrate. Two different methods were used to load DOXY-h: (i) the adsorption on CPC by incubating the Set Cement in drug-containing solutions; and (ii) the use of antibiotic solution as the Cement liquid phase. The results revealed that the Sr-substituted Cement efficiently adsorbs the antibiotic, which is attributed to an enhanced accessibility to the drug-binding sites within this CPC. DOXY-h desorption is influenced by the initial adsorbed amount and the Cement matrix type. Furthermore, the fraction of drug released from CPCs Set with DOXY-h solution was higher, and the release rate was faster for the CPC prepared with 26.7% Sr-β-TCP. The analysis of releasing profiles points to Fickian diffusion as the mechanism responsible for antibiotic delivery. We can conclude that Sr substitution in secondary calcium phosphate Cements improves their efficiency for DOXY-h adsorption and release. The antibiotic loading method provides a way to switch from rapid and complete to slower and prolonged drug release.
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loading and release of doxycycline hyclate from strontium substituted calcium phosphate Cement
Acta Biomaterialia, 2010Co-Authors: Hamdan M Alkhraisat, Jatsue Cabrejosazama, Julia Lucasaparicio, Tamimi F Marino, Torres J Garciadenche, Blanco L Jerez, Carmen Rueda, Uwe Gbureck, Lopez E CabarcosAbstract:Novel Sr-substituted calcium phosphate Cement (CPC) loaded with doxycycline hyclate (DOXY-h) was employed to elucidate the effect of strontium substitution on antibiotic delivery. The Cement was prepared using as reactants Sr-substituted beta-tricalcium phosphate (Sr-beta-TCP) and acidic monocalcium phosphate monohydrate. Two different methods were used to load DOXY-h: (i) the adsorption on CPC by incubating the Set Cement in drug-containing solutions; and (ii) the use of antibiotic solution as the Cement liquid phase. The results revealed that the Sr-substituted Cement efficiently adsorbs the antibiotic, which is attributed to an enhanced accessibility to the drug-binding sites within this CPC. DOXY-h desorption is influenced by the initial adsorbed amount and the Cement matrix type. Furthermore, the fraction of drug released from CPCs Set with DOXY-h solution was higher, and the release rate was faster for the CPC prepared with 26.7% Sr-beta-TCP. The analysis of releasing profiles points to Fickian diffusion as the mechanism responsible for antibiotic delivery. We can conclude that Sr substitution in secondary calcium phosphate Cements improves their efficiency for DOXY-h adsorption and release. The antibiotic loading method provides a way to switch from rapid and complete to slower and prolonged drug release.
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vertical bone augmentation with granulated brushite Cement Set in glycolic acid
Journal of Biomedical Materials Research Part A, 2007Co-Authors: Tamimi F Marino, Blanco L Jerez, Jesus Torres, Isabel F Tresguerres, Lopez E CabarcosAbstract:Brushite Cements are a biocompatible materials that are resorbed in vivo. A new Cement composed of a mixture of monocalcium phosphate (MCP) and beta-tricalcium phosphate (beta-TCP) that Sets using glycolic acid (GA) was synthesized and characterized. After Setting, the Cement composition, derived from X-ray diffraction, was 83 wt % brushite and 17 wt % beta-TCP with an average brushite crystal size of about 2.6 +/- 1.4 microm. The Cement has a diametral tensile strength of 2.9 +/- 0.7 MPa. Granules prepared from the Set-Cement were used as grafting material in bone defects on rabbit calvaria for evaluating in vivo its bone regeneration capacity. Considerable Cement resorption, improvement in the bone mineral density, and bone neoformation was observed after 4 weeks of the granules' implantation.
Ihtesham Ur Rehman - One of the best experts on this subject based on the ideXlab platform.
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modifications in glass ionomer Cements nano sized fillers and bioactive nanoceramics
International Journal of Molecular Sciences, 2016Co-Authors: Shariq Najeeb, Zohaib Khurshid, Muhammad Sohail Zafar, Abdul Samad Khan, Sana Zohaib, Juan Manuel Nunez Marti, Salvatore Sauro, J P Matinlinna, Ihtesham Ur RehmanAbstract:Glass ionomer Cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the Set matrix, apatites can make the Set Cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties.
