scholarly journals Influence of a Repeated Preheating Procedure on Mechanical Properties of Three Resin Composites

2015 ◽  
Vol 40 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M D'Amario ◽  
F De Angelis ◽  
M Vadini ◽  
N Marchili ◽  
S Mummolo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Microhardness ◽  
Flexural Modulus ◽  
Bending Test ◽  
Resin Composites ◽  
Three Point Bending ◽  
Main Effect ◽  
Dependent Variables ◽  
Marginal Means

SUMMARY The aim of this study was to assess the flexural strength, flexural elastic modulus and Vickers microhardness of three resin composites prepared at room temperature or cured after one or repeated preheating cycles to a temperature of 39°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium), Opallis (FGM), and Ceram X Duo (Dentsply DeTrey). For each trial, one group of specimens of each material was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 1, 10, 20, 30, or 40 preheating cycles to a temperature of 39°C in a preheating device. Ten rectangular prismatic specimens (25 × 2 × 2 mm) were prepared for each group (N=180; n=10) and subjected to a three-point bending test for flexural strength and flexural modulus evaluation. Vickers microhardness was assessed on 10 cylindrical specimens from each group (N=180; n=10). Statistical analysis showed that, regardless of the material, the number of heating cycles was not a significant factor and was unable to influence the three mechanical properties tested. However, a significant main effect of the employed material on the marginal means of the three dependent variables was detected.

THE INFLUENCE OF SiC COATING PROCESS ON THE PROPERTIES OF C/C COMPOSITES

2007 ◽  
Vol 14 (04) ◽  
pp. 817-820
Author(s):  
MIN HUANG ◽  
KE-ZHI LI ◽  
HE-JUN LI ◽  
QIAN-GANG FU ◽  
GUO-DONG SUN
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Failure Mode ◽  
Flexural Modulus ◽  
Pack Cementation ◽  
Bending Test ◽  
Carbon Composites ◽  
Coating Process ◽  
Three Point Bending ◽  
Coated Carbon

SiC coating for carbon/carbon composites was prepared by pack cementation method. The effects of coating process on the microstructure and the mechanical properties of C / C composites were analyzed by SEM and three-point bending test, respectively. As the infiltrated Si improved the interfaces bonding during the coating process, the flexural strength and flexural modulus of SiC -coated carbon/carbon composites were both increased by about 10% than the naked C / C composites. In addition, the mechanism of the change of failure mode of SiC coated C / C composites and naked C / C composites was addressed.

scholarly journals Rapid 3 s Curing: What Happens in Deep Layers of New Bulk-Fill Composites?

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 515
Author(s):  
Danijela Marovic ◽  
Matej Par ◽  
Ana Crnadak ◽  
Andjelina Sekelja ◽  
Visnja Negovetic Mandic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Raman Spectroscopy ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Degree Of Conversion ◽  
Resin Composites ◽  
Three Point Bending ◽  
Deep Layers ◽  
Light Curing ◽  
New Generation

This study assessed the influence of rapid 3 s light curing on the new generation of bulk-fill resin composites under the simulated aging challenge and depths up to 4 mm. Four bulk-fill materials were tested: two materials designed for rapid curing (Tetric PowerFill—PFILL; Tetric PowerFlow—PFLW) and two regular materials (Filtek One Bulk Fill Restorative—FIL; SDR Plus Bulk Fill Flowable—SDR). Three-point bending (n = 10) was used to measure flexural strength (FS) and flexural modulus (FM). In the 3 s group, two 2 mm thick specimens were stacked to obtain 4 mm thickness, while 2 mm-thick specimens were used for ISO group. Specimens were aged for 1, 30, or 30 + 3 days in ethanol. The degree of conversion (DC) up to 4 mm was measured by Raman spectroscopy. There was no difference between curing protocols in FS after 1 day for all materials except PFLW. FM was higher for all materials for ISO curing protocol. Mechanical properties deteriorated by increasing depth (2–4 mm) and aging. ISO curing induced higher DC for PFLW and FIL, while 3 s curing was sufficient for PFILL and SDR. The 3 s curing negatively affected FM of all tested materials, whereas its influence on FS and DC was highly material-specific.

scholarly journals Evaluation of New Hollow Sleeve Composites for Direct Post-Core Construction

