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Alfredo T.n. Pires - One of the best experts on this subject based on the ideXlab platform.
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Investigations on cure kinetics and thermal degradation of stereolithography Renshape™ 5260 photosensitive Resin
Polymer Testing, 2008Co-Authors: Gean V. Salmoria, P. Klauss, Alfredo T.n. Pires, J. Roeder, Valdir SoldiAbstract:Abstract The stereolithography Resin Renshape™ 5260 was characterized by infrared and nuclear magnetic resonance spectroscopy, indicating the presence of epoxy and acrylic reactive groups as well as aromatic and aliphatic ether groups. Infrared spectroscopy was also used to evaluate the curing process and identify the components of the thermal degradation of liquid and Cured Resins. Kinetics studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process. The Cured Resin had only one degradation stage with activation energy of 90–250 kJ mol −1 in the weight loss fraction of 0.10–0.92, whereas a second degradation stage was observed for the liquid Resin above the 0.6 weight loss fraction. This second degradation stage gives E a values in the range of 70–140 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage observed for the former suggest a different decomposition mechanism and stability of the Cured Resin at higher temperatures compared to the liquid Resin.
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Stereolithography Somos 7110 photosensitive Resin: study of curing kinetic and thermal degradation
Journal of Materials Processing Technology, 2005Co-Authors: Gean V. Salmoria, Valdir Soldi, V.j. Gonzalez, Carlos Henrique Ahrens, Alfredo T.n. PiresAbstract:Different types of photopolymers, also called photosensitive Resins, have been used in the stereolithography process to obtain specimens with specific size and application. The Somos 7110 Resin evaluated in this study was characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, indicating the presence of epoxy and acrylic functional groups, as well as, aromatics and aliphatic ether groups. Infrared spectroscopy was also used as the technique to evaluate the curing process and identify the components of thermal degradation of liquid and Cured Resin. Thermogravimetric analysis was other complementary procedure used to quantify the components formed in the degradation process and determines the related physicochemical parameters. The kinetic studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process, which was very close to unity. The Cured Resin had only one degradation stage with activation energy of 100–125 kJ mol −1 in the weight loss fraction of 0.20–0.85, in contrast to the second degradation stage observed for liquid Resin above the 0.5-weight loss fraction. This second degradation stage gives Ea-values in the range 210–260 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage suggest different decomposition mechanisms and a stability of the Cured Resin at higher temperatures compared to the liquid Resin.
Valdir Soldi - One of the best experts on this subject based on the ideXlab platform.
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Investigations on cure kinetics and thermal degradation of stereolithography Renshape™ 5260 photosensitive Resin
Polymer Testing, 2008Co-Authors: Gean V. Salmoria, P. Klauss, Alfredo T.n. Pires, J. Roeder, Valdir SoldiAbstract:Abstract The stereolithography Resin Renshape™ 5260 was characterized by infrared and nuclear magnetic resonance spectroscopy, indicating the presence of epoxy and acrylic reactive groups as well as aromatic and aliphatic ether groups. Infrared spectroscopy was also used to evaluate the curing process and identify the components of the thermal degradation of liquid and Cured Resins. Kinetics studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process. The Cured Resin had only one degradation stage with activation energy of 90–250 kJ mol −1 in the weight loss fraction of 0.10–0.92, whereas a second degradation stage was observed for the liquid Resin above the 0.6 weight loss fraction. This second degradation stage gives E a values in the range of 70–140 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage observed for the former suggest a different decomposition mechanism and stability of the Cured Resin at higher temperatures compared to the liquid Resin.
