scholarly journals Influence of Thermocycling and Sealer Coating Application on Shore Hardness of Soft Denture Lining Material

2021 ◽  
Vol 9 (D) ◽  
pp. 279-284
Author(s):  
Ismet Danial Nasution ◽  
Haslinda Z. Tamin ◽  
Ariyani Ariyani ◽  
Ivana Ivana
Keyword(s):  
Aging Process ◽  
Hardness Test ◽  
Shore Hardness ◽  
Significance Level ◽  
Coating Application ◽  
Lining Material ◽  
Silicon Based ◽  
Simulation Time ◽  
Functional Problems ◽  
Mechanical Barrier

BACKGROUND: One of the properties of the soft denture lining (SDL) material that needed to overcome the functional problems is softness. Loss of softness due to the aging process and to extend the duration of use, sealer coating was developed to maintain its softness. Sealer coating acts as mechanical barrier to provide protection against aging of SDL materials. AIM: This study aims to determine the influence of thermocycling and sealer coating application on the shore hardness of the acrylic-based and silicone-based auto-polymerizing soft denture lining materials. MATERIALS AND METHODS: Materials that were used in this study are acrylic-based auto-polymerizing SDL (Durabase Soft, Reliance Dental Manufacturing LLC, Illinois, USA) and silicone-based auto-polymerizing SDL (Mollosil, Detax GmbH, Ettlingen, Germany). In this study, we used monopoly as sealer coating for acrylic-based auto-polymerizing SDL and varnish for silicone-based auto-polymerizing SDL. Thermocycling was performed for 2000 cycles for a 2-year simulation time. For shore hardness test, a total of 40 discs shaped samples were made with a diameter of 35 mm and a thickness of 6 mm. The samples were divided into eight groups (n = 5), namely, the uncoated and non-thermocycling acrylic-based auto-polymerizing SDL, the coated and non-thermocycling acrylic-based auto-polymerizing SDL, the uncoated and thermocycling acrylic-based auto-polymerizing SDL, the coated and thermocycling acrylic-based auto-polymerizing SDL, the uncoated and non-thermocycling silicone-based auto-polymerizing SDL, the coated and non-thermocycling silicone-based auto-polymerizing SDL, the uncoated and thermocycling silicone-based auto-polymerizing SDL, and the coated and thermocycling silicone-based auto-polymerizing SDL. The hardness test was carried out using the shore A durometer. RESULTS: The obtained data were tested using the independent t-test with a significance level of p < 0.05. The results showed that there was a significant effect between coated and uncoated acrylic-based SDL group that underwent thermocycling and in the silicone-based SDL group. The study showed that the hardness value was lower in both coated acrylic-based and silicone-based SDL groups compared to the non-coated group, so it can be concluded that the sealer coating is able to protect the hardness of SDL material against aging with a thermocycling simulation. The results also showed that there was a significant effect of thermocycling on the hardness of the material both in the coated acrylic-based SDL group, the uncoated acrylic-based SDL group, and the uncoated silicone-based SDL group. Study also showed that there was no significant effect of thermocycling in the coated silicone-based SDL group. CONCLUSION: Based on the results, it can be concluded that the use of sealer coating can maintain the hardness properties of both acrylic-based SDL and silicon-based self-polymerizing SDL so that it can increase the durability of SDL materials. However, the effect of sealer coating in protecting the hardness of SDL materials against aging was more evident in the silicone-based SDL group.

scholarly journals Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

2007 ◽  
Vol 18 (1) ◽  
pp. 20-23 ◽  
Author(s):  
João Vicente Baroni Barbizam ◽  
Matheus Souza ◽  
Doglas Cecchin ◽  
Jakob Dabbel
Keyword(s):  
Root Canal ◽  
In Vitro Study ◽  
Root Canal Sealer ◽  
Human Teeth ◽  
Significance Level ◽  
Working Length ◽  
Group 3 ◽  
Group 2 ◽  
Silicon Based

