scholarly journals Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

2017 ◽  
Vol 28 (6) ◽  
pp. 726-730 ◽  
Author(s):  
Caio Vinícius Signorelli Grohmann ◽  
Eveline Freitas Soares ◽  
Eduardo José Carvalho Souza-Junior ◽  
William Cunha Brandt ◽  
Regina Maria Puppin-Rontani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Tertiary Amine ◽  
Water Sorption ◽  
Water Solubility ◽  
Distilled Water ◽  
Resin Composites ◽  
Amine Concentration ◽  
One Way Anova

Abstract The aim in this study was to evaluate the influence of different ratio of camphorquinone/tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey’s test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites

scholarly journals Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Water Sorption ◽  
Water Solubility ◽  
Flexural Modulus ◽  
Manufacturing Method ◽  
Heat Curing ◽  
Significant Difference ◽  
Cad Cam ◽  
Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

scholarly journals Flexural Properties and Elastic Modulus of Different Esthetic Restorative Materials: Evaluation after Exposure to Acidic Drink

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Andrea Scribante ◽  
Marco Bollardi ◽  
Marco Chiesa ◽  
Claudio Poggio ◽  
Marco Colombo
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Water Immersion ◽  
Testing Machine ◽  
Distilled Water ◽  
Resin Composites ◽  
Restorative Material ◽  
Universal Testing ◽  
Restorative Materials ◽  
Acidic Beverages

Background. Acidic beverages, such as soft drinks, can produce erosion of resin composites. The purpose of the present study was to investigate mechanical properties of different esthetic restorative materials after exposure to acidic drink. Methods. Nine different composites were tested: nanofilled (Filtek Supreme XTE, 3M ESPE), microfilled hybrid (G-ænial, GC Corporation), nanohybrid Ormocer (Admira Fusion, Voco), microfilled (Gradia Direct, GC Corporation), microfilled hybrid (Essentia, GC Corporation), nanoceramic (Ceram.X Universal, Dentsply De Trey), supranano spherical hybrid (Estelite Asteria, Tokuyama Dental Corporation), flowable microfilled hybrid (Gradia Direct Flo, GC Corporation), and bulk fill flowable (SureFil SDR flow, Dentsply De Trey). Thirty specimens of each esthetic restorative material were divided into 3 subgroups (n=10): specimens of subgroup 1 were used as control, specimens of subgroup 2 were immersed in 50 ml of Coca Cola for 1 week, and specimens of subgroup 3 were immersed in 50 ml of Coca Cola for 1 month. Flexural strength and elastic modulus were measured for each material with an Instron Universal Testing Machine. Data were submitted to statistical analysis. Results. After distilled water immersion, nanofilled composite showed the highest value of both flexural strength and elastic modulus, but its flexural values decreased after acidic drink immersion. No significant differences were reported between distilled water and acidic drink immersion for all other materials tested both for flexural and for elastic modulus values. Conclusions. Even if nanofilled composite showed highest results, acidic drink immersion significantly reduced flexural values.

scholarly journals Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites

2017 ◽  
Vol 42 (6) ◽  
pp. E177-E187 ◽  
Author(s):  
S Shibasaki ◽  
T Takamizawa ◽  
K Nojiri ◽  
A Imai ◽  
A Tsujimoto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Resin Composite ◽  
High Viscosity ◽  
The Other ◽  
Light Irradiation ◽  
Volumetric Shrinkage ◽  
Resin Composites ◽  
Polymerization Shrinkage

SUMMARY The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m3. There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and polymerization kinetics of these categories of current resin composite.

scholarly journals 3D-Printed vs. Heat-Polymerizing and Autopolymerizing Denture Base Acrylic Resins

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5781
Author(s):  
Leila Perea-Lowery ◽  
Mona Gibreel ◽  
Pekka K. Vallittu ◽  
Lippo V. Lassila
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Water Solubility ◽  
Base Material ◽  
Acrylic Resin ◽  
Denture Base ◽  
3D Printed ◽  
Work Of Fracture

The aim of this work was to investigate the effect of two post-curing methods on the mechanical properties of a 3D-printed denture base material. Additionally, to compare the mechanical properties of that 3D-printed material with those of conventional autopolymerizing and a heat-cured denture base material. A resin for 3D-printing denture base (Imprimo®), a heat-polymerizing acrylic resin (Paladon® 65), and an autopolymerizing acrylic resin (Palapress®) were investigated. Flexural strength, elastic modulus, fracture toughness, work of fracture, water sorption, and water solubility were evaluated. The 3D-printed test specimens were post-cured using two different units (Imprimo Cure® and Form Cure®). The tests were carried out after both dry and 30 days water storage. Data were collected and statistically analyzed. Resin type had a significant effect on the flexural strength, elastic modulus, fracture toughness, and work of fracture (p < 0.001). The flexural strength and elastic modulus for the heat-cured polymer were significantly the highest among all investigated groups regardless of the storage condition (p < 0.001). The fracture toughness and work of fracture of the 3D-printed material were significantly the lowest (p < 0.001). The heat-cured polymer had the lowest significant water solubility (p < 0.001). The post-curing method had an impact on the flexural strength of the investigated 3D-printed denture base material. The flexural strength, elastic modulus, fracture toughness, work of fracture of the 3D-printed material were inferior to those of the heat-cured one. Increased post-curing temperature may enhance the flexural properties of resin monomers used for 3D-printing dental appliances.