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synthesis and characterization of a novel fast Set proline derivative containing glass ionomer Cement with enhanced mechanical properties
Acta Biomaterialia, 2009Co-Authors: Alireza Moshaverinia, Nima Roohpour, Ihtesham Ur RehmanAbstract:In this study, a methacryloyl derivative of l-proline was synthesized, characterized and incorporated into a conventional glass ionomer Cement (GIC) with a polyacid composition. Subsequently, the effects of incorporation of synthesized N-methacryloyl-proline and terpolymer on the GIC's mechanical and working properties were studied. 1-Methacryloylpyrrolidone-2-carboxylic acid was synthesized and used in a polymerization reaction with acrylic acid and itaconic acid in order to form terpolymer which was used in Fuji II commercial GIC formulations. Chemical structural characterization of the resulting products was performed using (1)H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The viscosity and molecular weight of the terpolymer were also measured. The mechanical strength properties of the modified GICs were evaluated after 24h or 1 week of immersion in distilled water at 37 degrees C. Analysis of variance was used to study the statistical significance of the mechanical strengths and working properties, and to compare them with a control group. Results showed that N-methacryloyl-proline modified GICs exhibited significantly higher compressive strength (CS; 195-210MPa), higher diametral tensile strength (DTS; 19-26MPa) and higher biaxial flexural strength (38-46MPa) in comparison to Fuji II GIC (161-166MPa in CS, 12-14MPa in DTS and 13-18MPa in biaxial flexural strength). The working properties (Setting and working time) of the modified samples showed that the modified Cement was a fast-Set Cement. It was concluded that a novel amino acid-containing GIC has been developed in this study with 27%, 94% and 170% increases in values for compressive, diametral tensile and biaxial flexural strength, respectively, in comparison to commercial Fuji II GIC.
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synthesis and characterization of a novel fast Set proline derivative containing glass ionomer Cement with enhanced mechanical properties
Acta Biomaterialia, 2009Co-Authors: Alireza Moshaverinia, Nima Roohpour, Ihtesham Ur RehmanAbstract:In this study, a methacryloyl derivative of l-proline was synthesized, characterized and incorporated into a conventional glass ionomer Cement (GIC) with a polyacid composition. Subsequently, the effects of incorporation of synthesized N-methacryloyl-proline and terpolymer on the GIC's mechanical and working properties were studied. 1-Methacryloylpyrrolidone-2-carboxylic acid was synthesized and used in a polymerization reaction with acrylic acid and itaconic acid in order to form terpolymer which was used in Fuji II commercial GIC formulations. Chemical structural characterization of the resulting products was performed using 1H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The viscosity and molecular weight of the terpolymer were also measured. The mechanical strength properties of the modified GICs were evaluated after 24 h or 1 week of immersion in distilled water at 37 °C. Analysis of variance was used to study the statistical significance of the mechanical strengths and working properties, and to compare them with a control group. Results showed that N-methacryloyl-proline modified GICs exhibited significantly higher compressive strength (CS; 195-210 MPa), higher diametral tensile strength (DTS; 19-26 MPa) and higher biaxial flexural strength (38-46 MPa) in comparison to Fuji II GIC (161-166 MPa in CS, 12-14 MPa in DTS and 13-18 MPa in biaxial flexural strength). The working properties (Setting and working time) of the modified samples showed that the modified Cement was a fast-Set Cement. It was concluded that a novel amino acid-containing GIC has been developed in this study with 27%, 94% and 170% increases in values for compressive, diametral tensile and biaxial flexural strength, respectively, in comparison to commercial Fuji II GIC. © 2008 Acta Materialia Inc.
Chiara F Ferraris - One of the best experts on this subject based on the ideXlab platform.
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rheology and Setting of high volume fly ash mixtures
Cement & Concrete Composites, 2010Co-Authors: Dale P Bentz, Chiara F FerrarisAbstract:While high volume fly ash (HVFA) concretes can be designed and produced to meet 28-d strength requirements and often even exceed the durability performance of conventional concretes, a persistent problem is the potentially long delay in Setting time that produces concurrently long delays in finishing the concrete in the field. Previous isothermal calorimetry studies on two different powder additions, namely calcium hydroxide and a rapid Set Cement, have shown that these powders can mitigate excessive retardation of the hydration reactions. In this paper, rheological measurements and conventional Vicat Setting time studies are conducted to verify that these powder additions do indeed reduce Setting times in paste systems based on both ASTM Class C and ASTM Class F fly ashes. The reductions depend on the class of fly ash and suggest that trial mixtures would be a necessity to apply these technologies to each specific fly ash/Cement/admixture combination being employed in the field. Potentially, for such screening studies, the rheological measurement of yield stress may provide a faster indication of Setting (and finishability) than conventional Vicat needle penetration measurements on pastes.
