“…This might attribute to the different in nature of matrix. The differences between solubility parameter [(cal/cm 3 ) 1/2 ] of MPS according the manufacturer's information (9.48) and urethane dimethacrylate (5.18) 20) used in the previous study was greater than between MPS and MMA (8.75) 18) in this study. Moreover, silane absorbed on Al2O3 in aqueous solution was weaker than SiO2 21) .…”
This study evaluated the different amounts of 3-methacryloxypropyltrimethoxysilane (MPS) coated alumina fi ller particles on fl exural strength and wear resistance of alumina reinforced polymethyl methacrylate (PMMA) denture base. Ten mass% of alumina fi ller silanized with 0, 0.1, 0.2, or 0.4 mass% of MPS was blended with PMMA. PMMA without alumina particles served as control. Specimens were prepared for fl exural strength and wear resistance tests (n=10). Flexural strength was determined using a 3-point bending test and volume loss was measured by in-vitro 2-body wear-testing. The results were analyzed by One-way ANOVA and Tamhane's test (α=0.05). Flexural strength ranged from 95.1-117.8 MPa, while volume loss ranged from 0.038-0.160 mm 3 . Statistical analysis indicated the 0.1 mass% MPS silanized group had signifi cantly higher fl exural strength and lower volume loss than the control group. Adding alumina fi ller silanized with 0.1 mass% MPS resulted in an improvement of the fl exural strength and wear resistance of PMMA.
“…This might attribute to the different in nature of matrix. The differences between solubility parameter [(cal/cm 3 ) 1/2 ] of MPS according the manufacturer's information (9.48) and urethane dimethacrylate (5.18) 20) used in the previous study was greater than between MPS and MMA (8.75) 18) in this study. Moreover, silane absorbed on Al2O3 in aqueous solution was weaker than SiO2 21) .…”
This study evaluated the different amounts of 3-methacryloxypropyltrimethoxysilane (MPS) coated alumina fi ller particles on fl exural strength and wear resistance of alumina reinforced polymethyl methacrylate (PMMA) denture base. Ten mass% of alumina fi ller silanized with 0, 0.1, 0.2, or 0.4 mass% of MPS was blended with PMMA. PMMA without alumina particles served as control. Specimens were prepared for fl exural strength and wear resistance tests (n=10). Flexural strength was determined using a 3-point bending test and volume loss was measured by in-vitro 2-body wear-testing. The results were analyzed by One-way ANOVA and Tamhane's test (α=0.05). Flexural strength ranged from 95.1-117.8 MPa, while volume loss ranged from 0.038-0.160 mm 3 . Statistical analysis indicated the 0.1 mass% MPS silanized group had signifi cantly higher fl exural strength and lower volume loss than the control group. Adding alumina fi ller silanized with 0.1 mass% MPS resulted in an improvement of the fl exural strength and wear resistance of PMMA.
“…The presence of UDMA and, more importantly, Bis-Hema, makes this composite more color stable and more hydrophobic. 19,20 This more hydrophobic characteristic could explain the fact that, in this study, mustard was the substance that promoted the greatest staining. This condiment is composed of vinegar, mustard, corn, sugar, salt, food flavoring, conservative and curcuma, which is a rhizome extensively used in industry to obtain food coloring and pharmaceutical products.…”
Composite resins might be susceptible to degradation and staining when in contact with some foods and drinks. This study evaluated color alteration and changes in microhardness of a microhybrid composite after immersion in different colored foods and determined whether there was a correlation between these two variables. Eighty composite disks were randomly divided into 8 experimental groups (n = 10): kept dry; deionized water; orange juice; passion fruit juice; grape juice; ketchup; mustard and soy sauce. The disks were individually immersed in their respective test substance at 37 ºC, for a period of 28 days. Superficial analysis of the disk specimens was performed by taking microhardness measurements (Vickers, 50 g load for 45 seconds) and color alterations were determined with a spectrophotometer (CINTRA 10-using a CIEL*a*b* system, 400-700 nm wavelength, illuminant d65 and standard observer of 2º) at the following times: baseline (before immersion), 1, 7, 14, 21 and 28 days. Results were analyzed by ANOVA and Tukey's test (p < 0.05). Both variables were also submitted to Pearson's correlation test (p < 0.05). The passion fruit group underwent the greatest microhardness change, while the mustard group suffered the greatest color alteration. Significant positive correlation was found between the two variables for the groups deionized water, grape juice, soy sauce and ketchup. Not all color alteration could be associated with surface degradation.
“…In the process, ethoxylated bisphenol-A (BisEMA), a non-hydroxylated monomer, was developed. Compared to BisGMA, BisEMA is less hydrophilic and exhibits a reduced viscosity 20 .…”
Section: Introductionmentioning
confidence: 99%
“…The BisGMA monomer contains pendant hydroxyl groups within its molecular backbone 20 . Due to these polar groups, polymers made with this monomer tend to be somewhat hydrophilic and susceptible to increased water sorption 21 .…”
Section: Introductionmentioning
confidence: 99%
“…Due to these polar groups, polymers made with this monomer tend to be somewhat hydrophilic and susceptible to increased water sorption 21 . Various methods have been employed in order to reduce the hydrophilicity of BisGMA-based composites 20 . In the process, ethoxylated bisphenol-A (BisEMA), a non-hydroxylated monomer, was developed.…”
The influence of curing tip distance and storage time on the hardness of a composite was evaluated. Composite samples (Filtek Z250) were polymerized at different distances (5, 10, and 15 mm), compared with a control group (0 mm), and stored in distilled water at 37 ° C for 24 hours. The Knoop-hardness of top and bottom surfaces was assessed (25 g/30 s). Specimens were stored in distilled water for 6 and 12 months and were retested. Hardness was found to be negatively influenced by both curing tip distance and storage time. Despite similar values at 24 hours, differences in hardness values compared with the control group appeared over time. In comparing both surfaces, hardness proved to be greater at the top surface for all groups. Composites with similar initial hardness values can degrade very differently after water storage. The higher the photoactivation distance and storage time, the worse the mechanical property.
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