The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Marco Ferrari - One of the best experts on this subject based on the ideXlab platform.
-
improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane adhesive coupling
Journal of Endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
-
Improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane/adhesive coupling.
Journal of endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
Claudia Giovedi - One of the best experts on this subject based on the ideXlab platform.
-
Thermal behavior of polyacrylonitrile polymers synthesized under different conditions and coMonomer compositions
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Irina F. Catta Preta, Solange K. Sakata, J. P. Zimmermann, Fernando Galembeck, G. Garcia, Claudia GiovediAbstract:Polyacrylonitrile (PAN) polymers are used as precursors for carbon fiber production. This process requires an oxidative stabilization step, which can be studied by differential scanning calorimetry (DSC). In this sense, thermal behavior of PAN based terpolymers by different polymerization processes, compositions and itaconic acid concentrations in the reaction media were investigated. The obtained results showed that the addition of itaconic acid and methyl acrylate as coMonomers resulted a lower heat flow during the process comparing to the PAN homopolymer. It suggested that these coMonomers aid the oxidative stabilization stage for all studied process. The redox system polymerization at 40°C resulted in a lower heat flow. Itaconic acid decreases slightly initial and peak temperatures of the terpolymer and heat flow until concentration of 3y. The cyclization temperature decreases when MAis incorporated into the terpolymer compared to the MMA terpolymer and increases when MAA is the Acidic Monomer. Among terpolymers the AN/MA/AA polymer showed the best thermal behavior for carbon fiber producing.
-
Thermal behavior of polyacrylonitrile polymers synthesized under different conditions and coMonomer compositions
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Irina F. Catta Preta, Solange K. Sakata, J. P. Zimmermann, Fernando Galembeck, G. Garcia, Claudia GiovediAbstract:Polyacrylonitrile (PAN) polymers are used as precursors for carbon fiber production. This process requires an oxidative stabilization step, which can be studied by differential scanning calorimetry (DSC). In this sense, thermal behavior of PAN based terpolymers by different polymerization processes, compositions and itaconic acid concentrations in the reaction media were investigated. The obtained results showed that the addition of itaconic acid and methyl acrylate as coMonomers resulted a lower heat flow during the process comparing to the PAN homopolymer. It suggested that these coMonomers aid the oxidative stabilization stage for all studied process. The redox system polymerization at 40°C resulted in a lower heat flow. Itaconic acid decreases slightly initial and peak temperatures of the terpolymer and heat flow until concentration of 3y. The cyclization temperature decreases when MAis incorporated into the terpolymer compared to the MMA terpolymer and increases when MAA is the Acidic Monomer. Among terpolymers the AN/MA/AA polymer showed the best thermal behavior for carbon fiber producing.
Franklin R. Tay - One of the best experts on this subject based on the ideXlab platform.
-
pka value and buffering capacity of Acidic Monomers commonly used in self etching primers
Journal of Adhesive Dentistry, 2006Co-Authors: Ulrich Dr Salz, Franklin R. Tay, Angela Dr Mucke, Jorg Zimmermann, David H PashleyAbstract:Purpose The aim of this investigation was to characterize Acidic Monomers used in self-etching primers/adhesives by determination of their pKa values and by calculation of their calcium dissolving capacity in comparison with phosphoric and hydrochloric acid. Materials and methods The following Acidic Monomers were included in this study: 4-methacryloyloxyethyl trimellitate anhydride (4-META), 10-methacryloyloxydecyl dihydrogen phosphate (MDP), dimethacryloyloxyethyl hydrogen phosphate (di-HEMA-phosphate), ethyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (EAEPA), 2-[4-(dihydroxyphosphoryl)-2-ox-abutyl]acrylic acid (HAEPA), and 2,4,6 trimethylphenyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (MAEPA). The pKa values were obtained by titration with 0.1 mol/l NaOH in aqueous solution. The inflection points of the resulting potentiometric titration curve were determined as pKa values. In the case of the sparingly water-soluble Acidic Monomers MAEPA and 4-META, the co-solvent method using different water/ethanol ratios for MAEPA or water/acetone ratios for 4-META was used. The dissolving capacity of each Acidic Monomer is defined as the amount of hydroxyapatite (HA) dissolved by 1 g of acid. For each Monomer, the HA dissolving capacity was calculated bythe corresponding pKa value and the molecular weight. To confirm the calculated dissolving capacities, increasing amounts of HA powder (100 mg portions) were slowly added to 15 mmol/l aqueous solutions of the Monomers to determine how much HA could be dissolved in the Acidic solutions. Results For all the investigated Acidic Monomers, pKal values between 1.7 to 2.5 were observed. The pKa2 values for the phosphate/phosphonate derivatives are between 7.0 and 7.3, and are comparable to phosphoric acid. For dicarboxylic acid derivatives, the pKa2 values are in the range of 4.2 to 4.5. Due to their comparable molecular weights and pKal values, the three tested acids di-HEMA phosphate, MDP and 4-META all possess comparable dissolving capacities for HA (ie, 0.26 to 0.28 g/g Monomer). The same amount by weight of Acidic Monomer EAEPA dissolved more HA (ie, 0.35 g/g Monomer). Due to their different molecular weights, phosphoric acid and hydrochloric acid dissolved three and ten times as much HA, respectively, as the first three Acidic Monomers. As a result, the ability of these acids to dissolve HA increases as their molecular weight decreases. Conclusion There are no significant differences among the investigated Acidic Monomers in terms of their pKa values and HA dissolving capacities. Monomer selection criteria for new self-etching adhesives must include properties such as calcium salt stability, wetting of the substrate, and copolymerization behavior.
-
improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane adhesive coupling
Journal of Endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
-
Improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane/adhesive coupling.
Journal of endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
Francesca Monticelli - One of the best experts on this subject based on the ideXlab platform.
-
improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane adhesive coupling
Journal of Endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
-
Improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane/adhesive coupling.
Journal of endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
Raquel Osorio - One of the best experts on this subject based on the ideXlab platform.
-
improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane adhesive coupling
Journal of Endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
-
Improving the quality of the quartz fiber postcore bond using sodium ethoxide etching and combined silane/adhesive coupling.
Journal of endodontics, 2006Co-Authors: Francesca Monticelli, Raquel Osorio, Manuel Toledano, Cecilia Goracci, Franklin R. Tay, Marco FerrariAbstract:The influence of different silane/dentin adhesives on the microtensile bond strengths of a hybrid composite to sodium ethoxide-etched quartz fiber posts was investigated. A prehydrolyzed silane was applied without an adhesive and compared to two-component systems in which hydrolysis of the silane occurred after mixing with the Acidic Monomer present in the dentin adhesives. Nanoleakage along post/core interfaces was examined after silver nitrate tracer penetration using scanning electron microscopy. Higher interfacial strengths and more uniform adaptation between the etched fiber post surface and the composite core were recorded after post treatment with silane/adhesive couplings. The combination of silane with two-step self-etch adhesives improves the chemical retention of composites around etched fiber posts with minimal nanoleakage. Although the one-step self-etching adhesive/silane combination enhances post adhesion, the extensive nanoleakage provides channels for rapid water sorption that may expedite hydrolytic degradation of the post/core interface.