Tamimi F Marino - One of the best experts on this subject based on the ideXlab platform.
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loading and release of doxycycline hyclate from strontium substituted calcium phosphate Cement
Acta Biomaterialia, 2010Co-Authors: Hamdan M Alkhraisat, Jatsue Cabrejosazama, Julia Lucasaparicio, Tamimi F Marino, Torres J Garciadenche, Blanco L Jerez, Carmen Rueda, Uwe Gbureck, Lopez E CabarcosAbstract:Abstract Novel Sr-substituted calcium phosphate Cement (CPC) loaded with doxycycline hyclate (DOXY-h) was employed to elucidate the effect of strontium substitution on antibiotic delivery. The Cement was prepared using as reactants Sr-substituted β-tricalcium phosphate (Sr-β-TCP) and acidic monocalcium phosphate monohydrate. Two different methods were used to load DOXY-h: (i) the adsorption on CPC by incubating the Set Cement in drug-containing solutions; and (ii) the use of antibiotic solution as the Cement liquid phase. The results revealed that the Sr-substituted Cement efficiently adsorbs the antibiotic, which is attributed to an enhanced accessibility to the drug-binding sites within this CPC. DOXY-h desorption is influenced by the initial adsorbed amount and the Cement matrix type. Furthermore, the fraction of drug released from CPCs Set with DOXY-h solution was higher, and the release rate was faster for the CPC prepared with 26.7% Sr-β-TCP. The analysis of releasing profiles points to Fickian diffusion as the mechanism responsible for antibiotic delivery. We can conclude that Sr substitution in secondary calcium phosphate Cements improves their efficiency for DOXY-h adsorption and release. The antibiotic loading method provides a way to switch from rapid and complete to slower and prolonged drug release.
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loading and release of doxycycline hyclate from strontium substituted calcium phosphate Cement
Acta Biomaterialia, 2010Co-Authors: Hamdan M Alkhraisat, Jatsue Cabrejosazama, Julia Lucasaparicio, Tamimi F Marino, Torres J Garciadenche, Blanco L Jerez, Carmen Rueda, Uwe Gbureck, Lopez E CabarcosAbstract:Novel Sr-substituted calcium phosphate Cement (CPC) loaded with doxycycline hyclate (DOXY-h) was employed to elucidate the effect of strontium substitution on antibiotic delivery. The Cement was prepared using as reactants Sr-substituted beta-tricalcium phosphate (Sr-beta-TCP) and acidic monocalcium phosphate monohydrate. Two different methods were used to load DOXY-h: (i) the adsorption on CPC by incubating the Set Cement in drug-containing solutions; and (ii) the use of antibiotic solution as the Cement liquid phase. The results revealed that the Sr-substituted Cement efficiently adsorbs the antibiotic, which is attributed to an enhanced accessibility to the drug-binding sites within this CPC. DOXY-h desorption is influenced by the initial adsorbed amount and the Cement matrix type. Furthermore, the fraction of drug released from CPCs Set with DOXY-h solution was higher, and the release rate was faster for the CPC prepared with 26.7% Sr-beta-TCP. The analysis of releasing profiles points to Fickian diffusion as the mechanism responsible for antibiotic delivery. We can conclude that Sr substitution in secondary calcium phosphate Cements improves their efficiency for DOXY-h adsorption and release. The antibiotic loading method provides a way to switch from rapid and complete to slower and prolonged drug release.
