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D P Serrano - One of the best experts on this subject based on the ideXlab platform.
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improvement of the hierarchical ts 1 properties by Silanization of protozeolitic units in presence of alcohols
Microporous and Mesoporous Materials, 2013Co-Authors: D P Serrano, R Sanz, Patricia Pizarro, A Peral, I MorenoAbstract:Abstract The synthesis of hierarchical TS-1 zeolites has been accomplished following a strategy based on the Silanization of protozeolitic units. This kind of zeolites is characterized by having a secondary porosity in the supermicro/mesopore range and, therefore, enhanced textural properties. The generation of this secondary porosity is caused by the presence of the Silanization agent, which acts as crystal growth inhibitor. However, when a high proportion of organosilane is introduced into the synthesis medium, a highly viscous gel is formed, which reduces the anchoring of the organosilane molecules onto the protozeolitic units. In order to improve the Silanization process in these conditions, a variety of alcohols (methanol, ethanol and 2-propanol) has been tested as solvents during the Silanization step. The alcohol addition increases the incorporation of the Silanization agent onto the zeolite, which is attributed to a reduction in the synthesis media viscosity. Likewise, the alcohols may also undergo grafting onto the external surface of the protozeolitic units through alkoxylation reactions, improving the crystal growth inhibitor effect of the Silanization agent. As a consequence, these materials exhibit enhanced textural properties, with a higher secondary porosity contribution, especially when ethanol is used as solvent. Hierarchical TS-1 zeolites prepared adding alcohols in the Silanization step show improved catalytic activity in 1-octene epoxidation using tert-butylhydroperoxide as oxidant, due to a higher proportion of more accessible titanium sites. Moreover, it is noteworthy that a reasonable correlation exists between the catalytic activity and the surface attributed to the secondary porosity.
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synthesis of hierarchical zsm 5 by Silanization and alkoxylation of protozeolitic units
Catalysis Today, 2011Co-Authors: D P Serrano, A Peral, Jose Maria Aguado, J M Escola, Gabriel Morales, E AbellaAbstract:Abstract Hierarchical ZSM-5 zeolite has been synthesized by means of a method involving a precrystallization stage to form the protozeolitic units, the addition and subsequent grafting of both Silanization and alkoxylation agents, and a final hydrothermal crystallization. The influence of the alkoxylation with different alcohols (methanol, ethanol, 2-propanol and n-butanol) on the properties of the final hierarchical ZSM-5 samples has been investigated. In every case, the alcohol addition increased the incorporation of the seed Silanization agent as it decreases the gel viscosity. In addition, the presence of alcohols deeply affects the physicochemical properties of the final materials. The samples prepared with 2-propanol and methanol were highly crystalline and presented improved textural properties with regard to the reference h-ZSM-5 and n-ZSM-5. In contrast, the samples obtained with ethanol and n-butanol were partially and totally X-ray amorphous, respectively. 1H and 13C-CP solid state MAS NMR spectra proved the alkoxylation of the external surface of the protozeolitic units. Catalytic cracking of LDPE pointed out the higher TOF values obtained over the hierarchical samples prepared with methanol and 2-propanol due to a right combination of accessibility and crystallinity in these materials. The differences observed among the samples prepared with alcohols were ascribed to the strong interaction produced between the Silanization agent and the linear alcohols on the surface of the protozeolitic nanounits, which form a very stable protective layer, hindering their aggregation and subsequent crystallization.
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molecular and meso and macroscopic properties of hierarchical nanocrystalline zsm 5 zeolite prepared by seed Silanization
Chemistry of Materials, 2009Co-Authors: D P Serrano, A Peral, Gabriel Morales, J Aguado, J M Rodriguez, Matthias Thommes, Jan D Epping, Bradley F ChmelkaAbstract:Surface-passivating Silanization of protozeolitic units has been shown to be an effective strategy for the preparation of ZSM-5 nanocrystals, showing a controlled aggregation degree and a hierarchical porosity. ZSM-5 zeolite materials are thus obtained with adjustable and relatively uniform mesoporosities that have a strong influence on resulting macroscopic reaction properties, especially for macromolecular reagents. The mean sizes of the nanounits and, therefore, the textural and accessibility of these materials can be varied by changing the precrystallization conditions and the concentration of the seed-Silanization agent. In addition to conventional characterization techniques, solid-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy measurements and the application of the NLDFT model to the argon adsorption isotherms have allowed both the local and the mesoscopic compositions, as well as the structures of the hierarchically porous ZSM-5 materials, to be established. The resultin...
