scholarly journals Force Relaxation Characteristics of Medium Force Orthodontic Latex Elastics: A Pilot Study

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Daniel J. Fernandes ◽  
Gisele M. Abrahão ◽  
Carlos N. Elias ◽  
Alvaro M. Mendes
Keyword(s):  
Tensile Testing ◽  
Statistical Significance ◽  
Testing Machine ◽  
Force Extension ◽  
Time Period ◽  
Force Decay ◽  
Force Relaxation ◽  
Static Tensile ◽  
Decay Pattern ◽  
Relaxation Characteristics

To evaluate force extension relaxation of different brands and diameters of latex elastics subjected to static tensile testing under an apparatus designed to simulate oral environments, sample sizes of 5 elastics from American Orthodontics (AO), Tp, and Morelli Orthodontics (Mo) of equivalent medium force, (3/16, 1/4, and 5/16 inch size) were tested. The forces were read after 1-, 3-, 6-, 12- and 24-hour periods in Emic testing machine with 30 mm/min cross-head speed and load cell of 20 N. Two-way ANOVA and Bonferroni tests were used to identify statistical significance. There were statistically differences among different manufacturers at all observation intervals (P<0.0001). The relationships among loads at 24-hour time period were as follows: Morelli>AO>Tp for 3/16, 1/4, and 5/16 elastics. The force decay pattern showed a notable drop-off of forces until 3 hours, a slight increase in some groups from 3–6 hours and a more homogeneous force pattern over 6–24 hours.

scholarly journals Force extension relaxation of medium force orthodontic latex elastics

2011 ◽  
Vol 81 (5) ◽  
pp. 812-819 ◽  
Author(s):  
Daniel J. Fernandes ◽  
Gisele M. A. Fernandes ◽  
Flavia Artese ◽  
Carlos N. Elias ◽  
Alvaro M. Mendes
Keyword(s):  
Statistical Significance ◽  
Testing Machine ◽  
Force Extension ◽  
Time Period ◽  
Force Decay ◽  
Force Relaxation ◽  
Static Tensile ◽  
Decay Pattern ◽  
Force Reduction ◽  
Progressive Force

Abstract Objective: To evaluate the force extension relaxation of different manufacturers and diameters of latex elastics subjected to static tensile testing under dry and wet conditions. Materials and Methods: Sample sizes of 15 elastics from American Orthodontics (AO) (Sheboygan, Wis), TP (La Porte, Ind), and Morelli Orthodontics (Sorocaba SP, Brazil) were used. Equivalent medium force products were tested—3/16, 1/4, and 5/16 inch lumen size from each manufacturer—making a total of 1080 specimens. An apparatus was designed to simulate oral environments during elastics stretching. Forces were read after 1, 3, 6, 12, and 24 hour periods using the Emic Testing Machine (Emic Co., Sao Paulo, Brazil) with 30 mm/min cross-head speed and load cell of 20 N (Emic Co). Kruskal-Wallis and Dunn's tests were used to identify statistical significance. Results: Statistical differences between AO and the other brands were noted for all testing times. Significant variation in mechanical properties was observed in latex elastics from Morelli. Relationships among loads at the 0 hour time period were as follows: Morelli&gt;AO&gt;TP for 3/16 elastics (P  =  .0016), 1/4 elastics (P  =  .0016), and 5/16 elastics (P  =  .0087). Conclusion: Significant differences in force extension relaxation were noted for elastics from these manufacturers. Force relaxation over the 24 hour time period was AO&gt;Morelli&gt;TP for 3/16 elastics, AO&gt;TP&gt;Morelli for 1/4 elastics, and TP&gt;AO&gt;Morelli for 5/16 elastics. The force decay pattern showed a notable drop-off of forces during 0 to 3 hours, a slight increase in force values from 3 to 6 hours, and a progressive force reduction over 6 to 24 hours.

scholarly journals An in vitro comparison of the force decay generated by different commercially available elastomeric chains and NiTi closed coil springs

2007 ◽  
Vol 21 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ana Cristina Soares Santos ◽  
André Tortamano ◽  
Sandra Regina Frazatto Naccarato ◽  
Gladys Cristina Dominguez-Rodriguez ◽  
Julio Wilson Vigorito
Keyword(s):  
Artificial Saliva ◽  
Testing Machine ◽  
In Vitro Study ◽  
Original Length ◽  
Force Decay ◽  
Decay Pattern ◽  
The Mean ◽  
Initial Force ◽  
Elastomeric Chains

