The Experts below are selected from a list of 1881 Experts worldwide ranked by ideXlab platform
Ailin Mahdkhah - One of the best experts on this subject based on the ideXlab platform.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of clinical and experimental dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of Clinical and Experimental Dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:Background The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Material and Methods Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. Results The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Conclusions Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.
Mohammad Ansarin - One of the best experts on this subject based on the ideXlab platform.
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Effect of pre-heating on the mechanical properties of silorane-based and methacrylate-based composites
Journal of Clinical and Experimental Dentistry, 2016Co-Authors: Narmin Mohammadi, Mahmoud Bahari, Soodabeh Kimyai, Elmira Jafari-navimipour, Amir Ahmad Ajami, Mohammad AnsarinAbstract:BACKGROUND The use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. MATERIAL AND METHODS A Silorane-based (Silorane) and a Methacrylate-based (Z250) composite were preheated to different temperatures (25, 37, and 68 °C) and afterwards were tested with the appropriate devices for each testing protocol. The material's flexural strength, elastic modulus, and Vickers microhardness were evaluated. Two-way ANOVA, and Tukey's post hoc were used to analyze the data. RESULTS Microhardness and elastic modulus increased with preheating, while flexural strength values did not increase significantly with preheating. Furthermore the methacrylate-based composite (Z250) showed higher values compared to the Silorane-based composite (Silorane) in all the tested properties. CONCLUSIONS Preheating Silorane enhances the composite's microhardness and elastic modulus but does not affect its flexural strength. On the other hand, preheating Z250 increases its microhardness but does not change its flexural strength or elastic modulus. In addition, the Z250 composite shows higher microhardness and flexural strength than Silorane, but the elastic modulus values with preheating are similar. Therefore Z250 seems to have better mechanical properties making it the better choice in a clinical situation. Key words:Composite, elastic modulus, flexural strength, microhardness, preheating.
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Effect of pre-heating on the mechanical properties of silorane-based and methacrylate-based composites.
Journal of clinical and experimental dentistry, 2016Co-Authors: Narmin Mohammadi, Mahmoud Bahari, Soodabeh Kimyai, Elmira Jafari-navimipour, Amir Ahmad Ajami, Mohammad AnsarinAbstract:The use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. A Silorane-based (Silorane) and a Methacrylate-based (Z250) composite were preheated to different temperatures (25, 37, and 68 °C) and afterwards were tested with the appropriate devices for each testing protocol. The material's flexural strength, elastic modulus, and Vickers microhardness were evaluated. Two-way ANOVA, and Tukey's post hoc were used to analyze the data. Microhardness and elastic modulus increased with preheating, while flexural strength values did not increase significantly with preheating. Furthermore the methacrylate-based composite (Z250) showed higher values compared to the Silorane-based composite (Silorane) in all the tested properties. Preheating Silorane enhances the composite's microhardness and elastic modulus but does not affect its flexural strength. On the other hand, preheating Z250 increases its microhardness but does not change its flexural strength or elastic modulus. In addition, the Z250 composite shows higher microhardness and flexural strength than Silorane, but the elastic modulus values with preheating are similar. Therefore Z250 seems to have better mechanical properties making it the better choice in a clinical situation. Key words:Composite, elastic modulus, flexural strength, microhardness, preheating.
Kurunthachalam Kannan - One of the best experts on this subject based on the ideXlab platform.
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survey of cyclic and linear siloxanes in sediment from the songhua river and in sewage sludge from wastewater treatment plants northeastern china
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Kurunthachalam Kannan, Zifeng Zhang, Nanqi Ren, Dawen GaoAbstract:Siloxanes are used in a wide range of industrial applications, such as fuel additives, automotive polishes and waxes, and antifoaming agents, as well as in personal care products and biomedical devices. Despite the potential for environmental occurrence, few studies have reported sources and pathways of siloxanes in the environment. In this study, we determined concentrations of four cyclic siloxanes, namely, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), and tetradecamethylcycloheptasiloxane (D7) as well as 13 linear siloxanes (L4 to L16), in sediments sampled from the Songhua River and in sewage sludge sampled from treatment plants that discharge wastewater into the Songhua River in northeastern China. Siloxanes were found in all of the sediment samples at total concentrations (sum of all cyclic and linear siloxanes) as high as 2050 ng/g dry weight (dw). The respective total concentration ranges for cyclic (D4, D5, D6, and D7) and linear (L4 to L16) siloxanes in sewage sludge were 602 to 2360 and 98 to 3310 ng/g dw. Cyclic siloxanes were found at greater concentrations than linear siloxanes in sediment samples. However, the summed concentrations of linear siloxanes were higher than the summed concentrations of cyclic siloxanes in sludge samples. Among cyclic siloxanes, D7 and D5 were the dominant compounds in both sediment and sludge. Among linear siloxanes, L10 and L11 together accounted for 55% of the total concentrations in sludge samples, and L6 accounted for 30% of the total concentration in sediment samples. To our knowledge, this is the first report to document concentrations and compositions of organosiloxanes in sediments and sewage sludge from China.