Marco Antonio Bottino - One of the best experts on this subject based on the ideXlab platform.
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bonding of y tzp to dentin effects of y tzp surface conditioning resin cement type and aging
Operative Dentistry, 2014Co-Authors: Marco Antonio Bottino, Cesar Dalmolin Bergoli, E G Lima, Susana Maria Salazar Marocho, Rodrigo Othavio De Assuncao E SouzaAbstract:Clinical Relevance The application of the low-fusing glaze porcelain followed by hydrofluoric acid etching and Silanization and tribochemical silicatization generates strong bonds between resin cement and zirconia. Panavia generates stronger bonds than does Clearfil.
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adhesive quality of self adhesive and conventional adhesive resin cement to y tzp ceramic before and after aging conditions
Operative Dentistry, 2010Co-Authors: Sheila Pestana Passos, Marco Antonio Bottino, Mutlu Ozcan, Liliana Gressler May, Diana Capelli Barca, Luiz Felipe ValandroAbstract:Clinical Relevance Chairside tribochemical silica coating and Silanization on the YTZP surface appears to be essential to adhere this substrate to resin cements. Cleaning with isopropanol promotes weak and unstable resin adhesion.
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effect of testing methods on the bond strength of resin to zirconia alumina ceramic microtensile versus shear test
Dental Materials Journal, 2008Co-Authors: Luiz Felipe Valandro, Regina Amaral, Mutlu Ozcan, Aleska Vanderlei, Marco Antonio BottinoAbstract:This study tested the bond strength of a resin cement to a glass-infiltrated zirconia-alumina ceramic after three conditioning methods and using two test methods (shear-SBS versus microtensile-MTBS). Ceramic blocks for MTBS and ceramic disks for SBS were fabricated. Three surface conditioning (SC) methods were evaluated: (1) 110-mu m Al(2)O(3)+Silanization; (2) Chairside silica coating+Silanization: (3) Laboratory silica coating+Silanization. Following surface conditioning, the resin cement (Panavia F) was bonded to the conditioned ceramics. Although no statistically significant differences (p=0.1076) were seen between the test methods, results yielded with the different surface conditioning methods showed statistically significant differences (pSC1.). As for the interaction between the factors, two-way ANOVA showed that it was not statistically significant (p=0.1443). MTBS test resulted in predominantly mixed failure (85%), but SBS test resulted in exclusively adhesive failure. On the effects of different surface conditioning methods, chairside and laboratory tribochemical silica coating followed by Silanization showed higher bond strength results compared to those of aluminum oxide abrasion and Silanization, independent of the test method employed.
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effect of conditioning methods on the microtensile bond strength of phosphate monomer based cement on zirconia ceramic in dry and aged conditions
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Regina Amaral, Ivan Balducci, Mutlu Ozcan, Marco Antonio BottinoAbstract:The objective of this study was to evaluate the durability of bond strength between a resin cement and aluminous ceramic submitted to various surface conditioning methods. Twenty-four blocks (5 X 5 X 4 mm 3) of a glass-in filtrated zirconia-alumina ceramic (inCeram Zirconia Classic) were randomly divided into three surface treatment groups: ST1-Air-abrasion with 110-mu m Al2O3 particles + Silanization; ST2-Laboratory tribochemical silica coating method (110-mu m Al2O3, ilO-PM Silica) (Rocatec) + Silanization; ST3-Chairside tribochemical silica coating method (30-mu m SiOx) (CoJet) + Silanization. Each treated ceramic block was placed in its silicone mold with the treated surface exposed. The resin cement (Panavia F) was prepared and injected into the mold over the treated surface. Specimens were sectioned to achieve nontrimmed bar specimens (14 sp/block) that were randomly divided into two conditions: (a) Dry-microtensile test after sectioning; (b) Thermocycling (TC)-(6,000X, 5-55 degrees C) and water storage (150 days). Thus, six experimental groups were obtained (11 = 50): Gr1-ST1 + dry; Gr2-ST1 + TC. Gr3-ST2 + dry; Gr4-ST2 + TC; Gr5-ST3 + dry; Gr6ST3 + TC. After microtensile testing, the failure types were noted. ST2 (25.1 +/- 11) and ST3 (24.1 +/- 7.4) presented statistically higher bond strength (MPa) than that of STI (17.5 +/- 8) regardless of aging conditions (p <0.0001). While Gr2 revealed the lowest results (13.3 +/- 6.4), the other groups (21.7 +/- 7.4-25. 9 +/- 9.1) showed statistically no significant differences (two-way ANOVA and Tukey's test, a 0.05). The majority of the failures were mixed (82%) followed by adhesive failures (18%). Gr2 presented significantly higher incidence of ADHESIVE failures (54%) than those of other groups (p = 0.0001). Both laboratory and chairside silica coating plus Silanization showed durable bond strength. After aging, airabrasion with 110-mu m Al2O3 + Silanization showed the largest decrease indicating that aging is fundamental for bond strength testing for acid-resistant Arconia ceramics in order to estimate their long-term performance in the mouth. (c) 2007 Wiley Periodicals, Inc.
