Download or read book The Effect of Filler Shape on the Static and Dynamic Mechanical Properties of Experimental Dental Composites written by Victoria Anne Demarest and published by . This book was released on 1988 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Filler Particle Shape and Filler Loading on Flexural Properties of Experimental Dental Composite written by Steven Dewayne Florer and published by . This book was released on 2001 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1988 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Lightweight Materials and Structures written by A. Praveen Kumar and published by Springer Nature. This book was released on 2020-10-13 with total page 827 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents select proceedings of the International Conference on Advanced Lightweight Materials and Structures (ICALMS) 2020, and discusses the triad of processing, structure, and various properties of lightweight materials. It provides a well-balanced insight into materials science and mechanics of both synthetic and natural composites. The book includes topics such as nano composites for lightweight structures, impact and failure of structures, biomechanics and biomedical engineering, nanotechnology and micro-engineering, tool design and manufacture for producing lightweight components, joining techniques for lightweight structures for similar and dissimilar materials, design for manufacturing, reliability and safety, robotics, automation and control, fatigue and fracture mechanics, and friction stir welding in lightweight sandwich structures. The book also discusses latest research in composite materials and their applications in the field of aerospace, construction, wind energy, automotive, electronics and so on. Given the range of topics covered, this book can be a useful resource for beginners, researchers and professionals interested in the wide ranging applications of lightweight structures.

Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Fabrication Morphology and Dynamic Mechanical Properties of a Model Composite System Containing In situ Grown Filler written by J. L. Kardos and published by . This book was released on 1969 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The technique of in-situ crystallization was utilized to fabricate a model composite system in which the filler morphology is variable under constant interface conditions. A butadiene-acrylonitrile copolymer was chosen as the matrix from which acetanilide was crystallized in two distinctly different crystal morphologies for filler volume loadings up to 0.35. For samples crystallized at 25 and 40C, an interlocked filler phase begins to form at a filler volume fraction which depends on the crystallization temperature. The shape of the reduced modulus-filler loading curve is extremely sensitive to interlocking. In the low volume loading region (

Download or read book Physical Properties of Experimental Composite Formulations with Varying Resin Matrix and Filler Fraction written by Diana Leyva del Rio and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The K-M reflectance theory model has been used to calculate the optical properties of dental materials such as maxillofacial materials, dental ceramics and dental composites. The use of dental composites allows for minimally invasive or no preparation of the cavity when replacing missing dental hard tissues. It is also largely applied in deeper cavities, especially in the posterior segment, where the restoration needs to withstand continuous masticatory forces while maintaining its integrity. The application of conventional resin composites is technique sensitive. Placement in increments of 2 mm is the standard of care in deep cavities where it is desired the complete polymerization throughout the layers. Improper polymerization of the resin composite can lead to premature failure of the restoration due to decreased mechanical properties or could affect oral tissue by elution of monomers from the material. The depth of cure could be referred as the thickness in which the resin composite is adequately cured. The most common method used to determine the depth of cure is the one defined by the ISO 4049 standard, which involves manually scraping the uncured soft material located at the base of the specimen and then dividing the remaining depth by two. However, the evaluation of the depth of cure using surface microhardness is a simpler method that involves in applying a small load using an indenter to obtain the hardness at regular intervals throughout a linear depth of the sample and then obtain the microhardness at an arbitrary 80% from the top value. More information is necessary to have a better understanding on specific factors that can affect the microhardness and the resulting depth of cure of dental resin composites such as the influence of common base monomers in combination with incremental filler fraction.

Download or read book The Effect of Filler on the Mechanical Properties of a Novel Resin based Calcium Phosphate Cement written by Laila Al Dehailan and published by . This book was released on 2010 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several studies have found that resin-based amorphous calcium phosphate (ACP) composites can function well for applications that do not require high mechanical demand. Milled tricalcium phosphate (TCP), a new calcium-phosphate-releasing material, is crystalline in nature, suggesting it to be strong. In the present study, we investigated the use of a TCP-filled composite resin as a possible tooth restorative-material. An experimental TCP-based composite was prepared using monomer with a mixture of 34.3 percent by mass of EBPADMA, 34.2 percent by mass of HmDMA, and 30.5 percent by mass of HEMA. TCP fillers were added to the monomer mixture at different levels (30 percent, 40 percent, 50 percent, and 60 percent by weight). A universal testing machine (Sintech Renew 1121; Instron Engineering Corp., Canton, MA) was used to measure the compressive strength and modulus. FTIR was used to measure the degree of conversion. The depth of cure was determined according to the ISO standards for dental resin 4049 using the scrapping technique. Knoop hardness numbers were obtained by a microhardness tester (M-400; Leco Co., St. Joseph, MI). The viscosities of the experimental resin were determined in a viscometer (DV-II+ Viscometer; Brookfield, Middleboro, MA). The data were analyzed using a one-way analysis of variance (ANOVA). A 5-percent significance level was used for all the tests. Resin composites with 30-percent TCP filler showed the highest compressive strength and hardness values. Also, this group showed the lowest degree of conversion. Resin composites with 60-percent TCP filler showed the highest degree of conversion. However, this group showed the lowest compressive strength, depth of cure, and hardness. Resin composites with 50-percent filler showed the highest compressive modulus. Resin composites with 40-percent filler showed higher viscosity values than resin composites with 30-percent filler. In conclusion, increasing the filler level significantly reduced the compressive strength, hardness, and depth of cure, but increased the degree of conversion. Also, resin composites with the lowest filler level (30 percent) had the highest compressive strength, depth of cure, and hardness. From these results, it can be concluded that the experimental TCP-filled resin used in this study cannot be used as restorative material.