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5% NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

scholarly journals A Characteristic of Selected Properties of Vulcanised Rubber Elements Used on the “Izabel” Inland Vessel

2018 ◽  
Vol 1 (1) ◽  
pp. 675-679
Author(s):  
Patrycja Pawłowska ◽  
Zbigniew Matuszak ◽  
Katarzyna Sosik ◽  
Mária Chovancová
Keyword(s):  
Hardness Test ◽  
Weather Conditions ◽  
General Concept ◽  
Operating Conditions ◽  
Shore Hardness ◽  
Final Phase ◽  
High Elasticity ◽  
Static And Dynamic Loads ◽  
Main Components ◽  
Elastic Deformability

Abstract Vulcanised rubber as a complex system is made from the basic component being virgin rubber and various components amounting to 10-15 per cent or even more. The material gains its most valuable properties in the final phase of processing i.e. vulcanisation. In mechanical as well as automotive engineering it is important for vulcanised rubber to be resistant to grease, oil and fuel in high operating temperatures. Being one of the very valuable isolation materials, vulcanised rubber is also characterised by dielectric and elastic properties as well as distinguished resistance to operating conditions (high/low temperature, weather conditions). All the above mentioned applications of vulcanised rubbers are also found in the shipyard industry. Their use is also very much predicated on the properties such as: ability to attenuate mechanical vibrations, high elasticity, considerable elastic deformability under static and dynamic loads, low permeability of water and gas, resistance to various chemicals, and other. The purpose of this article was to determine the hardness of vulcanised rubber samples obtained from various places on the “Izabel” inland barge. The scope of the study covered sampling and preparing the samples for testing (i.e. cleaning and degreasing the samples). Then, the hardness of the samples was measured using the Shore hardness test. The first part of the article presents the general concept of vulcanised rubber, its main components, properties, applications, and ageing. The second part focuses on the research scope and measuring the hardness of vulcanised rubber samples obtained from the “Izabel” inland barge.

scholarly journals Mechanical Properties of Anatomic Finishing Files: XP-Endo Finisher and XP-Clean

2018 ◽  
Vol 29 (2) ◽  
pp. 208-213 ◽  
Author(s):  
Eduarda Santiago Vaz-Garcia ◽  
Victor Talarico Leal Vieira ◽  
Natasha Pereira da Silva Ferreira Petitet ◽  
Edson Jorge Lima Moreira ◽  
Hélio Pereira Lopes ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Visual Inspection ◽  
Hardness Test ◽  
Cyclic Fatigue ◽  
Radius Of Curvature ◽  
Weibull Analysis ◽  
Micro Hardness ◽  
Significance Level ◽  
Hardness Tester ◽  
Improved Performance

Abstract The aim of the present study was to evaluate the cyclic fatigue of two anatomic finishing files: XP-Endo Finisher and XP-Clean. Roughness pattern and the micro-hardness of the files were also assessed. Instruments were subjected to cyclic fatigue resistance measuring the time to fracture in an artificial stainless-steel canal with a 60° angle and a 5-mm radius of curvature. The fracture surface of all fragments was examined with a scanning electron microscope. The roughness of the working parts was quantified by using a profilometer and the micro-hardness test was carried out using a Vickers hardness tester. Results were statistically analyzed using a student´s t-test at a significance level of P < 0.05. Weibull analysis was also performed. XP-Endo Finisher presented significantly longer cyclic fatigue life than XP-Clean instruments (P<0.05). XP-Endo Finisher was able to withstand 1000% more cycles to fracture when compared to XP-Clean instruments. SEM visual inspection of the fracture surfaces revealed fractographic characteristics of ductile fracture in all tested instruments; wide-ranging forms of dimples were identified and no plastic deformation in the helical shaft of the fractured instruments was observed. When mean life was compared XP-Endo Finisher lasted longer than XP-Clean with a probability of 99.9%. XP-Endo Finisher instruments also exhibited significantly lower roughness than XP-Clean instruments (P<0.05). No differences in the micro-hardness was observed between the files (P>0.05). It can be concluded that XP-Endo Finisher instruments showed improved performance when compared with XP-Clean instruments, demonstrating higher cyclic fatigue resistance and lower roughness.

