scholarly journals Evaluation of the Loading, Unloading, and Permanent Deformation of Newly Available Epoxy Resin Coated Ni-Ti Wires Using Self-Ligating Brackets

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Hazel Garro-Piña ◽  
María Cristina Jiménez-Cervantes ◽  
Ricardo Ondarza-Rovira ◽  
Roberto Justus ◽  
Salvador García-López
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Clinical Management ◽  
Permanent Deformation ◽  
Applied Force ◽  
Bending Test ◽  
Recovery Cycle ◽  
Three Point Bending ◽  
Significant Difference

Aim. The purpose of this study was to evaluate the load and unload deflection and permanent deformation of round 0.016′′ and rectangular 0.016′′×0.022′′ regular and coated Ni-Ti wires. Materials and Methods. Ni-Ti archwires produced by two manufacturers were evaluated. Both regular and coated round and rectangular Ni-Ti wire segments (n=15) from each group were submitted to a three-point bending test. Both types of wires were evaluated for permanent deformation at the end of a recovery cycle. Results. The coated round 0.016′′ Ni-Ti wires produced a significantly lower force in loading (p<0.01) and unloading (p<0.01) than regular wires of the same manufacturer and size. There was no significant difference in permanent deformation between coated and regular round Ni-Ti wires from the same company. For rectangular 0.016×0.022′′ Ni-Ti wires, there was a significant difference in the loading evaluation, but the unloading test presented no significant differences. The permanent deformation of the rectangular wires revealed no significant difference between them. Conclusion. The addition of an esthetic coating to these new Ni-Ti wires produced changes in their mechanical properties, manifested as a reduction in the applied force, which should be considered in clinical management.

scholarly journals Effect of Preheating on the Mechanical Properties of Resin Composites

2008 ◽  
Vol 02 (04) ◽  
pp. 263-268 ◽  
Author(s):  
Mine Betül Uctasli ◽  
Hacer Deniz Arisu ◽  
Lippo VJ Lasilla ◽  
Pekka K Valittu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Testing Machine ◽  
Bending Test ◽  
Resin Composites ◽  
Three Point Bending ◽  
Commercial Resin ◽  
Significant Difference ◽  
Light Curing ◽  
Post Hoc

ABSTRACTObjectives: The purpose of this study was to compare the flexural strength and modulus of two commercial resin composites, at room temperature and 40, 45 and 50�C prior to light polymerization with standard and step-cure protocols.Methods: One nanohybrid (Grandio, VOCO, Cuxhaven, Germany), and microhybrid compositeresin (Filtek Z250, 3M ESPE, St. Paul, MN, USA) were used. The materials were inserted into rectangular moulds at room temperature or preheated to a temperature of 40, 45 or 50°C and cured with standard or step-cure protocols with high intensity halogen (Elipar Highlight, 3M-ESPE, St. Paul, MN, USA). Ten specimens were prepared for each preheating and light curing protocol. A three-point bending test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed by one-way analysis of variance and Tukey’s post hoc tests (P<.05) to examine the effect of curing protocol and preheating. Pearson’s correlation test was used to determine the correlation between tested mechanical properties and preheating.Results: There were no statistically significant difference between tested mechanical properties of the materials, curing protocols and temperature of the materials. No significant correlation was found between preheating and tested mechanical properties.Conclusions: The mechanical properties of the tested materials did not changed by preheating so the tested materials could be preheated because of the other potential clinical advantages like more adaptation to the cavity walls. (Eur J Dent 2008;2:263-268)

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

Influence of Honeycomb Core Compression on the Mechanical Properties of the Sandwich Structure

2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek
Keyword(s):  
Mechanical Properties ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Low Velocity Impact ◽  
Bending Test ◽  
Honeycomb Core ◽  
Low Velocity ◽  
Three Point Bending ◽  
Core Technology

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.

