The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Nick Silikas - One of the best experts on this subject based on the ideXlab platform.
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post irradiation hardness development chemical softening and thermal stability of bulk fill and conventional Resin Composites
Journal of Dentistry, 2015Co-Authors: Ruwaida Z. Alshali, Nesreen A. Salim, Julian D. Satterthwaite, Nick SilikasAbstract:Abstract Objectives To measure bottom/top hardness ratio of bulk-fill and conventional Resin-Composite Materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Methods Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional Resin-Composite Materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested ( n = 5). Initial and 24 h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was re-measured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t -test ( α = 0.05). Results All Materials showed significant increase of microhardness after 24 h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all Materials. All Materials showed significant decrease of microhardness after 24 h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of post-irradiation hardness development was positively correlated to the extent of ethanol softening ( R 2 = 0.89, p Conclusions Bulk-fill Resin-Composites exhibit comparable bottom/top hardness ratio to conventional Materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. Clinical significance The manufacturer recommended depth of cure of bulk-fill Resin-Composites can be reached based on the microhardness method. Characterization of the primary polymer network of a Resin-Composite Material should be considered when evaluating its stability in the aqueous oral environment.
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Post-irradiation hardness development, chemical softening, and thermal stability of bulk-fill and conventional Resin-Composites
Journal of Dentistry, 2015Co-Authors: Ruwaida Z. Alshali, Nesreen A. Salim, Julian D. Satterthwaite, Nick SilikasAbstract:Objectives: To measure bottom/top hardness ratio of bulk-fill and conventional Resin-Composite Materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Methods: Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional Resin-Composite Materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested (n = 5). Initial and 24 h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was remeasured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t-test (α = 0.05). Results: All Materials showed significant increase of microhardness after 24 h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all Materials. All Materials showed significant decrease of microhardness after 24 h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of postirradiation hardness development was positively correlated to the extent of ethanol softening (R2= 0.89, p < 0.001). Initial thermal decomposition temperature assessed by TGA was variable and was correlated to ethanol softening. Conclusions: Bulk-fill Resin-Composites exhibit comparable bottom/top hardness ratio to conventional Materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. Clinical significance: The manufacturer recommended depth of cure of bulk-fill Resin-Composites can be reached based on the microhardness method. Characterization of the primary polymer network of a Resin-Composite Material should be considered when evaluating its stability in the aqueous oral environment.
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Nanoindentation creep versus bulk compressive creep of dental Resin-Composites
Dental Materials, 2012Co-Authors: S. El-safty, R. Akhtar, Nick Silikas, D. C. WattsAbstract:Objectives: To evaluate nanoindentation as an experimental tool for characterizing the viscoelastic time-dependent creep of Resin-Composites and to compare the resulting parameters with those obtained by bulk compressive creep. Methods: Ten dental Resin-Composites: five conventional, three bulk-fill and two flowable were investigated using both nanoindentation creep and bulk compressive creep methods. For nano creep, disc specimens (15 mm × 2 mm) were prepared from each Material by first injecting the Resin-Composite paste into metallic molds. Specimens were irradiated from top and bottom surfaces in multiple overlapping points to ensure optimal polymerization using a visible light curing unit with output irradiance of 650 mW/cm 2. Specimens then were mounted in 3 cm diameter phenolic ring forms and embedded in a self-curing polystyrene Resin. Following grinding and polishing, specimens were stored in distilled water at 37 °C for 24 h. Using an Agilent Technologies XP nanoindenter equipped with a Berkovich diamond tip (100 nm radius), the nano creep was measured at a maximum load of 10 mN and the creep recovery was determined when each specimen was unloaded to 1 mN. For bulk compressive creep, stainless steel split molds (4 mm × 6 mm) were used to prepare cylindrical specimens which were thoroughly irradiated at 650 mW/cm 2 from multiple directions and stored in distilled water at 37 °C for 24 h. Specimens were loaded (20 MPa) for 2 h and unloaded for 2 h. One-way ANOVA, Levene's test for homogeneity of variance and the Bonferroni post hoc test (all at p ≤ 0.05), plus regression plots, were used for statistical analysis. Results: Dependent on the type of Resin-Composite Material and the loading/unloading parameters, nanoindentation creep ranged from 29.58 nm to 90.99 nm and permanent set ranged from 8.96 nm to 30.65 nm. Bulk compressive creep ranged from 0.47% to 1.24% and permanent set ranged from 0.09% to 0.38%. There was a significant (p = 0.001) strong positive non-linear correlation (r 2 = 0.97) between bulk creep and nano creep that could also be expressed via a simple fractional-power function. A significant (p = 0.003) positive linear correlation (r 2 = 0.69) existed between nano creep recovery and bulk creep recovery. With both methods of examination, except for Venus Bulk Fill™ (VB), the flowable and bulk-fill Resin-Composites exhibited creep within the range exhibited by the conventional Resin-Composites. Significance: Despite the differences in loading and unloading conditions, in both methods of examination the correlation observed between the creep and recovery responses for a set of Resin-Composites was high. Both nano creep and recovery positively correlated with loading and unloading rates, respectively. © 2012 Academy of Dental Materials.
Saiji Shimoe - One of the best experts on this subject based on the ideXlab platform.
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Shear bond strength of Resin Composite veneering Material to gold alloy with varying metal surface preparations
Journal of Prosthetic Dentistry, 2001Co-Authors: Hideo Matsumura, Naomi Tanoue, Hiroaki Yanagida, Mitsuru Atsuta, Saiji ShimoeAbstract:Abstract Statement of Problem. Although adequate surface preparation is indispensable to achieve a consistent and durable bond between Resin Composite Materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. Purpose. The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic Resin Composite veneering Material and a gold casting alloy. Material and Methods. Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic Resin Composite Material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. Results. All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. Conclusion. The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and Resin Composite Material tested. (J Prosthet Dent 2001;86:315-9.)
