scholarly journals Linear Dimensional Change and Ultimate Tensile Strength of Polyamide Materials for Denture Bases

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3446
Author(s):  
Bozhana Chuchulska ◽  
Stefan Zlatev
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
The Netherlands ◽  
Artificial Aging ◽  
Dimensional Change ◽  
Storage Conditions ◽  
Control Group ◽  
P Values ◽  
Dimensional Changes ◽  
And Storage

The aim of the current study was to evaluate the dimensional changes and ultimate tensile strength in three polyamide materials for denture bases fabrication through injection molding, subjected to artificial aging and different storage conditions. A total of 333 test specimens fabricated from Biosens (BS; Perflex, Netanya, Israel), Bre.flex 2nd edition (BF; Bredent, Senden, Germany) and ThermoSens (TS; Vertex Dental B.V., Soesterberg, The Netherlands)—n = 111 per material—were equally divided into three groups (n = 37) based on different treatments and storage conditions. Test samples allocated to the “Control group” were not artificially aged and stored in water for 24 h. Both “Treatment 1 group” and “Treatment 2 group” were subjected to thermocycling, the former dehydrated and the latter stored in water between cycle-sets. Linear changes and ultimate tensile strength were measured and analyzed for storage condition and material influence on the outcome variables. A Welch ANOVA test with Games–Howell post-hoc analysis was used to compare the influence of treatments across different materials. Significant differences were found for all three included materials with p values ranging from <0.05 to <0.001 for linear dimensional changes. The magnitude of alterations varied and was large for BS (Perflex, Israel) (ω2 = 0.62) and BF (Bredent, Germany) (ω2 = 0.47) and small but significant for TS (Vertex Dental B.V., The Netherlands) (ω2 = 0.05). However, results seem to fall into clinically acceptable range. Significant differences were also observed for the ultimate tensile strength test with the same range of p-values. All three materials showed different initial ultimate tensile strengths and varying reaction to artificial aging and storage with the lowest alterations observed for BF (Bredent, Germany) (ω2 = 0.05). Within the limitation of this study, it can be concluded that all three materials show different dimensional and mechanical properties when subjected to artificial aging and different storage. Although linear dimensions show significant changes, they seem to be clinically irrelevant, whereas the change in ultimate tensile strength after only 6-month equivalent clinical use was substantial for BS (Perflex, Israel) and TS (Vertex Dental B.V., The Netherlands).

Structure changes and water filtration properties of electrospun polyamide nanofibre membranes

2016 ◽  
Vol 73 (8) ◽  
pp. 1920-1926 ◽  
Author(s):  
N. Daels ◽  
L. Harinck ◽  
A. Goethals ◽  
K. De Clerck ◽  
S. W. H. Van Hulle
Keyword(s):  
Tensile Strength ◽  
Dimensional Change ◽  
Storage Conditions ◽  
Water Filtration ◽  
Dimensional Changes ◽  
Structure Changes ◽  
Bacterial Removal ◽  
Heat Treated ◽  
Filtration Properties

Nanofibre membranes are studied extensively in water treatment. Inappropriate storage, however, could alter their performance, e.g. regarding water filtration. This shows the need for investigating this effect in more detail so as to offer a solution for long-term behaviour and stability. In this study, polyamide nanofibre membranes were treated under different conditions, simulating the diverse storage conditions and to simulate their use in water filtration systems. Under all these different settings, nanofibre properties (scanning electron microscope pictures, dimensional changes, tensile strength) and water filtration performance (clean water permeability (CWP), bacterial removal) were investigated. The results demonstrate that, as soon as the dimensional change of a membrane is &gt;2%, the CWP, tensile strength and bacterial removal significantly decrease. These dimensional changes occurred when the membrane became dry after it had been in contact with water. As such, it is important to keep the membrane either in dry or in wet conditions to store its unique properties. When heat-treated, the membrane had a higher tensile strength and kept its morphology and characteristics better during storage.