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survey of organosilicone compounds including cyclic and linear siloxanes in personal care and household products
Archives of Environmental Contamination and Toxicology, 2008Co-Authors: Yuichi Horii, Kurunthachalam KannanAbstract:The determination of organosiloxanes in consumer products is important for the evaluation and characterization of sources of human and environmental exposures. In this study, we determined concentrations of cyclic siloxanes [octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6)], tetradecamethylcycloheptasiloxane (D7)] and linear siloxanes (L4 to L14) in a variety of consumer products (n = 76), including hair-care products, skin lotions, body washes, cosmetics, nursing nipples (i.e., pacifiers), cookware, and household sanitation products such as cleansers and furniture polishes, using gas chromatography–mass spectrometry with selected ion monitoring. Prior to the analysis of samples, a method was developed to reduce the contamination arising from organosiloxanes present in certain gas chromatograph (GC) parts, such as the inlet septum; use of a Restek BTO septum at an inlet temperature of 200°C gave the lowest background level (D4: 0.8 pg; D5: 0.3 pg; D6: 0.2 pg). Concentrations of cyclic siloxanes in consumer products analyzed ranged from <0.35 to 9380 μg/g, from <0.39 to 81,800 μg/g, from <0.33 to 43,100 μg/g, and from <0.42 to 846 μg/g for D4, D5, D6, and D7, respectively. Concentrations of linear siloxanes varied from <0.059 to 73,000 μg/g. More than 50% of the samples analyzed contained D4, D5, or D6. Cyclic siloxanes were predominant in most of the sample categories; D5 was predominant in hair-care products, skin lotions, and cosmetics; D6 or D7 was predominant in rubber products, including nipples, cookware, and sealants. Potential daily exposure to total organosiloxanes (sum of cyclic and linear siloxanes) from the use of personal-care products by adult women in the United States has been estimated to be 307 mg. Significant positive correlations (p < 0.01) existed in our study between D4 and D7, D4 and linear siloxanes, D5 and D6, and D5 and linear siloxanes. The correlations can be related to the composition of organosiloxanes used in consumer products. The results of our study suggest that a wide variety of consumer products that are used on a daily basis contain cyclic and linear siloxanes and these products can contribute considerably to human exposures.
Farnoosh Fallahzadeh - One of the best experts on this subject based on the ideXlab platform.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of clinical and experimental dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of Clinical and Experimental Dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:Background The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Material and Methods Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. Results The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Conclusions Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.
Shirin Ghasemi - One of the best experts on this subject based on the ideXlab platform.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of clinical and experimental dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.
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Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.
Journal of Clinical and Experimental Dentistry, 2018Co-Authors: Farnoosh Fallahzadeh, Mohammad Atai, Shirin Ghasemi, Ailin MahdkhahAbstract:Background The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel. Material and Methods Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing. Each group was further divided into three subgroups according to their rinsing time. Then a cylinder of the composite was bonded to the enamel and Shear bond strength was assessed. To determine the failure mode, the bonded surfaces were then observed under SEM. In addition, the DC of each group was measured at pH levels of 4 and 7 using FTIR spectroscopy. The data were analyzed with one-way ANOVA and post hoc analysis followed by Fisher's least significant difference. Results The bond strength of the non-contaminated methacrylate group was significantly higher than the other groups (p< 0.0001). In addition, there was no significant deference between the methacrylate subgroups. In the silorane groups, the shear bond strength was higher in the rinsing time of 15 seconds. Failure pattern was mainly adhesive. The DC of the Methacrylates had no significant difference at pH 4 and pH 7, but was significantly higher than that of Siloranes (p< 0.0001). While the DC of the Siloranes at pH 4 was significantly higher than at pH 7 (p< 0.0001). Conclusions Saliva contamination in both composites reduces bond strength. Increasing rinsing time in Methacrylates proves ineffective. In non-contaminated Siloranes, excessive rinsing time reduced bond strength. The best-recommended rinsing time for both composite is 15 seconds. Key words:Composite resins, silorane composite resin, methacrylates, shear strength.