scholarly journals Laboratory studies of heated Bulk Fill composite in the tooth cavity during filling of teeth with carious defects

2021 ◽  
Vol 19 (4) ◽  
pp. 293-298
Author(s):  
V. A. Kriventseva ◽  
Y. B. Vorobieva ◽  
V. V. Nikitenko

Aim. To study with the help of a microscope the marginal fit of Bulk-Fill group composite materials to the hard tissues of the tooth. Optimize the method of heating the composite in the cavity.Materials and methods. The marginal fit of the composite material of the Bulk-Fill group, sealed in 30 teeth of chewing anatomical and functional accessories extracted according to various indications, was studied. Materials used in the laboratory experiment: 3M ESPE Filtek posterior restorative Bulk Fill, SDR (Dentsply Sirona), Sonic Fill (Kerr). According to the manufacturers, the materials are used with the method of single-portion sealing. The research was conducted at the Department of General Dentistry of the S.M.Kirov Military Medical Academy of the Ministry of Defense of the Russian Federation.Results. 30 teeth extracted according to various indications of chewing anatomical and functional accessories were indicators were shown by the Sonic Fill (Kerr) system, due to heating and changing the viscosity of the material.Conclusions. It was proved in the laboratory that the heated composites of the Bulk-Fill group had the best edge fit during sealing than composites at normal room temperature. A nozzle was developed for heating the composite in the tooth cavity (priority application No. 2021120658 dated 12.07.2021). 

2016 ◽  
Vol 254 ◽  
pp. 207-211 ◽  
Author(s):  
Erika Popa ◽  
Liviu Pascu ◽  
Ana Socalici ◽  
Marius Ardelean

The paper relates laboratory experiments in order to obtain a composite material used for brake shoe manufacture. Regarding the testing materials were processed 38 samples. The percentage and composition of materials are: 15-45% novolac, 1,5-10% hexametyltetramin, 0-8% sulfur, 0-15% carbon fiber, 0-20% graphite, 0-25% aluminum, 15-28% brass and 0-40% rubber. The evolution of tribological and temperature parameters were analyzed in the contact zone tribological testing disk - split pin method. The composite material has the role to replace the classic material (cast iron) used in brake shoes composition in order to reduce the noise caused by rolling stock.


2014 ◽  
Vol 540 ◽  
pp. 52-55
Author(s):  
Tie Huan Sun

In many sports, tennis occupies an important position. For a tennis player, it is an important factor in a good pair of tennis to win the game. The composite materials in the production process in tennis racket are studies in this paper. Analyzed and demonstrated several ways from its function and structure, process performance, process and process analysis. Finally, the production process of the racket will be detailed study, and then a conclusion will be get that is composite material has important practical value in the production of a tennis racket.


Author(s):  
R. N. Lemeshkin ◽  
V. D. Bigunets ◽  
V. S. Belousov ◽  
A. V. Sinkiewicz

Relevance. The available unique experience of elimination of medical and sanitary consequences of emergency situations of natural, technogenic and social nature proves that the effectiveness of rendering medical care within or on the border of emergency area depends on timely arrival and actions of non-staff healthcare professionals of the All-Russian service for disaster medicine – crews for specialized medical care, physician-and-nurse crews. Directly during training and practical activities non-staff healthcare professionals face problematic issues affecting their readiness and quick response.Intention. To define the most significant problematic issues influencing work of non-staff healthcare professionals of the Service for disaster medicine of the Ministry of Defense of the Russian Federation on elimination of medical and sanitary consequences of emergency situations.Methodology. Content analysis of the facts and trends in the documents regulating activities of non-staff healthcare professionals of emergency formations was performed. Non-staff physicians were surveyed on problematic issues of training, practical activities and professional competence and importance of these issues ranked: “not important” – 1, “important” – 2, “very important” – 3 with assigning respective points.Results and Discussion. In the military-medical organizations of the central subordination, including the Kirov Military Medical Academy, emergency formations of Service for disaster medicine of the Ministry of Defense of the Russian Federation exist to strengthen (special-purpose) medical groups and medical institutions responsible for admitting casualties from emergency areas. An “average portrait” of a non-staff healthcare professional was as follows: male surgeon of 38.7±1.1 after a clinical internship, with an academic degree and experience in subject domain of 13.4 years. He has served (worked) at the Kirov Military Medical Academy and carried out functional duties on a constant basis, with experience more than two years as a part of physician-nurse or specialized medical care (thoracoabdominal) crew, with sufficient experience in elimination of medical and sanitary consequences of emergencies. At the same time during training and practical activities he faces a number of issues, such as labor relations and quality assessment of performance during elimination of medical and sanitary consequences of emergency situations, unsatisfactory resource and organizational support and also low readiness of all the non-staff members of the crew.Conclusion. Besides problematic issues of labor relations in emergency formations, the factors influencing training, performance and professional competence of non-staff healthcare professionals were defined, i.e. special equipment for medical evacuation (sanitary aviation); unsatisfactory facilities intended for elimination of medical and sanitary consequences of emergencies; medical equipment in emergency areas. As a result of the analysis, all the problematic issues were limited to 3 fundamental internal (hidden) factors influencing training, performance and professional competence of healthcare professionals at the Kirov Military Medical Academy: “Basic resources” (22.05%), “Shortcomings in daily activities” (11.9%), “Readiness for actions” (10.4%). To minimize the specified problematic issues, various (alternative) options are suggested. 