Effects of T6 Age Hardening on Microstructure and Mechanical Properties of Al-Si-Cu Cast Aluminium Alloy

2013 ◽  
Vol 770 ◽  
pp. 88-91
Author(s):  
Amporn Wiengmoon ◽  
Pattama Apichai ◽  
John T.H. Pearce ◽  
Torranin Chairuangsri
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Aging Time ◽  
Artificial Aging ◽  
Solution Treatment ◽  
Hot Water ◽  
Age Hardening ◽  
Solution Treated ◽  
Cast Condition

Effects of T6 artificial aging heat treatment on microstructure, microhardness and ultimate tensile strength of Al-4.93 wt% Si-3.47 wt% Cu alloy were investigated. The T6 age hardening treatment consists of solution treatment at 500±5°C for 8 hours followed by quenching into hot water at 80°C and artificial aging at 150, 170, 200 and 230°C for 1-48 hours followed by quenching into hot water. Microstructure was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). XRD and SEM revealed that the microstructure in the as-cast condition consists of primary dendritic α-Al, acicular-plate and globular forms of eutectic Si and intermetallic phases including globular Al2Cu and a flake-shape Al5FeSi. By T6 aging hardening, some intermetallics were dissolved and spheroidized. The volume fraction of eutectic phases in the as-cast, solution-treated, and solution-treated plus aging at 170°C for 24 hours is 17%, 12% and 10%, respectively. TEM results showed that precipitates in under-aging condition at 170° C for 6 hours are in the form of disc shape with the diameter in the range of 7-20 nm. At peak aging at 170°C for 24 hours, thin-plate precipitates with about 3-10 nm in thickness and 20-100 nm in length were found, lengthening to about 30-200 nm at longer aging time. The microhardness and ultimate tensile strength were increased from 71 HV0.05 and 227 MPa in the as-cast condition up to 140 HV0.05 and 400 MPa after solution treatment plus aging at 170°C for 24 hours, and decreased at prolong aging time.

scholarly journals In Vivo Comparison of Ultimate Tensile Strength of Nickel-Titanium Aligning Archwires Exposed to Fluoridated Mouthwash

2020 ◽  
Vol 10 (1) ◽  
pp. 21-26
Author(s):  
Pasupureddi Keerthana ◽  
Prasad Chitra ◽  
Puneeth S B ◽  
LS Lokesh Janardhanam
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Testing ◽  
Nickel Titanium ◽  
Control Group ◽  
Protective Oxide ◽  
Level Of Significance ◽  
Group B ◽  
Niti Wires

Introduction: Orthodontists usually prescribe fluoridated mouthwash to their patients to mitigate risk of dental caries. These mouthwashes may alter the mechanical properties of archwires by dissolving the protective oxide-layer. The aim of the study was to examine the effects of fluoridated mouthwash on ultimate tensile strength of NiTi wires after three months of intra-oral use. Materials & Method: Sixty 0.014” (0.36mm) Nickel-titanium (NiTi) wires (Ormco Corp, Glendora, USA) were divided into three groups: Group A: as-received archwires serving as controls, Group B: intra-oral used wires exposed to placebo mouthwash and Group C: intra-oral used wires exposed to fluoridated mouthwash for a period of 3 months. Each wire was subjected to tensile testing using a table-top tensile testing apparatus. Ultimate tensile strength data was analysed with one-way analysis of variance (ANOVA) and Tukey testing at the 0.05 level of significance. Result: Results showed that amongst tested wires, those exposed to fluoridated mouthwash had least tensile strength (79.45 ± 1.33 N) as compared to wires exposed to placebo mouthwash (99.95 ± 0.91 N) and those in the control group (117.69 ± 0.66 N). The results were statistically significant at p <0.001. Conclusion: Ultimate tensile strength was least for wires exposed to fluoridated mouthwashes for a period of 3 months. Non-fluoridated mouthwashes can be used during the initial phase of leveling and aligning with NiTi wires.

