The effect of TiO2 nanotubes reinforcement on the mechanical properties and wear resistance of silica micro-filled dental composites

2018 ◽  
Vol 53 (23) ◽  
pp. 3217-3228 ◽  
Author(s):  
Abolfazl Mirjalili ◽  
Ali Zamanian ◽  
Seyed Mohammad Mahdi Hadavi
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Flexural Strength ◽  
Water Sorption ◽  
Hydrothermal Process ◽  
Physical And Mechanical Properties ◽  
Dental Composite ◽  
Dental Composites ◽  
Dental Resin ◽  
Electron Microscopies

One of the most important aspects of dental resin composites is the ability to improve mechanical properties by adding reinforcing filler particles. TiO2 nanotubes are expected to improve the physical and mechanical properties of silica micro-filled dental composite. Therefore, TiO2 nanotubes were synthesized using an alkaline hydrothermal process and then functionalized with 3-methacryloxypropyl-trimethoxysilane. TiO2 nanotubes were characterized by scanning and transmission electron microscopies, X-ray diffraction and Fourier transform infrared spectroscopy. Different quantities of TiO2 nanotubes and silica microparticles were reinforced in bisphenol A-glycidyl methacrylate (Bis-GMA) and tri-ethylene glycol dimethacrylate to prepare dental composite samples. Thereafter, the flexural strength and modulus, compressive strength, degree of conversion of monomers, wear resistance and water sorption were utlized to examine the prepared composites. The flexural strength and wear resistance of composites with 3 wt% TiO2 nanotubes significantly increased in comparison with other composites. On the other hand, due to the stability of composite, the water sorption was decreased. Therefore, TiO2 nanotubes reinforcement could be a promising solution for the improvement of mechanical properties in dental composites.

Mechanical Properties of Machinable Zirconia Dental Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1587-1589
Author(s):  
Wen Xu Li ◽  
Hua Zhao ◽  
Ying Song ◽  
Bin Su ◽  
Fu Ping Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Calcium Phosphate ◽  
Flexural Strength ◽  
Dental Composite ◽  
The Other ◽  
Dental Composites ◽  
Composite Ceramics ◽  
Cad Cam ◽  
The Common

Ca3(PO4)2/ZrO2 dental composite ceramics using for CAD/CAM system were prepared and the effects of weak phases on microstructures and mechanical properties were studied. The results showed that intergranular spreads happened with the increasing Ca3(PO4)2 contents due to the discontinuity of weak interfaces between Zirconia and Calcium phosphate in matrix. So the flexural strength and hardness of the Ca3(PO4)2/ZrO2 composite ceramics were decreased effectively, which improved the machinability of the composites. On the other hand, strong interfaces between Zirconias increased the integrality of the ceramic structures. ZrO2 composite Ceramics with 15% Ca3(PO4)2 were sintered at 1350°C. The flexural strength is 300.44MPa, fracture toughness is 4.36 MPam1/2, and hardness is 6.69 GPa. The cutting exponent of the Ca3(PO4)2/ZrO2 composite ceramics is obviously lower than that of the common commercial Vita Mark II and Dicor MGC ceramics, which shows good mechanical properties and machinability.

The Improvement of Dental Composite Properties with Electromagnetically Aligned Nanofiber

2014 ◽  
Vol 1685 ◽  
Author(s):  
Tansel Uyar ◽  
Dilek Cokeliler
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Composite Resins ◽  
Dental Composite ◽  
Bending Test ◽  
Dental Composites ◽  
Layer By Layer ◽  
Aligned Fibers ◽  
Electrode Systems

ABSTRACTBecause of the aesthetics, handy and low cost features, acrylic resin is the main material in denture fabrication last 40 years. The purpose of this study is to improve mechanical properties of acrylic based dental composites used in dentistry by applying nanofiber approaches. Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling but sometime this material can be fractured or cracked in clinical use because of the strength issues that is frequently used in restorative dentistry in recent years. A wide variety of fillers that are used to produce PMMA composites draw the attention in literature. Using PMMA composite resins with electrospun polyvinylalcohol (PVA) nanofiber fillers is our first novelty. Also the producing and using aligned electrospun fibers as a filler is our second novelty of this practice. PVA was selected as composite filler because of biocompatibility and preparing easily also has non-toxic solvent. Electrospinning system is manufactured that allows manipulation of electric field used in the application of alignment in lab scale. Various auxillary electrode systems are used for different patterns of alignment with the manufactured device and electrode systems produce fibers in different range of diameter. Scanning electron microscopy (SEM) is used for physical characterization and determined the range of fiber diameters. After the optimization of concentration step non-woven and aligned fibers are also analyzed. Non-woven fiber has no unique pattern because of the nature of electrospinning but aligned fibers has crossed lines. These produced fibers structured as layer-by-layer form with different features are used in producing PMMA dental composites with different volume ratios. In the last part of the research, PMMA dental composites are produced with aligned and formless fibers that are characterized with three-point bending test. The maximum flexural strength figure shows that fiber load by weight %0.25 and above improves the maximum. The change of flexural strength, elastic modulus values and toughness are obtained and compared with formless and aligned PVA nanofiber included composite specimens. As a result, mechanical properties of PMMA dental composites are improved with using PVA nanofibers as a filler also with the usage of aligned fibers instead of the formless ones the effects of improvement gets better with maximum values as 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), 170kJ/m3 (toughness).