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Stereolithography Somos 7110 photosensitive Resin: study of curing kinetic and thermal degradation
Journal of Materials Processing Technology, 2005Co-Authors: Gean V. Salmoria, Valdir Soldi, V.j. Gonzalez, Carlos Henrique Ahrens, Alfredo T.n. PiresAbstract:Different types of photopolymers, also called photosensitive Resins, have been used in the stereolithography process to obtain specimens with specific size and application. The Somos 7110 Resin evaluated in this study was characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, indicating the presence of epoxy and acrylic functional groups, as well as, aromatics and aliphatic ether groups. Infrared spectroscopy was also used as the technique to evaluate the curing process and identify the components of thermal degradation of liquid and Cured Resin. Thermogravimetric analysis was other complementary procedure used to quantify the components formed in the degradation process and determines the related physicochemical parameters. The kinetic studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process, which was very close to unity. The Cured Resin had only one degradation stage with activation energy of 100–125 kJ mol −1 in the weight loss fraction of 0.20–0.85, in contrast to the second degradation stage observed for liquid Resin above the 0.5-weight loss fraction. This second degradation stage gives Ea-values in the range 210–260 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage suggest different decomposition mechanisms and a stability of the Cured Resin at higher temperatures compared to the liquid Resin.
Gean V. Salmoria - One of the best experts on this subject based on the ideXlab platform.
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Investigations on cure kinetics and thermal degradation of stereolithography Renshape™ 5260 photosensitive Resin
Polymer Testing, 2008Co-Authors: Gean V. Salmoria, P. Klauss, Alfredo T.n. Pires, J. Roeder, Valdir SoldiAbstract:Abstract The stereolithography Resin Renshape™ 5260 was characterized by infrared and nuclear magnetic resonance spectroscopy, indicating the presence of epoxy and acrylic reactive groups as well as aromatic and aliphatic ether groups. Infrared spectroscopy was also used to evaluate the curing process and identify the components of the thermal degradation of liquid and Cured Resins. Kinetics studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process. The Cured Resin had only one degradation stage with activation energy of 90–250 kJ mol −1 in the weight loss fraction of 0.10–0.92, whereas a second degradation stage was observed for the liquid Resin above the 0.6 weight loss fraction. This second degradation stage gives E a values in the range of 70–140 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage observed for the former suggest a different decomposition mechanism and stability of the Cured Resin at higher temperatures compared to the liquid Resin.
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Stereolithography Somos 7110 photosensitive Resin: study of curing kinetic and thermal degradation
Journal of Materials Processing Technology, 2005Co-Authors: Gean V. Salmoria, Valdir Soldi, V.j. Gonzalez, Carlos Henrique Ahrens, Alfredo T.n. PiresAbstract:Different types of photopolymers, also called photosensitive Resins, have been used in the stereolithography process to obtain specimens with specific size and application. The Somos 7110 Resin evaluated in this study was characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, indicating the presence of epoxy and acrylic functional groups, as well as, aromatics and aliphatic ether groups. Infrared spectroscopy was also used as the technique to evaluate the curing process and identify the components of thermal degradation of liquid and Cured Resin. Thermogravimetric analysis was other complementary procedure used to quantify the components formed in the degradation process and determines the related physicochemical parameters. The kinetic studies indicated that this solvent-free polymerization was diffusion-controlled during the chemical crosslinking, due to the reaction order of the curing process, which was very close to unity. The Cured Resin had only one degradation stage with activation energy of 100–125 kJ mol −1 in the weight loss fraction of 0.20–0.85, in contrast to the second degradation stage observed for liquid Resin above the 0.5-weight loss fraction. This second degradation stage gives Ea-values in the range 210–260 kJ mol −1 . The higher weight loss temperature of the Cured Resin compared with the liquid Resin and the single decomposition stage suggest different decomposition mechanisms and a stability of the Cured Resin at higher temperatures compared to the liquid Resin.
Mitsuru Atsuta - One of the best experts on this subject based on the ideXlab platform.
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Influence of ceramic thickness on mechanical properties and polymer structure of dual-Cured Resin luting agents.