scholarly journals Chemical Composition and Microhardness of Human Enamel Treated with Fluoridated Whintening Agents. A Study in Situ

2017 ◽  
Vol 11 (1) ◽  
pp. 34-40
Author(s):  
Thais de Mendonça Petta ◽  
Yasmin do Socorro Batista de Lima Gomes ◽  
Renata Antunes Esteves ◽  
Kelson do Carmo Freitas Faial ◽  
Roberta Souza D`Almeida Couto ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Morphological Changes ◽  
Dental Enamel ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Control Group ◽  
High Concentration ◽  
Significance Level ◽  
Before And After

Background: Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. Objective: Assess in situ the effects of high-concentration hydrogen peroxide with and without fluoride on human dental enamel using the ion chromatography test (IC) and the Knoop hardness test (KHN). Material and Methods: Nineteen enamel specimens were prepared using third human molars. These specimens were fixed on molars of volunteers and were divided into groups: OP38-Opalescence Boost PF38%, PO37-Pola Office 37.5% and CO-Control group. For chemical analysis (n= 3), the dentin layer was removed, keeping only the enamel, which was subjected to acidic digestion by microwave radiation. It was necessary to perform sample dilutions for the elements fluorine (F), calcium (Ca) and phosphorus (P) for quantification using the IC test. The KHN (n= 5) was performed before and after the treatments. Five indentations were made, separated by 100 µm, for each specimen using a load of 25 gf for 5 seconds in the microdurometer. The data were analyzed using ANOVA with a 5% significance level. Results: The OP38 group had the largest concentrations of F, Ca and P ions. The PO37 group showed the lowest concentrations of F and Ca ions. The average KHN was not significantly different between the OP38 and PO37 groups. Conclusion: Enamel whitened with hydrogen peroxide containing fluoride had greater concentrations of F, Ca and P ions. The presence of fluoride in the whitening agent did not influence the enamel microhardness.

scholarly journals EFFECT OF ARTIFICIAL WEATHERING ON PHYSICAL AND MECHANICAL PROPERTIES OF WOOD

2021 ◽  
Vol 45 ◽  
Author(s):  
Vinicius Borges de Moura Aquino ◽  
Marilia Silva Bertolini ◽  
Cesar Augusto Galvão de Morais ◽  
Tiago Hendrigo Almeida ◽  
Diego Henrique Almeida ◽  
...  
Keyword(s):  
Aging Process ◽  
Physical And Mechanical Properties ◽  
Wood Properties ◽  
Significance Level ◽  
Artificial Weathering ◽  
Performance Loss ◽  
Mechanical And Physical Properties ◽  
Mechanical Factors ◽  
Strength In Compression ◽  
Weathering Effects

ABSTRACT When wood is exposed outdoors, a combination of chemical and mechanical factors and solar radiation contribute to what is described as weathering, being the main degradation agent in this environment. This paper aims to investigate the effect of artificial weathering on mechanical and physical properties of Eucalyptus sp. and Cupiúba (Goupia glabra) woods simulating natural weathering effects. Samples were aged in UV radiation chamber with humidity and temperature control for 100, 200, 300 and 400 hours, considering aging cycles according to ASTM G154 (2006). Wood properties investigated were Conventional value of strength in static bending (fM), Modulus of elasticity in static bending (EM), strength in compression parallel to grain (fc0) and Janka Hardness (fH) according to ABNT NBT 7190 (1997). Effects of artificial weathering on wood properties were evaluated by statistical analysis at 5% significance level. Most of the wood properties investigated did not present significant changes with the aging performed, however, it was noted a decrease in the absolute values of the wood properties absolute values during the aging process. Only fH of Cupiúba wood aged for 100 and 200 hours presented significative performance loss at the significance level considered, which can be related to changes on the wood surface due to weathering exposure.