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7397
Author(s):  
Shinji Yoshii ◽  
Sufyan Garoushi ◽  
Chiaki Kitamura ◽  
Pekka K. Vallittu ◽  
Lippo V. Lassila
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Resin Composite ◽  
Flexural Modulus ◽  
Accelerated Aging ◽  
Fracture Analysis ◽  
Bending Test ◽  
Outer Diameter ◽  
Fiber Post ◽  
Three Point Bending

The preset shape and diameter of a prefabricated FRC post rarely follows the anatomy of the root canal. To solve this problem, a new hollow sleeve composite (HSC) system for post-core construction was developed and characterized. A woven fiber was impregnated with two types of resins: Bis-GMA or PMMA, and rolled into cylinders with outer diameter of 2 mm and two different inner diameters, namely 1.2 or 1.5 mm. The commercial i-TFC system was used as a control. Dual-cure resin composite was injected into these sleeves. Additionally, conventional solid fiber post was used as the inner part of the sleeve. The three-point bending test was used to measure the mechanical properties of the specimens and the fracture surface was examined using an electron microscope (SEM). The HSC (1.5 mm, Bis-GMA) revealed a statistically similar flexural modulus but higher flexural strength (437 MPa) compared to i-TFC (239 MPa; ANOVA, p < 0.05). When a fiber post was added inside, all values had a tendency to increase. After hydrothermal accelerated aging, the majority of specimens showed a significant (p < 0.05) decrease in flexural strength and modulus. SEM fracture analysis confirmed that the delamination occurred at the interface between the outer and inner materials. The HSC system provided flexibility but still high mechanical values compared to the commercial system. Thus, this system might offer an alternative practical option for direct post-core construction.

scholarly journals Resin Composite Materials for Chairside CAD/CAM Restorations: A Comparison of Selected Mechanical Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Wojciech Grzebieluch ◽  
Marcin Mikulewicz ◽  
Urszula Kaczmarek
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Weibull Modulus ◽  
Resin Composite ◽  
Flexural Modulus ◽  
Bending Test ◽  
Weibull Analysis ◽  
Three Point Bending ◽  
Characteristic Strength ◽  
Cad Cam

Objective. The aim was to evaluate the flexural strength, flexural modulus, microhardness, Weibull modulus, and characteristic strength of six resin composite blocks (Grandio Blocs-GR, Tetric CAD-TE, Brilliant Crios-CR, Katana Avencia-AV, Cerasmart-CS, and Shofu Block HC-HC). Methods. Flexural strength and flexural modulus were measured using a three-point bending test and microhardness using the Vickers method. Weibull analysis was also performed. Results. The materials showed flexural strength ranging from 120.38 (HC) to 186.02 MPa (GR), flexural modulus from 8.26 (HC) to 16.95 GPa (GR), and microhardness from 70.85 (AV) to 140.43 (GR). Weibull modulus and characteristic strength ranged from 16.35 (CS) to 34.98 (TE) and from 123.45 MPa (HC) to 190.3 MPa (GR), respectively. Conclusions. GR, TE, and CR presented significantly higher flexural strength, modulus, Weibull modulus, and characteristic strength than the others.

scholarly journals Monomers used in resin composites: degree of conversion, mechanical properties and water sorption/solubility

2012 ◽  
Vol 23 (5) ◽  
pp. 508-514 ◽  
Author(s):  
Vinícius E. S. Gajewski ◽  
Carmem S. Pfeifer ◽  
Nívea R. G. Fróes-Salgado ◽  
Letícia C. C. Boaro ◽  
Roberto R. Braga
Keyword(s):  
Mechanical Properties ◽  
Water Sorption ◽  
Flexural Modulus ◽  
Triethylene Glycol ◽  
Degree Of Conversion ◽  
Resin Composites ◽  
Triethylene Glycol Dimethacrylate ◽  
Three Point Bending ◽  
Rate Of Polymerization ◽  
Urethane Dimethacrylate