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Shear bond strength of Resin Composite veneering Material to gold alloy with varying metal surface preparations
Journal of Prosthetic Dentistry, 2001Co-Authors: Hideo Matsumura, M.c Atsuta, Naomi Tanoue, Hiroaki Yanagida, Saiji ShimoeAbstract:Statement of problem. Although adequate surface preparation is indispensable to achieve a consistent and durable bond between Resin Composite Materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. Purpose. The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic Resin Composite veneering Material and a gold casting alloy. Material and methods. Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic Resin Composite Material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. Results. All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. Conclusion. The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and Resin Composite Material tested.
Ruwaida Z. Alshali - One of the best experts on this subject based on the ideXlab platform.
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post irradiation hardness development chemical softening and thermal stability of bulk fill and conventional Resin Composites
Journal of Dentistry, 2015Co-Authors: Ruwaida Z. Alshali, Nesreen A. Salim, Julian D. Satterthwaite, Nick SilikasAbstract:Abstract Objectives To measure bottom/top hardness ratio of bulk-fill and conventional Resin-Composite Materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Methods Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional Resin-Composite Materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested ( n = 5). Initial and 24 h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was re-measured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t -test ( α = 0.05). Results All Materials showed significant increase of microhardness after 24 h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all Materials. All Materials showed significant decrease of microhardness after 24 h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of post-irradiation hardness development was positively correlated to the extent of ethanol softening ( R 2 = 0.89, p Conclusions Bulk-fill Resin-Composites exhibit comparable bottom/top hardness ratio to conventional Materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. Clinical significance The manufacturer recommended depth of cure of bulk-fill Resin-Composites can be reached based on the microhardness method. Characterization of the primary polymer network of a Resin-Composite Material should be considered when evaluating its stability in the aqueous oral environment.
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Post-irradiation hardness development, chemical softening, and thermal stability of bulk-fill and conventional Resin-Composites
Journal of Dentistry, 2015Co-Authors: Ruwaida Z. Alshali, Nesreen A. Salim, Julian D. Satterthwaite, Nick SilikasAbstract:Objectives: To measure bottom/top hardness ratio of bulk-fill and conventional Resin-Composite Materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Methods: Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional Resin-Composite Materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested (n = 5). Initial and 24 h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was remeasured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t-test (α = 0.05). Results: All Materials showed significant increase of microhardness after 24 h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all Materials. All Materials showed significant decrease of microhardness after 24 h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of postirradiation hardness development was positively correlated to the extent of ethanol softening (R2= 0.89, p < 0.001). Initial thermal decomposition temperature assessed by TGA was variable and was correlated to ethanol softening. Conclusions: Bulk-fill Resin-Composites exhibit comparable bottom/top hardness ratio to conventional Materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. Clinical significance: The manufacturer recommended depth of cure of bulk-fill Resin-Composites can be reached based on the microhardness method. Characterization of the primary polymer network of a Resin-Composite Material should be considered when evaluating its stability in the aqueous oral environment.
Yong Hua Sheng - One of the best experts on this subject based on the ideXlab platform.
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Study on Application of Carbon Fiber Strengthen Thermoplastic Resin Composite Material
Applied Mechanics and Materials, 2014Co-Authors: Yong Hua ShengAbstract:Recently, as the development of thermoplastic Resin with excellent property and forming process of thermoplastic Resin Composite Material, research of thermoplastic Resin becomes a hot issue in related areas. Comparing with common Composite Material, thermoplastic Resin Composite Material has many advantages, such as, excellent impacting resistance and many processes. So, more and more researchers focus in thermoplastic Resin Composite Material. In this article, applications of carbon fiber strengthen thermoplastic Resin Composite Materials are comprehensive.
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Different Content of Short Carbon Fiber Influence on the Hardness of Thermo Plastic Resin Composite Material
Applied Mechanics and Materials, 2014Co-Authors: Yong Hua ShengAbstract:Using screw injecting molding method to prepare the short fiber strengthening thermo plastic Resin Composite Material, using short carbon fiber as strengthening Material and polytene Resin as matrix. Study different influence of carbon fiber content to the hardness of short fiber strengthening thermo plastic Resin Composite Material. The result shows that the hardness of short carbon fiber strengthening thermo Resin Composite Material increase as increasing the short carbon fiber content.
Hideo Matsumura - One of the best experts on this subject based on the ideXlab platform.
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Shear bond strength of Resin Composite veneering Material to gold alloy with varying metal surface preparations
Journal of Prosthetic Dentistry, 2001Co-Authors: Hideo Matsumura, Naomi Tanoue, Hiroaki Yanagida, Mitsuru Atsuta, Saiji ShimoeAbstract:Abstract Statement of Problem. Although adequate surface preparation is indispensable to achieve a consistent and durable bond between Resin Composite Materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. Purpose. The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic Resin Composite veneering Material and a gold casting alloy. Material and Methods. Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic Resin Composite Material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. Results. All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. Conclusion. The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and Resin Composite Material tested. (J Prosthet Dent 2001;86:315-9.)
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Shear bond strength of Resin Composite veneering Material to gold alloy with varying metal surface preparations
Journal of Prosthetic Dentistry, 2001Co-Authors: Hideo Matsumura, M.c Atsuta, Naomi Tanoue, Hiroaki Yanagida, Saiji ShimoeAbstract:Statement of problem. Although adequate surface preparation is indispensable to achieve a consistent and durable bond between Resin Composite Materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. Purpose. The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic Resin Composite veneering Material and a gold casting alloy. Material and methods. Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic Resin Composite Material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. Results. All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. Conclusion. The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and Resin Composite Material tested.