This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°C. Initial force was measured by means of an Instron universal testing machine and then at 1, 4, 7, 14, 21, and 28 days. The results revealed that the elastomeric chains delivered a mean initial force of 347 g for Morelli®, 351 g for American Orthodontics®, 402 g for Abzil®, and 404 g for TP Orthodontics®. The NiTi closed coil springs generated a mean initial force of 196 g for American Orthodontics®, 208 g for TP Orthodontics®, 216 g for Abzil®, and 223 g for Morelli®. The mean percentage of force decay observed after 28 days for the elastomeric chains was 37.4% for TP Orthodontics®, 48.1% for American Orthodontics®, 65.4% for Morelli®, and 71.6% for Abzil®. After 28 days, the NiTi closed coil springs presented a mean percentage of force decay of 22.6% for American Orthodontics®, 29.8% for Abzil®, 30.6% for Morelli®, and 45.8% for TP Orthodontics®. At the end of the study, significant differences were observed between the elastomeric chains and the NiTi closed coil springs. The results indicated that the studied NiTi closed coil springs are more adequate for dental movement than the elastomeric chains.

scholarly journals Comparative evaluation of force decay pattern in orthodontic active tiebacks exposed to five different mouth rinses: An in vitro Study

2020 ◽  
Vol 14 (4) ◽  
pp. 244-249
Author(s):  
Amir Hossein Mirhashemi ◽  
Atefe Saffar Shahroudi ◽  
Keyvan Shahpoorzadeh ◽  
Niloofar Habibi Khameneh
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Control Group ◽  
Mouth Rinses ◽  
Force Decay ◽  
Force Relaxation ◽  
Decay Pattern ◽  
Initial Force ◽  
And Control

Background. This study compared the force decay pattern of two different orthodontic active tiebacks (ATBs) exposed to five different commercially available mouth rinses. Methods. In this in vitro study, 90 transparent ATBs and 90 gray ATBs were divided into six groups; one was the control group, and the others were exposed to one of these mouth rinses twice a day for 60 seconds: Listerine, chlorhexidine, Orthokin, Persica, and fluoride. The initial force of each ATB was 250 g at a 24-mm extension. The force of ATBs was measured on days 1, 7, 14, and 28 using a digital gauge. Results. The highest percentage of force loss was observed between days 14 and 28 (P<0.05). At the end of the study, the Persica group exhibited the highest force degradation in both ATB types. In the transparent ATBs, it was followed by Orthokin, Listerine, fluoride, chlorhexidine, and control groups, respectively. In the gray ATBs, Orthokin, chlorhexidine, control, Listerine, and fluoride groups exhibited the highest force decay in descending order. In some groups, the differences between transparent and gray ATBs were significant. In the control group, the force of transparent ATB was significantly higher than gray ones on days 7 and 14 but not significantly after four weeks. Conclusion. ATBs’ force degradation could be exacerbated by the use of some mouth rinses. There were some differences between force relaxation patterns of transparent and gray ATBs. The data could be beneficial in choosing appropriate O-rings for making ATBs.

Tensile Testing of Hybrid Composite Joints

2014 ◽  
Vol 575 ◽  
pp. 452-456 ◽  
Author(s):  
Giuseppe Lamanna ◽  
Raffaele Sepe ◽  
A. Pozzi
Keyword(s):  
Tensile Testing ◽  
Failure Process ◽  
Testing Machine ◽  
Experimental Tests ◽  
Lap Joints ◽  
Stacking Sequence ◽  
Single Lap Joints ◽  
Universal Testing ◽  
Static Tensile ◽  
Carbon Fiber Epoxy

In the present paper, results of experimental tests carried out on hybrid (bonded/bolted) and adhesive composite single-lap joints are showed. The laminate adherends were made by unidirectional carbon fiber/epoxy with symmetric stacking sequence. In particular, the tests were carried out to evaluate strength and failure mode of the different joints. These joints were subjected to quasi-static tensile displacement and tests were conducted using a universal testing machine. The maximum tension load that the specimen can bear is determined and the failure process is correlated to the lay-up of the composite and joint type.