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microtensile bond strength of a resin cement to feldpathic ceramic after different etching and Silanization regimens in dry and aged conditions
Dental Materials, 2007Co-Authors: Aline Scalone Brentel, Regina Amaral, Mutlu Ozcan, Luiz Felipe Valandro, Lilian Guimaraes Alarca, Marco Antonio BottinoAbstract:Abstract Objectives This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application. Methods Thirty-two blocks (6.4 mm × 6.4 mm × 4.8 mm) were fabricated using a microparticulate feldspathic ceramic (Vita VM7), ultrasonically cleaned with water for 5 min and randomly divided into four groups, according to the type of etching agent and Silanization method: method 1, etching with 10% hydrofluoric (HF) acid gel for 1 min + Silanization; method 2, HF only; method 3, etching with 1.23% acidulated phosphate fluoride (APF) for 5 min + Silanization; method 4, APF only. Conditioned blocks were positioned in their individual silicone molds and resin cement (Panavia F) was applied on the treated surfaces. Specimens were stored in distilled water (37 °C) for 24 h prior to sectioning. After sectioning the ceramic-cement blocks in x - and y -axis with a bonded area of approximately 0.6 mm 2 , the microsticks of each block were randomly divided into two storage conditions: Dry, immediate testing; TC, thermal cycling (12,000 times) + water storage for 150 d, yielding to eight experimental groups. Microtensile bond strength tests were performed in universal testing machine (cross-head speed: 1 mm/min) and failure types were noted. Data obtained (MPa) were analyzed with three-way ANOVA and Tukey's test ( α = 0.05). Results Significant influence of the use of silane ( p p = 0.0013) and surface treatment were observed ( p = 0.0014). The highest bond strengths were achieved in both dry and thermocycled conditions when the ceramics were etched with HF acid gel and silanized (17.4 ± 5.8 and 17.4 ± 4.8 MPa, respectively). Silanization after HF acid gel and APF treatment increased the results dramatically (14.5 ± 4.2–17.4 ± 4.8 MPa) compared to non-silanized groups (2.6 ± 0.8–8.9 ± 3.1 MPa) where the failure type was exclusively (100%) adhesive between the cement and the ceramic. Significance Silanization of the feldspathic ceramic surface after APF or HF acid etching increased the microtensile bond strength results significantly, with the latter providing higher results. Long-term thermocycling and water storage did not decrease the results in silanized groups.
Luiz Felipe Valandro - One of the best experts on this subject based on the ideXlab platform.