scholarly journals Physical Properties and Failure Analysis for Bolts in the Diaphragm Valve by Micro Morphology and Metallographic Test

2021 ◽  
Vol 2083 (2) ◽  
pp. 022103
Author(s):  
Dungui Zuo ◽  
Zhongwei Zhang ◽  
Yunting Lai ◽  
Guodong Zhang
Keyword(s):  
Corrosion Test ◽  
Aging Process ◽  
Hardness Test ◽  
Intergranular Cracking ◽  
Diaphragm Valve ◽  
Valve Stem ◽  
Stem Fracture ◽  
Corrosion Pits ◽  
Steel Bolts ◽  
Micro Morphology

Abstract The reasons leading to the fracture of 17-4PH stainless steel bolts in the isolation valve of a power plant was analysed by means of morphology analysis, chemical analysis, hardness test, metallographic test, pitting corrosion test and intergranular corrosion test, SEM and other detection means. The results show that there are many corrosion pits on the surface of the valve stem in the seawater system, the corrosion pits is extend and propagation in intergranular cracking. The main reasons to valve stem fracture are the low corrosion resistance of the material and the improper aging process of heat treatment.

scholarly journals Annealing effect of micro-alloying on the microstructure and properties of Cu-10Zn alloy

2019 ◽  
Vol 136 ◽  
pp. 01015
Author(s):  
Wei Chen ◽  
Jiarui Hu ◽  
Yi Xie ◽  
Hengyi Zhou ◽  
Chao Feng ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Aging Process ◽  
Conductivity Measurement ◽  
Hardness Test ◽  
Precipitation Strengthening ◽  
Strengthening Effect ◽  
Electrical Conductivity Measurement ◽  
Microstructure And Properties ◽  
Transmission Electron ◽  
The Matrix

The effect of Fe and P (Ni and Si) on the microstructure and properties of Cu-10Zn alloys has been investigated using hardness test, electrical conductivity measurement, optical microscopy and transmission electron microscopy. γ-Fe precipitates formed during the aging process, but there is almost no effect of precipitation strengthening on the Cu-Zn-Fe-P alloy and sparsely Fe3P precipitates existed in the matrix. After homogenization treatment at 900°C for 2h, hot rolling by 80%, cold rolling by 80%, and ageing treatment at 400°C for 30min, Cu-Zn-Ni-Si alloy obtained good combinations of hardness (219.8HV) and electrical conductivity(28.2%IACS). Ni2Si precipitates formed during aging process and the crystal orientation relationship between matrix and precipitates is:(200)α || (100)δ, [100]α || [010]δ,. Compared with Cu-Zn-Fe-P, Cu-Zn-Ni-Si has finer grains, and the precipitation strengthening effect is more obvious.

The Physical Properties of PMMA Denture base Resin Incorporated with Vanillin

2018 ◽  
Vol 773 ◽  
pp. 338-343 ◽  
Author(s):  
Kittituch Vongvachvasin ◽  
Sroisiri Thaweboon ◽  
Pornkiat Churnjitapirom ◽  
Saowaros Kaophun ◽  
Natdhanai Chotprasert
Keyword(s):  
Flexural Strength ◽  
Physical Properties ◽  
Vickers Hardness ◽  
Flexural Modulus ◽  
Surface Hardness ◽  
Hardness Test ◽  
Antimicrobial Effect ◽  
Denture Base ◽  
Significance Level ◽  
Significant Difference