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vertical bone augmentation with granulated brushite Cement Set in glycolic acid
Journal of Biomedical Materials Research Part A, 2007Co-Authors: Tamimi F Marino, Blanco L Jerez, Jesus Torres, Isabel F Tresguerres, Lopez E CabarcosAbstract:Brushite Cements are a biocompatible materials that are resorbed in vivo. A new Cement composed of a mixture of monocalcium phosphate (MCP) and beta-tricalcium phosphate (beta-TCP) that Sets using glycolic acid (GA) was synthesized and characterized. After Setting, the Cement composition, derived from X-ray diffraction, was 83 wt % brushite and 17 wt % beta-TCP with an average brushite crystal size of about 2.6 +/- 1.4 microm. The Cement has a diametral tensile strength of 2.9 +/- 0.7 MPa. Granules prepared from the Set-Cement were used as grafting material in bone defects on rabbit calvaria for evaluating in vivo its bone regeneration capacity. Considerable Cement resorption, improvement in the bone mineral density, and bone neoformation was observed after 4 weeks of the granules' implantation.
J A Delgado - One of the best experts on this subject based on the ideXlab platform.
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α tricalcium phosphate Cements modified with β dicalcium silicate and tricalcium aluminate physicochemical characterization in vitro bioactivity and cytotoxicity
Journal of Biomedical Materials Research Part B, 2015Co-Authors: Daniel Correa, Amisel Almirall, Raul Garcia Carrodeguas, Luis Alberto Dos Santos, Antonio H De Aza, Juan Parra, L Morejon, J A DelgadoAbstract:Biocompatibility, injectability and in situ self-Setting are characteristics of calcium phosphate Cements which make them promising materials for a wide range of clinical applications in traumatology and maxillo-facial surgery. One of the main disadvantages is their relatively low strength which restricts their use to nonload-bearing applications. α-Tricalcium phosphate (α-C3P) Cement Sets into calcium-deficient hydroxyapatite (CDHA), which is biocompatible and plays an essential role in the formation, growth and maintenance of tissue-biomaterial interface. β-Dicalcium silicate (β-C2S) and tricalcium aluminate (C3A) are Portland Cement components, these compounds react with water to form hydrated phases that enhance mechanical strength of the end products. In this study, Setting time, compressive strength (CS) and in vitro bioactivity and biocompatibility were evaluated to determine the influence of addition of β-C2S and C3A to α-C3P-based Cement. X-ray diffraction and scanning electron microscopy were used to investigate phase composition and morphological changes in Cement samples. Addition of C3A resulted in Cements having suitable Setting times, but low CS, only partial conversion into CDHA and cytotoxicity. However, addition of β-C2S delayed the Setting times but promoted total conversion into CDHA by soaking in simulated body fluid and strengthened the Set Cement over the limit strength of cancellous bone. The best properties were obtained for Cement added with 10 wt % of β-C2S, which showed in vitro bioactivity and cytocompatibility, making it a suitable candidate as bone substitute.
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α tricalcium phosphate Cements modified with β dicalcium silicate and tricalcium aluminate physicochemical characterization in vitro bioactivity and cytotoxicity
Journal of Biomedical Materials Research Part B, 2015Co-Authors: Daniel Correa, Amisel Almirall, Raul Garcia Carrodeguas, Luis Alberto Dos Santos, Juan Parra, L Morejon, J A DelgadoAbstract:Biocompatibility, injectability and in situ self-Setting are characteristics of calcium phosphate Cements which make them promising materials for a wide range of clinical applications in traumatology and maxillo-facial surgery. One of the main disadvantages is their relatively low strength which restricts their use to nonload-bearing applications. α-Tricalcium phosphate (α-C3P) Cement Sets into calcium-deficient hydroxyapatite (CDHA), which is biocompatible and plays an essential role in the formation, growth and maintenance of tissue-biomaterial interface. β-Dicalcium silicate (β-C2S) and tricalcium aluminate (C3A) are Portland Cement components, these compounds react with water to form hydrated phases that enhance mechanical strength of the end products. In this study, Setting time, compressive strength (CS) and in vitro bioactivity and biocompatibility were evaluated to determine the influence of addition of β-C2S and C3A to α-C3P-based Cement. X-ray diffraction and scanning electron microscopy were used to investigate phase composition and morphological changes in Cement samples. Addition of C3A resulted in Cements having suitable Setting times, but low CS, only partial conversion into CDHA and cytotoxicity. However, addition of β-C2S delayed the Setting times but promoted total conversion into CDHA by soaking in simulated body fluid and strengthened the Set Cement over the limit strength of cancellous bone. The best properties were obtained for Cement added with 10 wt % of β-C2S, which showed in vitro bioactivity and cytocompatibility, making it a suitable candidate as bone substitute. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 72–83, 2015.