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effects of bonding area size surface treatment and specimen configuration on the push out test for assessing bonding and stress distribution to y tzp
International Journal of Adhesion and Adhesives, 2018Co-Authors: Vinicius Felipe Wandscher, Ana Maria Estivalete Marchionatti, Aline Campos Otani, Cesar Dalmolin Bergoli, Paulo Francisco Cesar, Luiz Felipe ValandroAbstract:Abstract Purpose To evaluate the influence of specimen configuration, bonding area and zirconia surface treatment on the push out bond strength to Y-TZP and on the stress distribution using finite element analysis (FEA). Materials and methods 240 Y-TZP blocks with a central perforation were assigned to 8 groups (n=30) according to the adhesive area (macro-test: 5 × 5.5 × 4 mm and micro-test: 5 × 5.5 × 1 mm), material inserted in the perforation (resin cement or composite resin) and surface treatment (Silanization or tribochemical silica coating+Silanization). Push-out bond strength test, failure modes evaluation and FEA were performed. Results Three-way ANOVA showed that bond strength was statistically higher for composite resin (p=0.00) and for macro specimens (p=0.00). Surface treatment significantly increased the adhesion, except for ‘resin cement macro-test’ (p=0.00). Finite element analysis showed that the stresses were more homogeneously distributed at the interface of micro-specimens. Conclusion Macro-push out with composite resin or cement does not appear to be promising when evaluating adhesion to zirconia ceramics; micro-push out with composite resin filler is an adequate method; the tribochemical silica coating surface treatment can be evaluated by all tested methods in the current study, except for the macro-test with resin cement condition.
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adhesion to y tzp ceramic study of silica nanofilm coating on the surface of y tzp
Journal of Biomedical Materials Research Part B, 2015Co-Authors: Carolina Ceoli Druck, Joao Luiz Pozzobo, Gustavo Luiz Callegari, L S Dorneles, Luiz Felipe ValandroAbstract:This study evaluated the influence of silica-based film coatings on the surface of yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP), in particular on the durability of the bond strength between the ceramic and resin cement. Eighty Y-TZP (In-Ceram YZ, Vita) blocks (4 × 4 × 3 mm) were obtained and divided into four groups according to the surface treatments (n = 20): tribochemical silica coating (TBS; Cojet, 3M/ESPE), 5 nm SiO2 nanofilm and Silanization (F-5), 500 nm SiO2 nanofilm and Silanization (F-500), and 500 nm SiO2 nanofilm + hydrofluoric-acid-etching + Silanization (F-500HF). Specimens of composite resin (3.25 mm in diameter and 3 mm in height) were cemented to Y-TZP blocks using resin cement (Relyx ARC). Half of the specimens from each group were tested 24 h after adhesion (B: baseline condition), and the other half were subjected to aging (A: storage for 90 days and 10,000 thermal cycles). The specimens were subjected to shear testing (SBS) (1 mm/min). After testing, the surfaces were analyzed with a stereomicroscope and scanning electron microscope. Micromorphologic and elemental chemical analyses of the treated Y-TZP surface were made by X-ray energy dispersive spectroscopy. Bond strength data were statistically analyzed by Kruskal-Wallis/Mann-Whitney tests (α = 0.05). The surface treatment showed significant differences for B (p = 0.0001) and A (p = 0.0000) conditions. In both storage conditions, TBS and F-5 groups promoted the significantly highest bond strength. Most of the specimens presented adhesive failure. The X-ray energy dispersive spectroscopy analysis depicted the highest peak of silica in the TBS, F-5, and F-500 groups. The adhesion to zirconia can be improved if the surface receives a 5 nm layer of SiO2 nanofilm or is subjected to sandblasting with silica particles, followed by Silanization.
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adhesive quality of self adhesive and conventional adhesive resin cement to y tzp ceramic before and after aging conditions
Operative Dentistry, 2010Co-Authors: Sheila Pestana Passos, Marco Antonio Bottino, Mutlu Ozcan, Liliana Gressler May, Diana Capelli Barca, Luiz Felipe ValandroAbstract:Clinical Relevance Chairside tribochemical silica coating and Silanization on the YTZP surface appears to be essential to adhere this substrate to resin cements. Cleaning with isopropanol promotes weak and unstable resin adhesion.