The organic phase of resin composites is constituted by dimethacrylate resins, the most common monomers being the bisphenol A diglycidildimethacrylate (BisGMA), its ethoxylated version (BisEMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA). This study compared the homopolymers formed from the monomers used in restorative dental composites in terms of their degree of conversion (DC) and reaction kinetics (by near infra-red spectroscopy, n=3), mechanical properties (flexural modulus and strength in three point-bending, FM and FS, respectively, n=15), water sorption and solubility (WS and SL, respectively - ISO 4049, n=5). Materials were made photopolymerizable by the addition of camphoroquinone/dimethylamine ethyl methacrylate. TEGDMA showed the highest DC, followed by BisEMA, UDMA and BisGMA, both at 10 min and at 24h (p<0.001). UDMA showed the highest rate of polymerization, followed by TEGDMA, BisEMA and BisGMA (H0=13.254, p<0.001). UDMA and TEGDMA presented similar FM, significantly higher (p<0.001) than BisEMA and BisGMA, which in turn present statistically similar values (p>0.001). For FS, UDMA presented the highest value (p<0.001), followed by TEGDMA, then by BisEMA and BisGMA, which were statistically similar (p>0.001). BisGMA showed the highest WS, and TEGDMA and BisEMA the lowest. UDMA was statistically similar to all (H0=16.074, p<0.001). TEGDMA presented the highest SL, followed by UDMA, BisGMA and BisEMA (p<0.001). The tested homopolymers presented different behaviors in terms of polymerization kinetics, flexural properties, water sorption and solubility. Therefore, the use of copolymers is justified in order to obtain high DC and mechanical properties, as well as good resistance to water degradation.

scholarly journals Influence of Filler Loading on the Mechanical Properties of Flowable Resin Composites

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1477 ◽  
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Bogdan Bâldea ◽  
Ondine Lucaciu ◽  
Aranka Ilea ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Filler Loading ◽  
The Other ◽  
Inorganic Filler ◽  
Resin Composites ◽  
Homogeneous Type ◽  
Sem Images

The aim of this study was to evaluate the correlation between the percent of inorganic filler by weight (wt. %) and by volume (vol. %) of 11 flowable resin composites (FRCs) and their mechanical properties. To establish the correlation, the quantity of inorganic filler was determined by combustion and shape/size analyzed by SEM images. The compressive strength (CS), flexural strength (FS), and flexural modulus (FM) were determined. The CS values were between 182.87-310.38 MPa, the FS values ranged between 59.59 and 96.95 MPa, and the FM values were between 2.34 and 6.23 GPa. The percentage of inorganic filler registered values situated between 52.25 and 69.64 wt. % and 35.35 and 53.50 vol. %. There was a very good correlation between CS, FS, and FM vs. the inorganic filler by wt. % and vol. %. (R2 = 0.8899–0.9483). The highest regression was obtained for the FM values vs. vol. %. SEM images of the tested FRCs showed hybrid inorganic filler for Filtek Supreme XT (A3) and StarFlow (A2) and a homogeneous type of inorganic filler for the other investigated materials. All of the FS values were above 50 MPa, the ISO 4049/2019 limit for FRCs.

Effect of Filler Content and Waiting time Before Light-Curing on Mechanical Properties of Dual-Cured Cement

2020 ◽  
Vol 2 (1) ◽  
pp. 45-52
Author(s):  
Ana C. de Assunção Oliveira ◽  
Sandro Griza ◽  
Rafael R. de Moraes ◽  
André L. Faria-e-Silva
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Waiting Time ◽  
Filler Content ◽  
Bending Test ◽  
Resin Cements ◽  
Three Point Bending ◽  
Light Curing ◽  
Curing Procedure

Objective:: To investigate the effect of filler content and the time spent before light-curing on mechanical properties of dual-cured cement. Methods:: Experimental dual-cured resin cements were formulated with 60, 65 or 68wt% of filler. The viscosity of experimental cement was measured using a digital viscometer. Bar-shaped specimens (25 x 2 x 2 mm) were fabricated, while the light-curing was started immediately or 5 minutes after the insertion of cement into the mold (n = 7). A three-point bending test was performed and the values of flexural strength and elastic modulus were measured. The Vickers hardness of fractured specimens was measured on the surface of the cement. Data from viscosity were submitted to oneway ANOVA, while the data from mechanical properties were analyzed by two-way ANOVA. All pair-wise comparisons were performed using Tukey’s test (α = 0.05). Results:: The experimental cement with 68wt% of filler showed the highest viscosity and those with 60wt% showed the the lowest viscosity. Irrespective of the time spent before light-curing, the cement with 65wt% of filler presented the highest values of flexural strength and elastic modulus. The addition of 60wt% of filler resulted in the lowest elastic modulus, while 68wt% of filler resulted in lowest flexural strength. Regarding the hardness, the cement with 68wt% of filler showed the highest values, while there was no difference between 60 and 65wt% of filler. Conclusion:: Filler content affected the mechanical properties of the experimental cement and this effect did not depend on the waiting time before the light-curing procedure.