The influence of storage conditions on the physicochemical properties and dimensional accuracy of the alginate impressions

2018 ◽  
Vol 2 (87) ◽  
pp. 68-76
Author(s):  
K. Żelezińska ◽  
M. Nowak ◽  
J. Żmudzki ◽  
C. Krawczyk ◽  
G. Chladek
Keyword(s):  
Tensile Strength ◽  
Design Methodology ◽  
Dimensional Accuracy ◽  
Storage Conditions ◽  
Materials Properties ◽  
Dimensional Changes ◽  
Impression Materials ◽  
Master Model ◽  
Good Relation ◽  
Practical Implications

Purpose: Alginate impression materials are the most commonly used masses for taking impressions. They are characterized by good relation of properties to the price. However, the main problem associated with use of the impression masses is dimensions stability. Manufacturers of alginate masses recommend storage impression without any source of moisture, but dentists frequently store impressions wrapped in a wet materials. This may be the a reason of changes in dimensions and other properties. Moreover, it is recognized, that casting the model in the soon after making impression guarantee better dimensional accuracy. However, models are made usually after 24h. For some masses producers claim unequivocally, that the impressions can be stored for up to 168 h without changing the dimensions. So in this study was investigates how storage conditions affect chosen properties of alginate mass, including the accuracy of the models. Design/methodology/approach: Samples were prepared according to the manufacturer instruction and divided into 5 groups. Measurements were made 20 min after taking the impression and after 24h/168h of storage with/ without the resource of moisture. The measurements of Shore A hardness, tensile strength, mass changes and dimensional changes were made. Accuracies of the dental stone models were investigated with models manufactured after 20 min and 168 h after impressions, in comparison to the master model. Findings: The study showed that the storage conditions and time of storage had influence on properties of alginate impression mass. The resource of moisture has got an influence on dimensions and mass changes, tensile strength, elongation and shore A hardness. The results show that the use of the resource of moisture may be a cause of unfavourable changes in the gypsum model dimensions. Research limitations/implications: The storing of the alginate impressions with the resource of moisture is commonly practiced by the doctors, but it inconsistent with the manufacturer's recommendation. Practical implications: The method storing of the alginate impressions determined not only the materials properties, but also the clinical properties of final products like dentures. Originality/value: The significant of the method of the storing of alginate impression materials on the chosen properties of the materials and the accuracy of the dental stone models were shown.

scholarly journals The Effect of Time and Storage Environment on Dimensional Changes of Acrylic Resin Post Patterns

2015 ◽  
Vol 9 (1) ◽  
pp. 87-90
Author(s):  
Mahmoud Sabouhi ◽  
Saied Nosouhian ◽  
Mansour Dakhilalian ◽  
Amin Davoudi ◽  
Ramin Mehrad
Keyword(s):  
Setting Time ◽  
Acrylic Resin ◽  
Cross Contamination ◽  
Root Canal Therapy ◽  
P Values ◽  
Dimensional Changes ◽  
Post And Core ◽  
Spss Software ◽  
And Storage ◽  
Paired T Test

Introduction : Post and core are needed to regain retentions and functions after endodontic therapies. Also, risk of cross contamination from dental prosthesis is so high. The aim of this study was to compare dimensional changes of acrylic resin patterns (ARP) in three different storing environments. Materials and methods : conventional root canal therapy was done on one first premolar tooth and the canal filled with Guttapercha. 2/3 of the filling was expelled and 30 direct APRs were prepared by Duralay. The samples were divided into 3 groups based on storing environments: water, NaOCl 5% and air. Finally dimensional changes in coronoapical length (CAL), coronal (CD) and apical diameter (AD) of APRs were measured in 7 consecutive times (immediately after polymerization, 1, 2, 4, 8, 24, 48 hours later). All the data were analyzed by Paired T-test and Duncon test using SPSS software ver.13 at significant level of 0.05. Results : After 24 hours, the ARPs, which were stored in air, contracted 0.07, 0.06 and 0.12 mm in AD, CD and CAL; the ARPs, which were stored in water, showed 0.03, 0.06 and 0.12 mm decrease in AD, CD and CAL; But the ARPs, which were stored in NaOCl 5%, showed significant expansion in AD, CD and CAL (0.03, 0.06 and 0.10 mm) (all P values < 0.01). Conclusion : It is better not to use NaOCl for disinfecting; also the best time for storing APRs is 8 hours for water and 2 hours for air environments after setting time.