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effect of testing methods on the bond strength of resin to zirconia alumina ceramic microtensile versus shear test
Dental Materials Journal, 2008Co-Authors: Luiz Felipe Valandro, Regina Amaral, Mutlu Ozcan, Aleska Vanderlei, Marco Antonio BottinoAbstract:This study tested the bond strength of a resin cement to a glass-infiltrated zirconia-alumina ceramic after three conditioning methods and using two test methods (shear-SBS versus microtensile-MTBS). Ceramic blocks for MTBS and ceramic disks for SBS were fabricated. Three surface conditioning (SC) methods were evaluated: (1) 110-mu m Al(2)O(3)+Silanization; (2) Chairside silica coating+Silanization: (3) Laboratory silica coating+Silanization. Following surface conditioning, the resin cement (Panavia F) was bonded to the conditioned ceramics. Although no statistically significant differences (p=0.1076) were seen between the test methods, results yielded with the different surface conditioning methods showed statistically significant differences (pSC1.). As for the interaction between the factors, two-way ANOVA showed that it was not statistically significant (p=0.1443). MTBS test resulted in predominantly mixed failure (85%), but SBS test resulted in exclusively adhesive failure. On the effects of different surface conditioning methods, chairside and laboratory tribochemical silica coating followed by Silanization showed higher bond strength results compared to those of aluminum oxide abrasion and Silanization, independent of the test method employed.
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microtensile bond strength of a resin cement to feldpathic ceramic after different etching and Silanization regimens in dry and aged conditions
Dental Materials, 2007Co-Authors: Aline Scalone Brentel, Regina Amaral, Mutlu Ozcan, Luiz Felipe Valandro, Lilian Guimaraes Alarca, Marco Antonio BottinoAbstract:Abstract Objectives This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application. Methods Thirty-two blocks (6.4 mm × 6.4 mm × 4.8 mm) were fabricated using a microparticulate feldspathic ceramic (Vita VM7), ultrasonically cleaned with water for 5 min and randomly divided into four groups, according to the type of etching agent and Silanization method: method 1, etching with 10% hydrofluoric (HF) acid gel for 1 min + Silanization; method 2, HF only; method 3, etching with 1.23% acidulated phosphate fluoride (APF) for 5 min + Silanization; method 4, APF only. Conditioned blocks were positioned in their individual silicone molds and resin cement (Panavia F) was applied on the treated surfaces. Specimens were stored in distilled water (37 °C) for 24 h prior to sectioning. After sectioning the ceramic-cement blocks in x - and y -axis with a bonded area of approximately 0.6 mm 2 , the microsticks of each block were randomly divided into two storage conditions: Dry, immediate testing; TC, thermal cycling (12,000 times) + water storage for 150 d, yielding to eight experimental groups. Microtensile bond strength tests were performed in universal testing machine (cross-head speed: 1 mm/min) and failure types were noted. Data obtained (MPa) were analyzed with three-way ANOVA and Tukey's test ( α = 0.05). Results Significant influence of the use of silane ( p p = 0.0013) and surface treatment were observed ( p = 0.0014). The highest bond strengths were achieved in both dry and thermocycled conditions when the ceramics were etched with HF acid gel and silanized (17.4 ± 5.8 and 17.4 ± 4.8 MPa, respectively). Silanization after HF acid gel and APF treatment increased the results dramatically (14.5 ± 4.2–17.4 ± 4.8 MPa) compared to non-silanized groups (2.6 ± 0.8–8.9 ± 3.1 MPa) where the failure type was exclusively (100%) adhesive between the cement and the ceramic. Significance Silanization of the feldspathic ceramic surface after APF or HF acid etching increased the microtensile bond strength results significantly, with the latter providing higher results. Long-term thermocycling and water storage did not decrease the results in silanized groups.
A Peral - One of the best experts on this subject based on the ideXlab platform.
