scholarly journals Effect of cementation on the mechanical behavior of a nanoceramic resin

Cerâmica ◽  
2020 ◽  
Vol 66 (379) ◽  
pp. 236-242 ◽  
Author(s):  
A. D. Nogueira ◽  
P. H. Corazza ◽  
O. E. Pecho ◽  
M. M. Perez ◽  
M. Borba
Keyword(s):  
Flexural Strength ◽  
Mechanical Behavior ◽  
Vickers Microhardness ◽  
Compressive Load ◽  
Strength Test ◽  
Load Test ◽  
Resin Cement ◽  
Restorative Material ◽  
Weibull Analysis ◽  
Strength Tests

Abstract Conventional flexural strength tests of restorative materials neglect the effect of essential variables that can affect their mechanical behavior. The purpose of this study was to evaluate the effect of cementation on the mechanical behavior of a nanoceramic resin. A nanoceramic resin (LU) and a leucite-reinforced glass-ceramic (IE) were evaluated. Non-cemented specimens of the materials were produced and subjected to biaxial flexural strength test ( σ f , n = 30 ). Cemented specimens were constituted of the restorative material bonded with resin cement onto a dentin analog substrate. Cemented specimens were subjected to the monotonic compressive load test ( L f , n = 20 ). Vickers microhardness (HV) and translucency parameter (TP) of the materials were characterized. Data were analyzed using t-test (σf and TP), Mann-Whitney test (Lf and HV), and Weibull analysis (σf and Lf, α = 0 . 05). Non-cemented LU showed higher σf and Weibull modulus (m) than IE. When cemented to the substrate, LU showed higher Lf than IE; however, the m-value was similar among groups. LU showed lower HV than IE and higher TP values. Cementation influenced the mechanical behavior and failure mode of the nanoceramic resin.

Impact of Silane-containing Universal Adhesive on the Biaxial Flexural Strength of a Resin Cement/Glass-ceramic System

2019 ◽  
Vol 44 (2) ◽  
pp. 200-209 ◽  
Author(s):  
F Murillo-Gómez ◽  
RB Wanderley ◽  
MF De Goes
Keyword(s):  
Flexural Strength ◽  
Glass Ceramic ◽  
Resin Cement ◽  
Weibull Analysis ◽  
Ceramic System ◽  
Universal Adhesive ◽  
Bonded Interface ◽  
Biaxial Flexural Strength ◽  
Digital Caliper ◽  
One Way Anova

SUMMARY The aim of this study was to determine whether using a silane-containing universal adhesive as a silane primer in glass-ceramic/resin cement systems affects biaxial flexural strength (BFS) and bonded interface integrity after loading. Glass-ceramic (IPS e.max CAD, Ivoclar/Vivadent, Schaan, Liechtenstein) disc-shaped specimens (6.5±0.1mm in diameter, 0.5±0.1mm thick) were etched with 5% hydrofluoric acid (HF) for 20 seconds and divided into four groups of 30 specimens, to be treated as follows: 1) One bottle silane primer (RCP); 2) Separate application of silane and adhesive (RCP+SB); 3) Silane-containing universal adhesive (SBU); 4) No treatment (C). After silanization, all specimens were resin cement– coated and polymerized for 40 seconds. Each specimen layer was measured, as well as each assembly's thickness, using a digital caliper and scanning electron microscope (SEM). Specimens were stored for 24 hours and submitted to a BFS test (1.27 mm/min). BFS values were calculated using the bilayer disc-specimen solution. Bonded interfaces were analyzed on fractured fragments using SEM. One-way ANOVA and Tukey tests (α=0.05) were applied, as well as the Weibull analysis. Factor “silane treatment” was statistically significant (p<0.0001). RCP+SB (372.2±29.4 MPa) and RCP (364.2±29.5 MPa) produced significantly higher BFS than did the C (320.7±36.3 MPa) or SBU (338.0±27.1 MPa) groups. No differences were found in the Weibull modulus (m: RCP: 10.1-17.3; RCP+SB: 10.1-17.0; SBU: 12.3-22.4; C: 7.4-12.9). Bonded interface analysis exhibited ceramic-cement separation (SBU, C) and voids within the resin cement layer (all groups). Neither the ceramic/cement system's BFS nor its bonded interface stability were improved by SBU after loading.

Assessment of post-heat behavior of cement mortar incorporating silica fume and granulated blast-furnace slag

2020 ◽  
Vol 11 (2) ◽  
pp. 221-246
Author(s):  
Ghasem Pachideh ◽  
Majid Gholhaki
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Blast Furnace Slag ◽  
Strength Test ◽  
Content Type ◽  
Granulated Blast Furnace Slag ◽  
Cement Mortars ◽  
Strength Tests ◽  
Pozzolanic Materials ◽  
Furnace Slag