Effect of Artificial Aging Parametars on Tensile Strength and Microstructure of 7075 Aluminum Alloy

2020 ◽  
Vol 8 (4) ◽  
pp. 37-47
Author(s):  
Mohamad Yahya Nefawy ◽  
Mahmoud Al Asad
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Ultimate Tensile Strength ◽  
Aging Time ◽  
Aging Temperature ◽  
Artificial Aging ◽  
7075 Aluminum Alloy ◽  
Different Temperatures ◽  
Aluminum Alloy 7075

In this research, we studied the effect of change in artificial aging time and temperature on tensile strength and Microstructure for 7075 aluminum alloy, Where samples of aluminum alloy 7075 were treated with artificial aging at different temperatures are 120 ° C, 160 ° C and 200 ° C for 0.5, 1.5, 3, 18, 48 hours. When the 7075 aluminum alloy was artificially aged in of 120 ° C and 160 ° C, the values of ultimate tensile strength (UTS) of the alloy were higher than when it was aged in 200 ° C. By increasing of artificial aging time, the UTS of 7075 aluminum alloy increased, when the aging temperature was 120 ° C or 160 ° C, while the UTS decreased when the aging temperature was 200 ° C. This is due to changes in the microstructure, grain size, and precipitating phases such as MgZn2.

scholarly journals Comparison of Barbed Sutures in Porcine Flexor Tenorrhaphy

Hand ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. 475-478 ◽  
Author(s):  
Alan Sull ◽  
Serkan Inceoglu ◽  
Alicia August ◽  
Stephen Gregorius ◽  
Montri D. Wongworawat
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Ex Vivo ◽  
Biomechanical Testing ◽  
Barbed Suture ◽  
Control Group ◽  
Suture Materials ◽  
Ex Vivo Model ◽  
Normal Tendon ◽  
Minimal Data

Background: Barbed suture use has become more popular as technology and materials have advanced. Minimal data exist regarding performance of the 2 commercially available products, V-LocTM and StratafixTM in tendon repairs. The purpose of this study was to compare gap resistance and ultimate tensile strength of both suture materials and nonbarbed suture in a porcine ex vivo model. Methods: Porcine flexor tendons were harvested and divided into 3 groups of 10 of varying suture material (3-0 PDS™, 3-0 V- V-Loc 180™, or 3-0 Stratafix™). A modified 4-strand cruciate technique was used to repair each tendon. Knotless repair was performed using barbed suture, whereas a buried 6-throw square knot was done using conventional suture. A servohydrolic tester was used for biomechanical testing of linear 2-mm gap resistance and maximum tensile strength. Results: No difference was found in 2-mm gap resistance among the 3 groups. No difference was found in ultimate tensile strength between V-Loc™ (76.0 ± 9.4 N) and Stratafix™ (68.1 ± 8.4 N) repairs, but the ultimate strength of the PDS™ control group (83.4 ± 10.0 N) was significantly higher than that of Stratafix™. Conclusions: Barbed (knotless) and nonbarbed suture repairs demonstrate equivalent 2-mm gap resistance. Stratafix™ repairs show slightly inferior performance to nonbarbed repairs in ultimate tensile strength, although this occurred at gap distances far beyond the 2-mm threshold for normal tendon gliding. Both barbed and nonbarbed 4-strand cruciate flexor tendon repairs may require peripheral repair to withstand physiologic loads.