Dental materials : official publication of the Academy of Dental Materials, 2007Co-Authors: Xiang-feng Meng, Keiichi Yoshida, Mitsuru AtsutaAbstract:Abstract Objective To investigate the influence of ceramic thickness on the mechanical properties and polymer structure (degree conversion and cross-linking density) of three dual-Cured Resin luting agents. Methods Three dual-Cured Resin luting agents [Linkmax HV (GC), Nexus 2 (Kerr), and Variolink IIHV (Ivoclar-Vivadent)] were polymerized with or without 800 mW/cm2 irradiation through 0–3-mm-thick GN-I (GC) machinable ceramic. Bar-shape specimens were subjected to three-point bending to determine flexural strength (FS) and elastic modulus (EM) after dry storage at 37 °C for 24 h. Knoop hardness was measured on the irradiated surface of disk-shaped specimens before (KHN1) and after (KHN2) storage of 100% ethanol solution at 37 °C for 24 h. KHN1 and KHN2 were estimated as indirect indicators of degree of conversion (DC) and cross-linking density, respectively. Data were analyzed by one-way ANOVA and Student–Newman–Keuls test for each luting agent, and four mechanical properties were subjected to regression analysis. Results For three Resin luting agents with dual-Cured mode, FS, EM, KHN1, and KHN2 decreased with the increase of ceramic thickness. FS except for Nexus 2 and EM for three Resin luting agents had a positive linear relationship with both KHN1 and KHN2. Significance The variables tested behaved differently. When the ceramic thickness increased, the chemical Cured components of dual-Cured Resin luting agents did not produce significant compensation for all variables. Mechanical properties and polymer structure of dual-Cured Resin luting agents was dependent on the intensity of light irradiation.
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Bonding of dual-Cured Resin cement to zirconia ceramic using phosphate acid ester monomer and zirconate coupler
Journal of Biomedical Materials Research - Part B Applied Biomaterials, 2006Co-Authors: Keiichi Yoshida, Yukiko Tsuo, Mitsuru AtsutaAbstract:This study evaluated the shear bond strength between dual-Cured Resin luting cement and pure zirconium (99.9%) and industrially manufactured yttrium-oxide-partially-stabilized zirconia ceramic, and the effect of MDP (10-methacryloyloxydecyl dihydrogen phosphate) primer (MP) and zirconate coupler (ZC) on bond strength. Two different-shaped pure zirconium and zirconia ceramic specimens were untreated or treated with various primers, including different concentrations of MP containing phosphoric acid ester monomer (MDP) in ethanol, ZC containing a zirconate coupling agent in ethanol, or a mixture of MP and ZC. The specimens were then cemented together with dual-Cured Resin luting cement (Clapearl DC). Half of the specimens were stored in water at 37 degrees C for 24 h and the other half were thermocycled 10,000 times before shear bond strength testing. The bond strengths of Resin luting cement to both the zirconium and zirconia ceramic were enhanced by the application of most MPs, ZCs, and the mixtures of MP and ZC. For the group (MP2.0+ZC1.0) containing 2.0 wt % MP and 1.0 wt % ZC, no significant difference was observed between in shear bond strength before and after thermal cycling for both zirconium and zirconia ceramic (p > 0.05). For the other primers, statistically significant differences in shear bond strength before and after thermal cycling were observed (p < 0.05). The application of the mixture of MP and ZC (MP2.0+ZC1.0) was effective for bonding between zirconia ceramic and dual-Cured Resin luting cement. This primer may be clinically useful as an adhesive primer for zirconia ceramic restoration.
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Hardness development of dual-Cured Resin cements through different thicknesses of ceramics.
Dental materials journal, 2006Co-Authors: Xiang-feng Meng, Keiichi Yoshida, Mitsuru AtsutaAbstract:This study investigated the Knoop hardness of a thin layer in three dual-Cured Resin cements (Linkmax HV, Nexus 2, and Variolink II HV) irradiated through or not through different thicknesses (1 through 5 mm) of a machinable ceramic. Hardness was recorded at a series of time intervals up to five days, starting from the end of a light irradiation period. Increase in hardness was more rapid over the first 0.5 hour; thereafter it continued at a low rate until maximum hardness was attained. Ceramic thickness had a significant influence on hardness in all dual-Cured Resin cements, especially when ceramic thickness was more than 4 mm. In addition, it was noted that the polymerization of Nexus 2 seemed to be more dependent on light exposure compared with the other two materials. Variolink II HV and Linkmax HV, on the other hand, seemed to indicate the potential of being compensated by chemical curing to some degree.