scholarly journals Influence of artificial aging: mechanical and physicochemical properties of dental composites under static and dynamic compression

2021 ◽  
Author(s):  
D. C. Gornig ◽  
R. Maletz ◽  
P. Ottl ◽  
M. Warkentin
Keyword(s):  
Mechanical Properties ◽  
Water Sorption ◽  
Artificial Aging ◽  
Filler Content ◽  
Dynamic Compression ◽  
The Other ◽  
Chemical Degradation ◽  
Dental Composites ◽  
Compression Tests ◽  
Acid Ph

Abstract Objective The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in vitro aging. Materials and Methods Specimens (1 mm3) of three commercially available composites (GrandioSO®, Arabesk Top®, Arabesk Flow®) with respect to their filler content were stored in artificial aging media: artificial saliva, ethanol (60%), lactic acid (pH 5) and citric acid (pH 5). Parameters (Vickers microhardness, compressive strength, elastic modulus, water sorption and solubility) were determined in their initial state (control group, n = 3 for microhardness, n = 5 for the other parameters) and after 14, 30, 90 and 180 days (n = 3 for microhardness, n = 5 for the other parameters for each composite group, time point and media). Specimens were also characterized with dynamic-mechanical-thermal analysis (compression tests, F =  ± 7 N; f = 0.5 Hz, 1 Hz and 3.3 Hz; t = 0–170 °C). Results Incorporation of fillers with more than 80 w% leads to significantly better mechanical properties under static and dynamic compression tests and a better water sorption behavior, even after chemical degradation. The influence of degradation media and time is of subordinate importance for chemical degradation. Conclusion Although the investigated composites have a similar matrix, they showed different degradation behavior. Since dentine and enamel occur only in small layer thickness, a test specimen geometry with very small dimensions is recommended for direct comparison. Moreover, the use of compression tests to determine the mechanical parameters for the development of structure-compatible and functionally adapted composites makes sense as an additional standard. Clinical relevance Preferential use of highly filled composites for occlusal fillings is recommended.

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.

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 The Photoinitiators Used in Resin Based Dental Composite—A Review and Future Perspectives

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 470
Author(s):  
Andrea Kowalska ◽  
Jerzy Sokolowski ◽  
Kinga Bociong
Keyword(s):  
Current Knowledge ◽  
Biomechanical Properties ◽  
Degree Of Conversion ◽  
Dental Composite ◽  
Polymerization Process ◽  
Dental Composites ◽  
Dental Resin ◽  
Dental Resins ◽  
Light Curing

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.

scholarly journals Properties of High-Strength Flowable Mortar Reinforced with Palm Fibers

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Test Results ◽  
Palm Fiber ◽  
Toughness Index ◽  
Strength And Toughness

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.

Research on Mechanical Properties of Crumb Rubber Concrete

2011 ◽  
Vol 477 ◽  
pp. 290-295 ◽  
Author(s):  
Li Bo Bian ◽  
Shao Min Song
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Apparent Density ◽  
Crumb Rubber ◽  
Fatigue Performance ◽  
Brittleness Index ◽  
Mixing Ratio ◽  
Rubber Concrete

Considering large number production of the abandoned tyres and the question of the concrete with mixture of crumb rubber，the mainly task of this paper is to study the mechanical properties of different mixing ratio concrete with vary volume of crumb rubber. The results showed that the workability, apparent density, compressive strength, flexural strength and brittleness index decrease as the increase of crumb rubber. While the anti-crack performance and anti-fatigue performance can be improved. The wear-resistance properties are a little lower than common concrete.

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 Physical, mechanical properties and wear resistance of iron-base matrix materials for sintered diamond tools fabricated by HP and SPS

Mechanik ◽  
2018 ◽  
Vol 91 (10) ◽  
pp. 846-849
Author(s):  
Elżbieta Bączek
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Metal Matrix ◽  
Physical And Mechanical Properties ◽  
Full Density ◽  
Matrix Composites ◽  
Plasma Sintering ◽  
Base Matrix ◽  
Spark Plasma ◽  
Sintered Diamond

Metal matrix composites were prepared by hot pressing (HP) and spark plasma sintering (SPS) techniques. Ball-milled ironbase powders were consolidated to near full density by these methods at 900°C. The physical and mechanical properties of the resulting composites were investigated. The specimens were tested for resistance to both 3-body and 2-body abrasion. The composites obtained by HP method (at 900°C/35 MPa) had higher density, hardness and resistance to abrasion than those obtained by SPS method.

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