Weibull Analysis of the Effect of Modified Aging Treatments on Fatigue Life of Cast Aluminium Alloy 354

2013 ◽  
Vol 800 ◽  
pp. 356-360 ◽  
Author(s):  
Salil Sainis ◽  
Aakarshit Kalra ◽  
G. Dinesh Babu ◽  
M. Nageswara Rao
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Ultimate Tensile Strength ◽  
Aluminium Alloy ◽  
Artificial Aging ◽  
Aging Treatment ◽  
Fatigue Loading ◽  
Weibull Analysis ◽  
Compressor Wheel ◽  
Cast Aluminium

Cast aluminium alloy 354 has extensive applications in the automobile industry. Due to its attractive combination of mechanical properties and excellent castability, it is being used in production of automobile components like the compressor wheel for turbochargers. Performance of this component under fatigue loading conditions is a critical issue. The present study explores the possibility of improving the fatigue life of the component by bringing in process changes (i) adopting a two-step aging treatment in place of the normally used single step aging treatment (ii) adopting a lower artificial aging temperature (171°C) instead of the temperature normally used for artificial aging (188°C) while performing T61 treatment. In all cases Weibull analysis of fatigue test results was carried out. Weibull analysis of Ultimate Tensile Strength (UTS) values obtained after artificial aging at 171°C and 188°C was also carried out. Among the four variants of two-step aging treatment carried out, the one consisting of 100°C for 5 hours followed by 170°C for 5 hours was found to have the best characteristic fatigue life for the components. The modified T61 treatment where aging was carried out at 171°C instead of the normally used 188°C yielded better characteristic fatigue life as well as better Ultimate Tensile Strength (UTS).

scholarly journals Evaluation of TIG dental welding applied to Ti-6Al-4V alloys with different diameters: Analysis by Ultimate Tensile Strength, Vickers Hardness, and Finite Element Method

2021 ◽  
Vol 10 (9) ◽  
pp. e29110916481
Author(s):  
Morgana Guilherme de Castro Silverio ◽  
Gabriela Lima Menegaz ◽  
Cleudmar Amaral Araújo ◽  
Washington Martins da Silva Júnior ◽  
Paulo Cézar Simamoto Júnior
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Vickers Hardness ◽  
Control Group ◽  
Finite Element Models ◽  
Limited Information ◽  
Experimental Conditions ◽  
Radiographic Inspection ◽  
Different Diameters

There is limited information in literature regarding the accomplishment of Ti-6Al-4V TIG joints welded in prefabricated bars applied to dentistry. Evaluate the ultimate tensile strength and Vickers hardness of Ti-6Al-4V alloy subjected to TIG (Tungsten Inert Gas) welding technique in different diameters. Material and methods: Forty-five specimens were prepared and divided into 5 groups: control group (CG) (n=5), with intact bars in a diameter of 3.0mm, and groups TIG2.5, TIG3, TIG4, TIG5 (n=10) with diameters of 2.5, 3, 4 and 5 mm respectively, welded with TIG in a pulse of 10(ms) and in a depth of 3(A). The specimens were tested by both radiographic inspection and penetrating liquids. After that, they were tested by ultimate tensile strength (UTS) and the elongation percentage (EP) was obtained. Images from fractured samples were taken and the welded areas percentage (WAP) was calculated. Random images were also taken by scanning electron microscope (SEM). Vickers hardness was obtained for base metal (BM), Heat affected zone (HAZ) and Welded zone (WZ). Finite element models were constructed. One-way Anova, Dunnet and Tukey tests (α=.05) were used for statistical analysis of UTS, WAP and EP for different groups and for differences in regions (BM, HAZ and WZ). Finite element models were developed in a workbench environment with boundary conditions simulating a tensile test. The majority of the specimens showed internal voids on radiographic inspection, but porosities or groves were not observed on their surface on penetrant liquid test. Most of the samples fractured in the welded area. The 1-way ANOVA showed significant differences among the groups for UTS, WAP and EP values (P<.001). The Dunnett test showed that TIG3, TIG4 and TIG5 groups had lower UTS values than those of the CG, but TIG2.5 group had no statistical difference in relation to CG. The 1-way ANOVA showed significant differences among the regions (P<.001) for Vickers hardness. Under the experimental conditions described, the diameter of 2.5 seems to be the best option for joining prefabricated rods in this kind of union and in this regulation of the machine.

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