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improvement of the hierarchical ts 1 properties by Silanization of protozeolitic units in presence of alcohols
Microporous and Mesoporous Materials, 2013Co-Authors: D P Serrano, R Sanz, Patricia Pizarro, A Peral, I MorenoAbstract:Abstract The synthesis of hierarchical TS-1 zeolites has been accomplished following a strategy based on the Silanization of protozeolitic units. This kind of zeolites is characterized by having a secondary porosity in the supermicro/mesopore range and, therefore, enhanced textural properties. The generation of this secondary porosity is caused by the presence of the Silanization agent, which acts as crystal growth inhibitor. However, when a high proportion of organosilane is introduced into the synthesis medium, a highly viscous gel is formed, which reduces the anchoring of the organosilane molecules onto the protozeolitic units. In order to improve the Silanization process in these conditions, a variety of alcohols (methanol, ethanol and 2-propanol) has been tested as solvents during the Silanization step. The alcohol addition increases the incorporation of the Silanization agent onto the zeolite, which is attributed to a reduction in the synthesis media viscosity. Likewise, the alcohols may also undergo grafting onto the external surface of the protozeolitic units through alkoxylation reactions, improving the crystal growth inhibitor effect of the Silanization agent. As a consequence, these materials exhibit enhanced textural properties, with a higher secondary porosity contribution, especially when ethanol is used as solvent. Hierarchical TS-1 zeolites prepared adding alcohols in the Silanization step show improved catalytic activity in 1-octene epoxidation using tert-butylhydroperoxide as oxidant, due to a higher proportion of more accessible titanium sites. Moreover, it is noteworthy that a reasonable correlation exists between the catalytic activity and the surface attributed to the secondary porosity.
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synthesis of hierarchical zsm 5 by Silanization and alkoxylation of protozeolitic units
Catalysis Today, 2011Co-Authors: D P Serrano, A Peral, Jose Maria Aguado, J M Escola, Gabriel Morales, E AbellaAbstract:Abstract Hierarchical ZSM-5 zeolite has been synthesized by means of a method involving a precrystallization stage to form the protozeolitic units, the addition and subsequent grafting of both Silanization and alkoxylation agents, and a final hydrothermal crystallization. The influence of the alkoxylation with different alcohols (methanol, ethanol, 2-propanol and n-butanol) on the properties of the final hierarchical ZSM-5 samples has been investigated. In every case, the alcohol addition increased the incorporation of the seed Silanization agent as it decreases the gel viscosity. In addition, the presence of alcohols deeply affects the physicochemical properties of the final materials. The samples prepared with 2-propanol and methanol were highly crystalline and presented improved textural properties with regard to the reference h-ZSM-5 and n-ZSM-5. In contrast, the samples obtained with ethanol and n-butanol were partially and totally X-ray amorphous, respectively. 1H and 13C-CP solid state MAS NMR spectra proved the alkoxylation of the external surface of the protozeolitic units. Catalytic cracking of LDPE pointed out the higher TOF values obtained over the hierarchical samples prepared with methanol and 2-propanol due to a right combination of accessibility and crystallinity in these materials. The differences observed among the samples prepared with alcohols were ascribed to the strong interaction produced between the Silanization agent and the linear alcohols on the surface of the protozeolitic nanounits, which form a very stable protective layer, hindering their aggregation and subsequent crystallization.
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molecular and meso and macroscopic properties of hierarchical nanocrystalline zsm 5 zeolite prepared by seed Silanization
Chemistry of Materials, 2009Co-Authors: D P Serrano, A Peral, Gabriel Morales, J Aguado, J M Rodriguez, Matthias Thommes, Jan D Epping, Bradley F ChmelkaAbstract:Surface-passivating Silanization of protozeolitic units has been shown to be an effective strategy for the preparation of ZSM-5 nanocrystals, showing a controlled aggregation degree and a hierarchical porosity. ZSM-5 zeolite materials are thus obtained with adjustable and relatively uniform mesoporosities that have a strong influence on resulting macroscopic reaction properties, especially for macromolecular reagents. The mean sizes of the nanounits and, therefore, the textural and accessibility of these materials can be varied by changing the precrystallization conditions and the concentration of the seed-Silanization agent. In addition to conventional characterization techniques, solid-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy measurements and the application of the NLDFT model to the argon adsorption isotherms have allowed both the local and the mesoscopic compositions, as well as the structures of the hierarchically porous ZSM-5 materials, to be established. The resultin...
Mutlu Ozcan - One of the best experts on this subject based on the ideXlab platform.
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adhesive quality of self adhesive and conventional adhesive resin cement to y tzp ceramic before and after aging conditions
Operative Dentistry, 2010Co-Authors: Sheila Pestana Passos, Marco Antonio Bottino, Mutlu Ozcan, Liliana Gressler May, Diana Capelli Barca, Luiz Felipe ValandroAbstract:Clinical Relevance Chairside tribochemical silica coating and Silanization on the YTZP surface appears to be essential to adhere this substrate to resin cements. Cleaning with isopropanol promotes weak and unstable resin adhesion.