Effect of Boron on Microstructure and Mechanical Property of High Grade Pipeline Steel

2011 ◽  
Vol 299-300 ◽  
pp. 319-322
Author(s):  
Xing Chang Tang ◽  
Yong Lin Kang ◽  
Yan Yan Bo ◽  
Lei Fan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Tensile Testing ◽  
Pipeline Steel ◽  
Testing Machine ◽  
High Grade ◽  
Tensile Testing Machine ◽  
Static Tensile ◽  
Microstructure And Mechanical Property ◽  
Electronic Microscope

The correlation among boron, microstructure and mechanical property of the X120 pipeline steel was investigated in this study. The mechanical properties of the steels were tested with quasi-static tensile testing machine. The microstructure of the steels with different boron contents was observed with scanning electronic microscope (SEM) and transmission electronic microscope (TEM). The result shows that by adding a small amount of boron the mechanical property of pipeline steel can be improved effectively.

scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

Use of a Durometer to Assess Onion Bulb Hardness

1978 ◽  
Vol 14 (3) ◽  
pp. 269-272 ◽  
Author(s):  
J. F. M. Fennell
Keyword(s):  
Tensile Testing ◽  
Test Procedure ◽  
Testing Machine ◽  
Onion Bulb ◽  
Tensile Testing Machine ◽  
Varietal Differences ◽  
Onion Bulbs ◽  
Non Destructive

SUMMARYThe use of a durometer to assess hardness of onion bulbs is described, and compared with the use of a tensile testing machine. Results from the two tests were closely correlated, and significant varietal differences were detected in bulb hardness by both machines. The durometer is of particular value because of the simplicity and non-destructive nature of the test procedure.

Design and Mechanical Evaluation of Sutureless Implants for the Surgery Treatment of Rotator Cuff Tears

2021 ◽  
Author(s):  
Marcília Valéria Guimarães ◽  
Elton Bonifácio ◽  
Thiago Carmo ◽  
Cleudmar Araújo
Keyword(s):  
Rotator Cuff ◽  
Mechanical Behavior ◽  
Functional Disability ◽  
Statistical Significance ◽  
Testing Machine ◽  
Rotator Cuff Tears ◽  
Suture Anchors ◽  
Pullout Strength ◽  
Rigid Foam ◽  
Pullout Tests

Abstract Rotator cuff (RC) tears cause pain and functional disability of the shoulder. Despite advances in suture anchors, there are still reports about the incidence of surgical-related injuries to RC mainly associated with sutures. The purpose of this study was to design and evaluate the mechanical behavior of sutureless implants to repair RC tears. We hypothesized that the implants present mechanical characteristics suitable for the surgical treatment of RC tears as suture anchors. Three different implants (T1,T2,T3) were designed and fabricated with titanium: T1 has two rods and rectangular head; T2 has two rods with a small opening and enlarged rectangular head and T3 has three rods and a circular head. The implants were fixed in rigid polyurethane foam blocks by a series of blows, and the applied mechanical loads along with the number of blows were quantified. Pullout tests using tapes fixed between the implant head and testing machine grip were conducted until implant failure. The maximum pullout strength and displacement of the implant relative to the rigid foam block were computed. Statistical significance was set at p &lt; 0.05. Owing to its geometric configuration, implant T2 presented the best characteristics related to stability, strength, and ease of insertion. Implant T2 confirms our hypothesis that its mechanical behavior is compatible with that of suture anchors which could lead to the reduction of RC repair failures and simplify the arthroscopic procedure.

Research of the Mechanical Properties of the Filament from the Percentage of Filling when Prototyping Machine Parts

2021 ◽  
Vol 410 ◽  
pp. 617-623
Author(s):  
Elena N. Gryadynova ◽  
Andrey V. Gorin ◽  
Alexey Yu. Rodichev
Keyword(s):  
Tensile Strength ◽  
Tensile Testing ◽  
Testing Machine ◽  
Experimental Studies ◽  
Relative Deformation ◽  
Strain Diagram ◽  
Experimental Sample ◽  
Tensile Testing Machine ◽  
Machine Parts ◽  
Fisher’S Criterion

The article contains the analysis of thermoplastics used in prototyping machine parts. We used several types of experimental samples with different filling percentages. The equipment on which the experimental studies were carried out is shown. During the experiment, a specialized tensile testing machine was used. The experimental samples were installed in the developed centering device. Normal conditions were observed during the tests. The results of an experimental tensile study of PLA-plastic specimens are presented. The typical stress-strain diagram of an experimental sample is described, which describes the dependence of stress on relative deformation. An equation of the linear dependence of the tensile strength on the percentage of filament filling has been compiled, which makes it possible to determine the tensile strength of the product at any percentage of the filling of the plastic filament. The assessment is adequately verified by Fisher's criterion. Recommendations for filament filling in prototyping machine parts are given.

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