Long-term use of a denture base can be a reservoir of microbes due to porosities and mechanical wear of denture surfaces. Vanillin has an antimicrobial effect. However, its influence on physical properties after incorporated in PMMA has not yet been evaluated. The purpose of this study was to investigate physical properties of PMMA by incorporating vanillin in different concentrations. Material and method. There were three groups of PMMA with ten specimens per group. Flexural strength and flexural modulus were tested by using a 3-point bending machine, and surface hardness was determined by Vickers hardness test. One-way ANOVA and Kruskal Wallis tests were used to analyze all data at 0.05 significance level. Result. The 0.1% vanillin group yielded a significant difference in Vickers hardness number (17.15 HV) as compared to 0.5% vanillin group (16.30 HV) and without vanillin (15.30 HV). In contrast, the flexural strength and modulus showed no significant difference among test groups upon incorporation of vanillin. Conclusion. The vanillin incorporated PMMA group demonstrated higher surface hardness, compared to the group without vanillin. In addition, there were no significant differences in flexural strength and flexural modulus among the three groups. This study also found no adverse effect in physical properties of the vanillin incorporated PMMA.

scholarly journals Post-Weld Heat Treatment Effects on Mechanical Properties and Microstructure of AA6061-T6 Butt Joints Made by Friction Stir Welding at Right Angle (RAFSW)

2019 ◽  
Vol 3 (2) ◽  
pp. 42 ◽  
Author(s):  
Mahboubeh Momeni ◽  
Michel Guillot
Keyword(s):  
Friction Stir Welding ◽  
Aging Process ◽  
Artificial Aging ◽  
Low Cost ◽  
Hardness Test ◽  
Industrial Sector ◽  
Fusion Welding ◽  
Butt Joints ◽  
Friction Stir ◽  
Weld Heat

Friction stir welding (FSW) provides users with many advantages over fusion welding techniques. Nevertheless, it is not widely employed in current industry mainly due to high equipment costs and royalties. To overcome these issues, a low-cost FSW technique operated at a right angle, called RAFSW, has recently been developed by our research team. To make the RAFSW technique reliable for potential users, we are going to analyze the effect of various post-weld heat treatments (PWHT) on the mechanical and physical properties of the RAFSW joints. To this end, optimized process parameters are used to weld butt joints of an AA6061-T6 alloy. The joints were characterized using a tensile test, a micro-hardness test, and metallography techniques. The most efficient aging time was obtained for various aging temperatures. Moreover, it was found that artificial aging at 220 °C for 30 min could be used as a fast and cost-effective artificial aging PWHT for the industrial sector. In addition, the repeatability of the PWHTs were demonstrated by studying the effect of waiting time prior to the artificial aging. Finally, it was revealed that a single fast artificial aging process is more beneficial than solubilizing followed by an artificial aging process in terms of tensile properties, consumed time, and cost.

scholarly journals Sustainable Thermosets Obtained by Copolymerization of Humins with Triglycidyl Ether of Phloroglucinol

2020 ◽  
Vol 9 (2) ◽  
pp. 1
Author(s):  
Roxana Dinu ◽  
Alice Mija
Keyword(s):  
Mechanical Properties ◽  
Hardness Test ◽  
Well Being ◽  
Great Emphasis ◽  
Industrial Wastes ◽  
Waste Valorization ◽  
Shore Hardness ◽  
Physico Chemical ◽  
Hardness Values ◽  
Very High

The environmental pollution is growing continuously - causing a worldwide problem. Production and use of petroleum-based materials but also huge quantities of industrial wastes are important factors that affect the well-being of the environment. New scientific researches place great emphasis on waste valorization, and also on developing new environmentally friendly bio-based materials. In this work we focus on the valorization of humins, a biorefinery side product, by its copolymerization with a bio-based triepoxide. In this manner we produce materials with a very high bio-based carbon content (BCC) &raquo; 94%. The physico-chemical and mechanical properties of the cured bio-based resins were investigated using different technics as TGA, DMA, Shore hardness test, water absorption and solvents resistance. It was revealed that the obtained materials present very good mechanical properties with values of E&rsquo; in glassy region &raquo; 3.7&ndash;5 GPa. The tan &delta; &ndash; maxima of the three humins-based resins are ranging from 122 to 154 &deg;C. The thermosets&rsquo; hardness values &raquo; 82&ndash;85 SD confirm the stiffness of these materials.

Sign in / Sign up

Export Citation Format

Share Document