Bending Properties of General Purpose Stainless Steel Wire Formed for Orthodontic Use

2013 ◽  
Vol 746 ◽  
pp. 394-399
Author(s):  
Niwat Anuwongnukroh ◽  
Yosdhorn Chuankrerkkul ◽  
Surachai Dechkunakorn ◽  
Pornkiat Churnjitapirom ◽  
Theeralaksna Suddhasthira
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Orthodontic Treatment ◽  
Steel Wire ◽  
General Purpose ◽  
Stainless Steel Wire ◽  
Bending Test ◽  
Bending Properties ◽  
Steel Wires ◽  
Significant Difference

The archwire is generally used in fixed appliances for orthodontic treatment to correct dental malocclusion. However, it is interesting to know whether general purpose stainless steel wire could replace commercial orthodontic archwire in orthodontic practice for economic reasons. The purpose of this study was to determine the bending properties of general purpose stainless steel wire compared with commercial orthodontic stainless steel wires after forming as an archwire for orthodontic use. The samples used in this study were 90 general purpose and 45 commercial (Highland) round stainless steel wires in 0.016, 0.018, and 0.020 sizes (30 general purpose and 15 commercial wires for each size). All 15 general purpose stainless steel wires with different sizes were formed into orthodontic archwire with a Universal Testing Machine. All samples were tested (three-point bending test) for mechanical properties. The results showed no significant difference between general purpose and commercial orthodontic wires in size 0.016 for 0.1 mm offset bending force, 0.2% yield strength, and springback. Although many mechanical properties of general purpose wires differed from commercial wires, their values conformed to other previous studies within the range of clinical acceptance. In conclusion, orthodontic formed general purpose round stainless steel wires had statistically different (p <0.05) mechanical properties from commercial orthodontic stainless steel wires (Highland) but the mechanical properties were acceptable to use in orthodontic treatment.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

Thermo Mechanical behaviour of Phenol Novolac Resin and Unsaturated Polyester Toughened Epoxy using nano Bentonite and Silica Nanoparticles

2020 ◽  
Vol 1 (3) ◽  
pp. 77-83
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Silica Nanoparticles ◽  
Moisture Absorption ◽  
Unsaturated Polyester ◽  
Physical And Mechanical Properties ◽  
Bending Test ◽  
Mechanical And Thermal Properties ◽  
Novolac Epoxy ◽  
Industrial Needs

Phenol novolac epoxy resin is a polymer matter which its properties can be modified for industrial needs. In this research, nanocomposites of phenol novolac epoxy resin and unsaturated polyester are made nano Bentonite and silica nanoparticles as filler. For this purpose, effect of nanoparticles percent on nanocomposite formation is studied and their physical, mechanical and thermal properties are obtained. The presence of unsaturated polyester in this process forms a cross-link capable of improving the physical and mechanical properties of epoxy resin. Fracture behavior was determined by a SEM device. Moreover, TGA, DSC, impact tests and bending test were applied for data analysis. When process ability is growing, moisture absorption decreases. Fracture toughness was also evaluated in a stoichiometric network. Physical and mechanical properties improve significantly with increasing nanoparticles. The most important reason for using this nanocomposite is its high resistance to corrosion.

scholarly journals Effect of Gamma Radiation and Endodontic Treatment on Mechanical Properties of Human and Bovine Root Dentin

2016 ◽  
Vol 27 (6) ◽  
pp. 670-674 ◽  
Author(s):  
Veridiana Resende Novais ◽  
Priscilla Barbosa Ferreira Soares ◽  
Carlla Martins Guimarães ◽  
Laís Rani Sales Oliveira Schliebe ◽  
Stella Sueli Lourenço Braga ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Gamma Radiation ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Endodontic Treatment ◽  
Bending Test ◽  
Human Teeth ◽  
Significant Difference ◽  
Root Dentin

Abstract This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single-rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect.

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.

The Effect of the Compression on the Mechanical Properties of Wood Material

2007 ◽  
Vol 537-538 ◽  
pp. 41-46 ◽  
Author(s):  
László Kuzsella ◽  
Imre Szabó
Keyword(s):  
Mechanical Properties ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Bending Test ◽  
Wood Material ◽  
Ordinary Life ◽  
Three Point Bending ◽  
Wide Range ◽  
New Process ◽  
New Applications

The wood is one of the most favourable structural material. It appears on all fields of the ordinary life. It is difficult to say an application where the wood is not used due to its cheap price, availability and just simply the beauty. Beside of the wide range of process technologies a new process appeared. This process changes the properties of the material and brings many new applications to this traditional material. This process is the compression of the structural wood material. This publication deals with the effect of the compression on the mechanical properties of two hardwoods (beech: fagus sylvatica, oak: quercus) by the help of the three-point bending test and the Charpy impact test.

Sign in / Sign up

Export Citation Format

Share Document