Author(s):  
Alexander L. Brown ◽  
Amanda B. Dodd ◽  
Brent M. Pickett

Composite materials are increasingly being used in aviation applications. As the quantity of composite material increases, there is a corresponding need to develop a better understanding of composite material response in fire environments. We have recently developed a program to examine this problem experimentally and computationally. Although Sandia National Laboratories and Air Force Research Laboratories at Tyndall have slightly different focuses, we are collaborating to focus on understanding duration, intensity, and the underlying physics during composite fires, as well as the technology and procedures to safely manage composite fire events. In the past year, we have been performing both small and intermediate scale testing to understand the behavior of composite materials used in aviation applications. The current focus is on a set of intermediate scale tests to generate data useful for understanding the behavior of carbon fiber epoxy composites in adverse thermal environments. A series of tests has been performed in a 90 cm cubic enclosure with 25–40 kg of composite materials to generate a severe fire environment fueled mostly by the composites. Preliminary results of these tests will be reported to provide data on the severity of the environment in terms of thermal intensity, duration, and chemical products.


2014 ◽  
Vol 783-786 ◽  
pp. 2485-2490 ◽  
Author(s):  
Noboru Nakayama ◽  
M. Horita ◽  
H. Miki ◽  
T. Takagi ◽  
H. Takeishi

The materials used for fuel cell separators require a bending strength of more than 70 MPa. Therefore, the contact resistance is required to be 10 mΩ∙cm2, respectively. In the present study, vapor grown carbon nanofibers (VGCF) were added to Ti composite using the compression shearing method at room temperature. The mechanical properties of the compacted powder were then measured. The microstructure of the Ti/VGCF composite material was Ti with dispersed VGCF (not alloyed). In addition, the bending strength of all Ti/VGCF composites was more than 800 MPa, and the bending strength of 0-1 vol% VGCF composites was twice as much as that for Ti rolled material (ASTM grade 2). Ti/VGCF thin plates also exhibited excellent electrical property. The contact resistance of 5 vol% VGCF was found to be three times smaller than that of Ti rolled material. These properties make the Ti/VGCF composite material suitable as a separator material.


2020 ◽  
pp. 25-28
Author(s):  
L. V. Iyashvili ◽  
Yu. A. Vinnichenko ◽  
O. G. Avraamova