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zirconate coupling agent for bonding Resin luting cement to pure zirconium
American Journal of Dentistry, 2004Co-Authors: Keiichi Yoshida, Maki Yamashita, Mitsuru AtsutaAbstract:PURPOSE To evaluate the shear bond strengths of two dual-Cured Resin luting cements to pure zirconium and the effect of zirconate coupling agent on the bond strength. METHODS The two different-shaped pure zirconium specimens (99.9%) were untreated or treated with one of the four primers including zirconate coupler and then cemented together with one of the two dual-Cured Resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half thermocycled 20,000 times before shear bond strength testing. RESULTS Regardless of the Resin luting cement and thermocycling, specimens treated with the mixture of zirconate coupler and Resin bonding agent showed the highest shear bond strength among the five treatments. Surface treatment with the mixture of zirconate coupler and Resin bonding agent showed significantly greater shear bond strength compared with other treatments at 20,000 thermocycles. The application by the mixture of zirconate coupler and Resin bonding agent on the pure zirconium metal surface appears to be effective for bonding between zirconium and dual-Cured Resin luting cements.
Junji Tagami - One of the best experts on this subject based on the ideXlab platform.
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Effects of light intensity through Resin inlays on the bond strength of dual-Cured Resin cement.
The journal of adhesive dentistry, 2004Co-Authors: Hirofumi Tashiro, Toru Nikaido, Norimichi Inai, Junji TagamiAbstract:PURPOSE To evaluate the influence of the light intensity, irradiation time, and thickness of the indirect restoration composite on the bond strength of dual-Cured Resin cement immediately after cementation, applying the Resin coating technique. MATERIALS AND METHODS Three hundred forty composite blocks as an adhesive surface and four thicknesses of indirect restoration composite disks were prepared. The surface of the composite blocks was coated with low-viscosity Resin composite and immersed in water for 24 h. After immersion, dual-Cured Resin cement was applied to the Resin-coated surface and the indirect restoration composite disks were placed on it. Light irradiation was performed through four thicknesses of indirect restoration composite disks with conventional halogen (40 s) and high intensity (10, 20, 40 s) light units. The specimens were stored in water at 37 degrees C for 10 min or 24 h, and the tensile bond test was performed. RESULTS For the 1-mm composite thickness, there were no significant differences in the bond strengths between 10 min and 24 h after cementation with the four light curing methods. For the composite thicknesses of 3 or 4 mm, the bond strength 24 h after cementation was significantly higher than that at 10 min after cementation with conventional halogen (40 s) and high-intensity light units at 10 s and 20 s, but there was no significant difference with the high-intensity light unit applied for 40 s. CONCLUSION The bond strength of dual-Cured Resin cement immediately after cementation could be greatly influenced by the irradiation time and the light intensity penetrating the indirect restoration composite.
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micro shear bond strength of dual Cured Resin cement to glass ceramics
Dental Materials, 2002Co-Authors: Yasushi Shimada, Saori Yamaguchi, Junji TagamiAbstract:Abstract Objectives: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-Cured Resin cement to bond to glass ceramics designed for in indirect adhesive restoration. Methods: A cast glass ceramic (Olympas Castable Ceramics) with a crystalline phase consisting of mica and β-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-Cured Resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the Resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. Results: Usage of a silane coupling agent effectively raised the bond-strength values of Resin cement (Fisher's PLSD, P P >0.01). HF-etching for 30 s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P Significance: The micro-shear bond strength between Olympas Castable Ceramics and Resin cement can be increased by the silane coupling agent used along with an acidic primer.