Download or read book Effect of Filler Level on the Properties of Two Experimental Composite Resin Series written by Henry Albert St. Germain (Jr.) and published by . This book was released on 1983 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Ceramic and Polymeric Composites for Various Uses written by John Cuppoletti and published by BoD – Books on Demand. This book was released on 2011-07-20 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composite materials, often shortened to composites, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or microscopic scale within the finished structure. The aim of this book is to provide comprehensive reference and text on composite materials and structures. This book will cover aspects of design, production, manufacturing, exploitation and maintenance of composite materials. The scope of the book covers scientific, technological and practical concepts concerning research, development and realization of composites.

Download or read book Dynamic Mechanical Properties of Particulate Filled Composites written by T. B. Lewis and published by . This book was released on 1969 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: The relative shear moduli of composites containing glass spheres in a rubbery matrix obey the Mooney equation, analogous to the relative viscosity of similar suspensions in Newtonian liquids. However, when the matrix is a rigid epoxy, the relative shear moduli are less than what the Mooney equation predicts but greater than what the Kerner equation predicts. Relative moduli are less for rigid matrices than for rubbery matrices because: (1) The modulus of the filler is not extremely great compared to that of the rigid matrix. (2) Poisson's ratio is less than 0.5 for a rigid matrix. (3) Thermal stresses in the matrix surrounding the particles reduce the apparent modulus of the polymer matrix because of the nonlinear stress-strain behavior of the matrix. This latter effect gives rise to a temperature dependence of the relative modulus below the glass transition temperature of the polymer matrix. Formation of strong aggregates increases the shear modulus the same as viscosity is increased by aggregation. Torsion of fluxure tests on specimens made by casting or by molding give incorrect low values of moduli because of a surface layer containing an excess of matrix material; this gives rise to a fictitious increase in apparent modulus as particle size decreases. The mechanical damping can be markedly changed by surface treatment of the filler particles without noticeable changes in the modulus. The Kerner equation, which is a lower bound to the shear modulus, is modified and brought into closer agreement with the experimental data by taking into account the maximum packing fraction of the filler particles. (Author).

Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1995 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bioactive Glass Filled Resin Composites written by Dmytro Khvostenko and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dental resin composites are widely used in modern dentistry due to their aesthetic appearance. However, resin based restorations have inferior mechanical properties (fracture is the second reason for restorations replacement) in comparison to alloy based composites and their antimicrobial properties still remain poor, leading to secondary tooth decay development on tooth-filling interface (which is the primary reason for restorations failure). In this work the Bioactive glass (BAG) was used as an antimicrobial filler. Experimental composites were prepared with 0-15 wt% BAG filler and 72-57 wt% silane treated silica glass, keeping a total filler content constant at 72 wt%. BAG composite's mechanical properties were examined, using 3-point bending beams for flexural strength measurement, pre-cracked compact-tension samples, C(T), for fracture toughness and fatigue crack growth evaluation. All mechanical properties were tested for different soaking treatments of the samples: 24 hours in DI water (all experiments) 2 months in sterile media (flexural test only) and 2 months in media with Streptococcus mutans bacteria (all experiemtns). All mechanical properties findings were compared to those ones of commercial Heliomolar composite. Main toughening mechanisms for BAG composites were evaluated post-test by SEM. The results showed that all mechanical properties for BAG composites were unaffected by increasing the filler content from 0 to 15 wt%. Moreover, all mechanical properties of BAG composites were significantly superior over Heliomolar composites. BAG composite's flexural strength properties were not affected by any of aging treatments and a slight decrease in fracture toughness and fatigue crack growth resistance was observed after 2 months soaking in media with bacteria. Main toughening mechanisms were related to BAG composite's increased filler, which resulted in more frequent crack deflection, and crack bridging at the crack tip and far away from it. In next phase of the research, a novel bioreactor and new test specimen type were developed, which allowed investigating the synergistic effect of cyclic loading and bacterial exposure on secondary tooth decay. The bioreactor was able to provide environment suitable for bacteria, similar to lab incubators. Teeth samples were machined into the disk shape (3 mm tall, 9 mm diameter), mainly consisting of dentin and the middle of sample was drilled and restored with 0 wt% BAG (0BAG) composite (2 mm deep, 5 mm diameter), introducing semi-circumferential gap between dentin and restoration of 10-30 microns. All samples were initially disinfected with 1% chloramine solution. Streptococcus mutans biofilm was grown over the samples and then they were placed in bioreactors and subjected to 1.5 Hz loading cycling at maximum load of 25% from breaking load and R=0.1 for 2 hours, followed by 4 hours resting at minimal load. The procedure was repeated for total of 2 weeks of an experiment, during which bacteria biofilm was constantly supplied with BHI media, carbon dioxide and 37oC temperature. After 2 weeks test, samples' biofilm viability was evaluated with live/dead staining kit and then, after fixing the biofilm on the samples in 4% gluteraldehyde, all samples were sectioned across the gap and stained with Gram Crysrtal Violet CAT+ dye, followed by fluorescence microscopy to reveal the depth of bacterial penetration down the gap. The depth of bacterial penetration of loaded samples was compared to one of non-loaded samples and results revealed a significantly deeper bacterial penetration for cyclically loaded samples versus non-loaded, thus, it was concluded that cyclic loading and bacterial exposure together aid secondary tooth decay propagation. In the last phase of this project the anti-microbial properties of BAG composites were evaluated. Using the same sample preparation technique and methods from the previous phase (except that now the composite was 15 wt% BAG, a.k.a 15BAG), we found out that bacterial penetration down the gap for 15BAG composite was significantly lower (almost 50% difference) in comparison to 0BAG composite, which made us confident to draw a conclusion that 15BAG composite possesses good antimicrobial properties and can be used for secondary tooth decay prevention.