The purpose of the study was a clinical electrometric assessment of the quality of the marginal fit of the composite material to the hard tissues of the tooth, depending on the type and amount of adhesive used the influence of the adhesive, namely: the mechanism of its action and quantity, on the quality of restoration of the hard tissues of the tooth lost by the carious process in the composite material over time.Material and methods. In clinical conditions, 140 fillings were examined, the placement of which was carried out only in cavities of classes 1 and 2, with the area affected by the carious process of hard tooth tissues from 30 to 50 mm2. For this, composite material ESTET X and adhesive systems were used: one-component XP BOND and self-etching XENO V in different volumes (6.6 and 17.7 mg). To assess the marginal fit of the filling material to the hard tissues of the tooth, the multifunctional electro-diagnostic device EST-DENT (Geosoft, Russia) was used. The principle of operation of the device is based on measuring the strength of the current flowing through the hard tissues of the tooth under the influence of a low-voltage source of electrical power. Results. The quality of the marginal fit of composite fillings to the hard tissues of the tooth, which is the main factor determining the durability of their functioning, largely depends on the amount of adhesive used, its mechanism of action, the area and depth of the carious lesion of dentin. Over time, there is a change in the structure obtained as a result of the mechanical and chemical interaction of the adhesive system and hard tissues of the tooth (primarily the hybrid layer), in the direction of decreasing its density and breaking integrity. This in turn increases the amount of electric current passing through it.Conclusions. An analysis of the obtained clinical data shows that when restoring hard tissues of teeth lost over large areas and located close to the pulp cavity of the coronal part of the tooth, it is necessary to take into account the effect of dentinal fluid on the quality and durability of the restoration. The use in these cases of adhesive systems in an amount of not less than 17.7 mg (a drop from dispenser), careful preparation of the affected tooth tissues, rational design of the formed cavity, strict adherence to the manufacturer’s recommendations on the time of use of the adhesive. can significantly reduce the risk of unsatisfactory treatment results.


2005 ◽  
pp. 123-134
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Branislav Bajceta ◽  
Predrag Stajcic ◽  
Srdjan Bosnjak

The aim of this paper was to present the determination of tensile strength Rm and modulus of elasticity Et of glass-epoxy composites at two different temperatures (at room temperature t=20?C, and at t =?50?C). Standard mechanical testing was carried out on glass woven-epoxy composite material with different structures (two specific weights of reinforcement, 210 g/m2 and 550 g/m2) and orientations (0?/90? and ?45?). Micromechanical analysis of failure was performed on a stereo microscope and SEM in order to determine real models and mechanisms of crack.


Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1607
Author(s):  
Renata Ildikó Szavá ◽  
Ioan Szavá ◽  
Sorin Vlase ◽  
Arina Modrea

The properties of a composite material are determined by the properties of the constitutive materials. In engineering practice, there are many situations in which we have composite material, but we do not have information about the properties of each phase component. The measurements we can make in such cases are on the existing material, thus being able to determine, experimentally, the global physical properties of the composite. The possibility of realizing an estimate of the mechanical properties of each component poses a problem if we start from these measurements. The paper proposes a method to achieve this, starting from the theoretical estimates established in the literature, then illustrated by an example to determine the properties of wood. Wood is a transverse isotropic material and therefore the constitutive law has symmetries that are manifested in the decrease of the number of parameters that define the stress-strain liason, defined only by five independent parameters. The proposed method can be extended to a diversity of models and materials used in the study of composite materials.


2021 ◽  
Vol 31 (2) ◽  
pp. 101-108
Author(s):  
Faiza Khalid ◽  
Manaa Rabah ◽  
Saad Salah ◽  
Ameddah Hacene

The turbine blades are subjected to high operating temperatures and high centrifugal tensile stress due to rotational speeds. The maximum temperature at the inlet of the turbine is currently limited by the resistance of the materials used for the blades. The present paper is focused on the thermo-mechanical behavior of the blade in composite materials with reinforced mast under two different types of loading. The material studied in this work is a composite material, the selected matrix is a technical ceramic which is alumina (aluminum oxide Al2O3) and the reinforcement is carried out by short fibers of high modulus carbon to optimize a percentage of 40% carbon and 60% of ceramics. The simulation was performed numerically by Ansys (Workbench 16.0) software. The comparative analysis was conducted to determine displacements, strains and Von Mises stress of composite material and then compared to other materials such as Titanium Alloy, Stainless Steel Alloy, and Aluminum 2024 Alloy. The results were compared in order to select the material with the best performance in terms of rigidity under thermo-mechanical stresses. While comparing these materials, it is found that composite material is better suited for high temperature applications. On evaluating the graphs drawn for, strains and displacements, the blade in composite materials reinforced with mast is considered as optimum.


Author(s):  
N. Pavan ◽  
Jaysaheel I. Harti ◽  
K. S. Harishanand

There are various types of engineering materials used in both commercial as well as non-commercial applications, it becomes important to think about the life of the material, to prove about the economical aspect of the material. In order to increase the life, the conventional engineering materials fails in one or the other aspects. So the arrival of composite materials is important, which shows better mechanical properties than the regular engineering materials with lower weights. A study on the wear behaviour of a composite material (Al-B4C), under varying concentration of the reinforcement is made to understand the material usability under the cyclic operating conditions.


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