The Thermal Shock Resistance of Mg-PSZ/LaPO4 Ceramics

2013 ◽  
Vol 785-786 ◽  
pp. 187-190
Author(s):  
Zhong Qiu Li ◽  
Li Jie Ci ◽  
Tie Cheng Feng ◽  
Shao Yan Zhang
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Strength Degradation ◽  
Water Quenching ◽  
Bending Test ◽  
Three Point Bending ◽  
Shock Resistance ◽  
Thermal Shock Behavior

The mechanical properties and thermal shock behavior of Mg-PSZ/LaPO4 ceramics was investigated. The thermal shock resistance of the materials was evaluated by water quenching and a subsequent three-point bending test to determine the flexural strength degradation. Mg-PSZ/15LaPO4 composite showed a higher thermal shock resistance and behaved as a typical refractory. The calculation of thermal shock resistance parameters for the composites and the monolith had indicated possible explanations for the differences in thermal shock behavior.

The Effects of MgO Addtion on the Mechanical Properties and the Phase Composition of Al2O3-TiC-TiN Ceramic Materials

2012 ◽  
Vol 457-458 ◽  
pp. 3-6
Author(s):  
Yu Huan Fei ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
Ceramic Materials ◽  
Bending Test ◽  
Vickers Indentation ◽  
Volume Percent ◽  
Sintered Ceramic ◽  
Three Point Bending

Al2O3-TiN-TiC ceramic materials with different MgO content were fabricated by hot-pressing technique. The MgO volume percent was varied from 0vol% to 5vol%. Three point bending test was applied to get the flexural strength and the Vickers indentation was applied to get the Vickers hardness and the fracture toughness. The phase composition of the ceramics was analyzed by XRD. The effects of the content of MgO on the mechanical properties and the phase composition of Al2O3-TiN-TiC were investigated. The results shows that the addition of MgO can change the phase composition of the sintered ceramic materials which displayed with diverse solid solutions and intermetallic compounds. The convertion of the mechanical properties can also be explained by the XRD results.

scholarly journals Investigating the Mechanical Properties of ZrO2-Impregnated PMMA Nanocomposite for Denture-Based Applications

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1344 ◽  
Author(s):  
Saleh Zidan ◽  
Nikolaos Silikas ◽  
Abdulaziz Alhotan ◽  
Julfikar Haider ◽  
Julian Yates
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Surface Hardness ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
The Mean

Acrylic resin PMMA (poly-methyl methacrylate) is used in the manufacture of denture bases but its mechanical properties can be deficient in this role. This study investigated the mechanical properties (flexural strength, fracture toughness, impact strength, and hardness) and fracture behavior of a commercial, high impact (HI), heat-cured denture base acrylic resin impregnated with different concentrations of yttria-stabilized zirconia (ZrO2) nanoparticles. Six groups were prepared having different wt% concentrations of ZrO2 nanoparticles: 0% (control), 1.5%, 3%, 5%, 7%, and 10%, respectively. Flexural strength and flexural modulus were measured using a three-point bending test and surface hardness was evaluated using the Vickers hardness test. Fracture toughness and impact strength were evaluated using a single edge bending test and Charpy impact instrument. The fractured surfaces of impact test specimens were also observed using a scanning electron microscope (SEM). Statistical analyses were conducted on the data obtained from the experiments. The mean flexural strength of ZrO2/PMMA nanocomposites (84 ± 6 MPa) at 3 wt% zirconia was significantly greater than that of the control group (72 ± 9 MPa) (p < 0.05). The mean flexural modulus was also significantly improved with different concentrations of zirconia when compared to the control group, with 5 wt% zirconia demonstrating the largest (23%) improvement. The mean fracture toughness increased in the group containing 5 wt% zirconia compared to the control group, but it was not significant. However, the median impact strength for all groups containing zirconia generally decreased when compared to the control group. Vickers hardness (HV) values significantly increased with an increase in ZrO2 content, with the highest values obtained at 10 wt%, at 0 day (22.9 HV0.05) in dry conditions when compared to the values obtained after immersing the specimens for seven days (18.4 HV0.05) and 45 days (16.3 HV0.05) in distilled water. Incorporation of ZrO2 nanoparticles into high impact PMMA resin significantly improved flexural strength, flexural modulus, fracture toughness and surface hardness, with an optimum concentration of 3–5 wt% zirconia. However, the impact strength of the nanocomposites decreased, apart from the 5 wt% zirconia group.

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