Download or read book Effect of Different Percentages of Silica Nanofibers Filler Loads on Mechanical and Physical Properties of Flowable Composite Resins written by Shashikant Singhal and published by . This book was released on 2011 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dental composites are important in the spectra of restorative materials. Ability to match the color of natural dentition is an appealing characteristic of composite restorations. Additionally, they can be bonded physically to the tooth, which limits the amount of tooth preparation required and thereby conserves healthy tooth structure. In relation to other restorations like amalgams, non-metallic compositions of dental composites have exhibited good biocompatibility. The dental composites are composed of a resin matrix containing a blend of bis-GMA (bis-phenol A-glycidyldimethacrylate) or urethane dimethacrylate (UDMA) along with TEGDMA (tetraethylglycidylmethacrylate). Novel techniques for the reinforcement of these resin-based composites continue in a research and development phase, since the existing resin-filler systems may not be suitable for long term applications in large restorations. The nanofillers reinforced composite resins had shown promising results. Silica-based nanoparticles and clusters are blended with larger-sized fillers and are available commercially for restoring large posterior restorations. These nanoparticles, offer poor crack blunting ability due to their shape and very small diameters and also improves the stiffness of the composites. However, addition of fibers, by virtue of their geometry and very large aspect ratios, may provide better resistance to fracture. The objective of this study was to study the effect of silica nanofiber (SNF) and a mixture of Silica filler particles (SFP) reinforcement on the fracture toughness, flexural strength, three body wear, polymerization shrinkage, rheology, gloss and degree of conversion of bis-GMA/TEGMA based composite resin. Silica nanofibers (SNF) were fabricated using electrospinning and incorporated 20wt %, 35.8wt% and mixture of 20 wt% of SNF and SFP in ratio of 1:1 (20wt% H), into a bis-GMA/TEGDMA matrix. Experimental groups composed of clear resin and traditionally filled flowable resin (PermaFlo, Ultradent) were tested as negative and positive controls respectively. Data were analyzed using one way ANOVA and Tukey's test. Experimental group with 20 wt% of SNF and SNP mixture showed highest fracture toughness, flexural strength, wear resistant, degree of conversion. 20wt% showed highest gloss and 35.8wt% showed best rheological properties. Significant increase in all tested properties (p

Download or read book Hydrolytic Degradation of Dental Composites and Effects of Silane treatment and Filler Fraction on Compressive Strength and Thermal Expansion of Composites written by Karl-Johan M. Söderholm and published by . This book was released on 1984 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Finite Element Modeling of Dental Composite Polymerization Behavior written by Gayle A. Laughlin and published by . This book was released on 2003 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Size Effect of Clay Filler Particles on Mechanical Properties of Pultruded Polymer Composites Under Shear Loading written by Jaysimha Reddy Sonti Reddy and published by . This book was released on 2017 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer composites are finding a range of applications across different fields of engineering. Hence, there is a need to understand the properties of these polymer composites. Mechanical testing can be done to determine the properties but firstly the composite must be manufactured consuming time and money. However, if the properties gained differ from those expected from composite the obtained data is rejected, and a new composite must be manufactured consuming more time and effort. The micromechanical models play an important role in estimating the properties of the polymer composites. These models estimate the properties of the composite by estimating the properties of the constituents that build up the composite. However, these models fail to explain the effect of particle size on to the mechanical properties of the overall composites. The study reviews different micromechanical theories and focuses on the development of an analytical model that can accurately predict the effect of clay particle size on to the mechanical properties of pultruded polymer composites with clay filler particles and the numerical results are compared to experimental data to validate the analytical model.