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effect of testing methods on the bond strength of resin to zirconia alumina ceramic microtensile versus shear test
Dental Materials Journal, 2008Co-Authors: Luiz Felipe Valandro, Regina Amaral, Mutlu Ozcan, Aleska Vanderlei, Marco Antonio BottinoAbstract:This study tested the bond strength of a resin cement to a glass-infiltrated zirconia-alumina ceramic after three conditioning methods and using two test methods (shear-SBS versus microtensile-MTBS). Ceramic blocks for MTBS and ceramic disks for SBS were fabricated. Three surface conditioning (SC) methods were evaluated: (1) 110-mu m Al(2)O(3)+Silanization; (2) Chairside silica coating+Silanization: (3) Laboratory silica coating+Silanization. Following surface conditioning, the resin cement (Panavia F) was bonded to the conditioned ceramics. Although no statistically significant differences (p=0.1076) were seen between the test methods, results yielded with the different surface conditioning methods showed statistically significant differences (pSC1.). As for the interaction between the factors, two-way ANOVA showed that it was not statistically significant (p=0.1443). MTBS test resulted in predominantly mixed failure (85%), but SBS test resulted in exclusively adhesive failure. On the effects of different surface conditioning methods, chairside and laboratory tribochemical silica coating followed by Silanization showed higher bond strength results compared to those of aluminum oxide abrasion and Silanization, independent of the test method employed.
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effect of conditioning methods on the microtensile bond strength of phosphate monomer based cement on zirconia ceramic in dry and aged conditions
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Regina Amaral, Ivan Balducci, Mutlu Ozcan, Marco Antonio BottinoAbstract:The objective of this study was to evaluate the durability of bond strength between a resin cement and aluminous ceramic submitted to various surface conditioning methods. Twenty-four blocks (5 X 5 X 4 mm 3) of a glass-in filtrated zirconia-alumina ceramic (inCeram Zirconia Classic) were randomly divided into three surface treatment groups: ST1-Air-abrasion with 110-mu m Al2O3 particles + Silanization; ST2-Laboratory tribochemical silica coating method (110-mu m Al2O3, ilO-PM Silica) (Rocatec) + Silanization; ST3-Chairside tribochemical silica coating method (30-mu m SiOx) (CoJet) + Silanization. Each treated ceramic block was placed in its silicone mold with the treated surface exposed. The resin cement (Panavia F) was prepared and injected into the mold over the treated surface. Specimens were sectioned to achieve nontrimmed bar specimens (14 sp/block) that were randomly divided into two conditions: (a) Dry-microtensile test after sectioning; (b) Thermocycling (TC)-(6,000X, 5-55 degrees C) and water storage (150 days). Thus, six experimental groups were obtained (11 = 50): Gr1-ST1 + dry; Gr2-ST1 + TC. Gr3-ST2 + dry; Gr4-ST2 + TC; Gr5-ST3 + dry; Gr6ST3 + TC. After microtensile testing, the failure types were noted. ST2 (25.1 +/- 11) and ST3 (24.1 +/- 7.4) presented statistically higher bond strength (MPa) than that of STI (17.5 +/- 8) regardless of aging conditions (p <0.0001). While Gr2 revealed the lowest results (13.3 +/- 6.4), the other groups (21.7 +/- 7.4-25. 9 +/- 9.1) showed statistically no significant differences (two-way ANOVA and Tukey's test, a 0.05). The majority of the failures were mixed (82%) followed by adhesive failures (18%). Gr2 presented significantly higher incidence of ADHESIVE failures (54%) than those of other groups (p = 0.0001). Both laboratory and chairside silica coating plus Silanization showed durable bond strength. After aging, airabrasion with 110-mu m Al2O3 + Silanization showed the largest decrease indicating that aging is fundamental for bond strength testing for acid-resistant Arconia ceramics in order to estimate their long-term performance in the mouth. (c) 2007 Wiley Periodicals, Inc.