scholarly journals Examining the Effect of Radiant Exposure on Commercial Photopolimerizable Dental Resin Composites

2018 ◽  
Vol 6 (4) ◽  
pp. 55 ◽  
Author(s):  
Carlos Cuevas-Suárez ◽  
Belinda Pimentel-García ◽  
Alejandro Rivera-Gonzaga ◽  
Carlos Álvarez-Gayosso ◽  
Adriana Ancona-Meza ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Water Sorption ◽  
Water Solubility ◽  
Light Exposure ◽  
Physical And Mechanical Properties ◽  
Degree Of Conversion ◽  
Resin Composites ◽  
Dental Resin ◽  
Radiant Exposure ◽  
Dental Resin Composites

The objective of this study was to evaluate the effect of radiant exposure on the chemical and physical properties of four commercial dental resin composites. The four dental resin composites used were Kalore, Admira, Tetric N-Ceram Bulk Fill, and Filtek Z350 XT. The composites were subjected to three curing protocols: 1000 mW/cm2 for 5 s, 1000 mW/cm2 for 10 s, and 400 mW/cm2 for 25 s. The flexural strength, elastic modulus, water sorption, water solubility, degree of conversion, and polymerization shrinkage were evaluated. The results were analyzed by means of ANOVA and Tukey tests. For Admira and Kalore, significant differences between light exposure protocols were observed for the elastic modulus (p < 0.001), which was higher when a higher amount of radiant exposure was used. For Filtek Z350, differences were only observed for the degree of conversion (p < 0.001), and a higher amount of radiant exposure allowed us to obtain higher values. The Tetric N-Ceram Bulk Fill analysis showed significant differences for the elastic modulus and water sorption (p < 0.001), and specimens that had been subject to a radiant exposure of 10 J/cm2 showed a higher elastic modulus. In most cases, the physical and mechanical properties analyzed were not affected by different radiant exposure values. Other resin-based composite (RBC) characteristics seem to have a greater influence on material properties.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

scholarly journals Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2769
Author(s):  
Jonne Oja ◽  
Lippo Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan Garoushi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Accelerated Aging ◽  
Wear Depth ◽  
Resin Composites ◽  
Expiration Date ◽  
Dental Resin ◽  
Hydrothermal Aging ◽  
Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

scholarly journals Effects of Polymerization Mode and Interaction with Hydroxyapatite on the Rate of pH Neutralization, Mechanical Properties, and Depth of Cure in Self-Adhesive Cements

2019 ◽  
Vol 13 (02) ◽  
pp. 178-186
Author(s):  
Fabiana S. A. S. Camargo ◽  
Alejandra H. M. González ◽  
Roberta C. B. Alonso ◽  
Vinicius Di Hipólito ◽  
Paulo H. P. D'Alpino
Keyword(s):  
Mechanical Properties ◽  
Infrared Spectroscopy ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
The Self ◽  
Chemical Bonds ◽  
Resin Cements ◽  
Adhesive Resin ◽  
Depth Of Cure ◽  
Ph Neutralization

Abstract Objective The aim of the study was to evaluate the physicochemical properties of self-adhesive resin cements associated with hydroxyapatite (HAp) according to the polymerization activation. Materials and Methods Specimens of cements (PermaCem 2.0 [DMG]; MaxCem Elite [Kerr], and RelyX U200 [3M ESPE]) were distributed into three groups: activation mode; self-cured and dual-cured modes; and association or not with HAp powder mode. The pH neutralization was evaluated as a function of time. Flexural strength and elastic modulus were also tested (0.5 mm/min.). The depth of cure was also analyzed using the scraping test (ISO 4049). Infrared spectroscopy was also used to collect the spectra of specimens to evaluate the chemical bonds. Statistical comparisons were conducted at 5% of significance. Results The aggressiveness of the self-adhesive resin cements evaluated varied among the materials with a tendency for neutralization. Self-cure groups exhibited lower pH throughout the entire evaluation when compared with that of the dual-cure ones, irrespective of the addition of HAp. MaxCem Elite when photoactivated was the only cement influenced by the addition of the HAp in terms of mechanical properties. The self-adhesive cements tested presented equivalent depth of cure based on the ISO 4049 requirements, regardless of the evaluated factors. Conclusions Based on the parameters evaluated, the results demonstrated that most of the self-adhesive cements remained unaltered or improved when mixed with HAp, regardless of the activation mode.

Evaluation of Relations among Basic Mechanical Properties of Concrete with Machine-Made Sand

2011 ◽  
Vol 418-420 ◽  
pp. 441-444 ◽  
Author(s):  
Feng Lan Li ◽  
Yan Zeng ◽  
Chang Yong Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Rough Surface ◽  
Design Code ◽  
Ordinary Concrete ◽  
Axial Compressive Strength ◽  
Different Characteristics

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.

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