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evaluation of failure characteristics and bond strength after ceramic and polycarbonate bracket debonding effect of bracket base Silanization
European Journal of Ophthalmology, 2008Co-Authors: Mutlu Ozcan, K Finnema, A YbemaAbstract:The objectives of this study were to evaluate the effect of Silanization on the failure type and shear-peel bond strength (SBS) of ceramic and polycarbonate brackets, and to determine the type of failure when debonded with either a universal testing machine or orthodontic pliers. Silanized and non-silanized ceramic and polycarbonate brackets (N = 48, n = 24 per bracket type) were bonded to extracted caries-free human maxillary central incisors using an alignment apparatus under a weight of 750 g. All bonded specimens were thermocycled 1000 times (5-55 degrees C). Half of the specimens from each group were debonded with a universal testing machine (1 mm/minute) to determine the SBS and the other half by an operator using orthodontic debonding pliers. Failure types of the enamel surface and the bracket base were identified both from visual inspection and digital photographs using the adhesive remnant index (ARI) and base remnant index (BRI). As-received ceramic brackets showed significantly higher bond strength values (11.5 +/- 4.1 MPa) than polycarbonate brackets [6.3 +/- 2.7 MPa; (P = 0.0077; analysis of variance (ANOVA)]. Interaction between bracket types and Silanization was not significant (P = 0.4408). Silanization did not significantly improve the mean SBS results either for the ceramic or polycarbonate brackets (12.9 +/- 3.7 and 6.3 +/- 2.7 MPa, respectively; P = 0.4044; two-way ANOVA, Tukey-Kramer adjustment). There was a significant difference between groups in ARI scores for ceramic (P = 0.0991) but not polycarbonate (P = 0.3916; Kruskall-Wallis) brackets. BRI values did not vary significantly for ceramic (P = 0.1476) or polycarbonate (P = 0.0227) brackets. Failure type was not significantly different when brackets were debonded with a universal testing machine or with orthodontic debonding pliers. No enamel damage was observed in any of the groups.
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microtensile bond strength of a resin cement to feldpathic ceramic after different etching and Silanization regimens in dry and aged conditions
Dental Materials, 2007Co-Authors: Aline Scalone Brentel, Regina Amaral, Mutlu Ozcan, Luiz Felipe Valandro, Lilian Guimaraes Alarca, Marco Antonio BottinoAbstract:Abstract Objectives This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application. Methods Thirty-two blocks (6.4 mm × 6.4 mm × 4.8 mm) were fabricated using a microparticulate feldspathic ceramic (Vita VM7), ultrasonically cleaned with water for 5 min and randomly divided into four groups, according to the type of etching agent and Silanization method: method 1, etching with 10% hydrofluoric (HF) acid gel for 1 min + Silanization; method 2, HF only; method 3, etching with 1.23% acidulated phosphate fluoride (APF) for 5 min + Silanization; method 4, APF only. Conditioned blocks were positioned in their individual silicone molds and resin cement (Panavia F) was applied on the treated surfaces. Specimens were stored in distilled water (37 °C) for 24 h prior to sectioning. After sectioning the ceramic-cement blocks in x - and y -axis with a bonded area of approximately 0.6 mm 2 , the microsticks of each block were randomly divided into two storage conditions: Dry, immediate testing; TC, thermal cycling (12,000 times) + water storage for 150 d, yielding to eight experimental groups. Microtensile bond strength tests were performed in universal testing machine (cross-head speed: 1 mm/min) and failure types were noted. Data obtained (MPa) were analyzed with three-way ANOVA and Tukey's test ( α = 0.05). Results Significant influence of the use of silane ( p p = 0.0013) and surface treatment were observed ( p = 0.0014). The highest bond strengths were achieved in both dry and thermocycled conditions when the ceramics were etched with HF acid gel and silanized (17.4 ± 5.8 and 17.4 ± 4.8 MPa, respectively). Silanization after HF acid gel and APF treatment increased the results dramatically (14.5 ± 4.2–17.4 ± 4.8 MPa) compared to non-silanized groups (2.6 ± 0.8–8.9 ± 3.1 MPa) where the failure type was exclusively (100%) adhesive between the cement and the ceramic. Significance Silanization of the feldspathic ceramic surface after APF or HF acid etching increased the microtensile bond strength results significantly, with the latter providing higher results. Long-term thermocycling and water storage did not decrease the results in silanized groups.