Purpose With respect to the studies conducted so far and lack of researches on the post-heat behavior of cement mortars containing pozzolanic materials, the purpose of this paper is to investigate the post-heat mechanical characteristics (i.e. compressive, tensile and flexural strength) of cement mortars containing granulated blast-furnace slag (GBFS) and silica fume (SF). In doing so, selected temperatures include 25, 100, 250, 500, 700 and 9000c. Last, the X-ray diffraction test was conducted to study the microstructure of mixtures and subsequently, the results were presented as power-one mathematical relations. Design/methodology/approach Totally, 378 specimens were built to conduct flexural, compressive and tensile strength tests. Accordingly, these specimens include cubic and prismatic specimens with dimensions of 5 × 5 × 5 cm and 16 × 4 × 4 cm, respectively, to conduct compressive and flexural strength tests together with briquette specimen used for tensile strength test in which cement was replaced by 7, 14 and 21 per cent of SF and GBFS. To study the effect of temperature, the specimens were heated. In this respect, they were heated with a rate of 5°C/min and exposed to temperatures of 25 (ordinary temperature), 100, 250, 500, 700 and 900°C. Findings On the basis of the results, the most profound effect of using GBFS and SF, respectively, takes place in low (up to 250°C) and high (500°C and greater degrees) temperatures. Quantitatively, the compressive, tensile and flexural strengths were enhanced by 73 and 180 per cent, 45 and 100 per cent, 106 and 112 per cent, respectively, in low and high temperatures. In addition, as the temperature elevates, the particles of specimens containing SF and GBFS shrink less in size compared to the reference specimen. Originality/value The specimens were cured according to ASTMC192 after 28 days placement in the water basin. First, in compliance with what has been specified by the mix design, the mortar, including pozzolanic materials and superplasticizer, was prepared and then, the sampling procedure was conducted on cubic specimens with dimension of 5 × 5 × 5 mm for compressive strength test, prismatic specimens with dimensions of 16 × 4 × 4 mm for flexural strength test and last, briquette specimens were provided to conduct tensile strength tests (for each temperature and every test, three specimens were built).

scholarly journals Influence of furnace type in the crystallization of lithium disilicate on bond strength and flexural strength

2019 ◽  
Vol 18 ◽  
pp. e191405
Author(s):  
Karla Zancope ◽  
Thácio de Castro ◽  
Lucas do Nascimento Tavares ◽  
Marcel Santana Prudente ◽  
Flávio Domingues das Neves
Keyword(s):  
Flexural Strength ◽  
Bond Strength ◽  
Storage Time ◽  
Lithium Disilicate ◽  
Strength Test ◽  
Resin Cement ◽  
Holding Time ◽  
Control Group ◽  
Representative Specimen ◽  
Significant Difference

Aim: The crystallization step is required for lithium disilicate ceramics to change color, improve the mechanical properties and yield material to support mouth loading. Several furnaces could complete the crystallization process. This study evaluated the flexural and bond strength of lithium disilicate ceramics crystallized by different furnaces with the presence or not of vacum and different holding time. Methods: Forty lithium disilicate samples were divided into two groups: Programat P300 - control group with vacuum and holding time 7 minutes (CG) and FVPlus- experimental group and without vacuum and holding time 25 minutes (EG) and submitted to 2 experimental tests: 3-point flexural strength test and micro shear bond strength test (µSBS). For this test, the surface of the samples was treated and 1mm² of resin cement was applied on the surface. The samples were stored in artificial saliva over 2 time periods (24 hours: T0; 1-month storage: T1). To analyze the morphologic crystals of the ceramics tested, one representative specimen from each group were analyzed by using Scanning Electron Microscopy (SEM). Results: There was no significant difference in 3-point flexural strength test between groups CG and EG (p= 0.984). The µSBS results showed no statistical difference between groups, considering different storage time. There was no difference in the 3-point flexural strength and μSBS for lithium disilicate samples regardless of heat treatment of furnace type. The storage time had no influence on the μSBS. No differences were noted in the shape and size of these crystals when comparing the furnace analyzed by SEM images. Conclusion: Different furnaces did not influence the flexural and bond strength of lithium disilicate ceramics.

scholarly journals Effect of Carbamide Peroxide Bleaching Gel on Composite Resin Flexural Strength and Microhardness

2013 ◽  
Vol 24 (3) ◽  
pp. 263-266 ◽  
Author(s):  
Gabriel Rodrigues Hatanaka ◽  
Filipe de Oliveira Abi-Rached ◽  
Antonio Alves de Almeida-Junior ◽  
Carlos Alberto dos Santos Cruz
Keyword(s):  
Flexural Strength ◽  
Vickers Microhardness ◽  
Composite Resin ◽  
Testing Machine ◽  
Distilled Water ◽  
Restorative Material ◽  
Carbamide Peroxide ◽  
Peroxide Bleaching ◽  
Post Hoc ◽  
Bleaching Treatment

This study investigated the effect of 16% carbamide peroxide (Whiteness Perfect/FGM) on the Vickers microhardness and flexural strength of the restorative composites Filtek Z100 (hybrid), Filtek Z350 (nanofill), Brilliant (micro-hybrid) and Opallis (micro-hybrid). Disc-shaped (4x2 mm; n=5) and bar-shaped (12x2x1 mm; n=10) specimens of each restorative material were randomly divided into 2 groups: (G1) 16 weeks stored in distilled water; (G2) 16 weeks stored in distilled water, with 16% carbamide peroxide application during 6 h per day for the last 4 weeks. The mechanical properties were evaluated using a Vickers microhardness tester and a mechanical testing machine. Data were analyzed by two-way ANOVA and Tukey's (HSD) post-hoc test (α=0.05). Filtek Z100 presented the highest microhardness value, followed by Filtek Z350 and finally by Brilliant and Opallis (p=0.00). Filtek Z100 and Brilliant exhibited the highest flexural strength value, followed by Filtek Z350 and Opallis (p=0.00). Bleaching treatment decreased significantly microhardness of Brilliant and Opallis (p=0.00). The flexural strength of all studied materials was not affected by the home bleaching (p=0.28).

scholarly journals Ethanol Postpolymerization Treatment for Improving the Biocompatibility of Acrylic Reline Resins

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Cristina B. Neves ◽  
Luís P. Lopes ◽  
Helena F. Ferrão ◽  
Joana P. Miranda ◽  
Matilde F. Castro ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Vickers Microhardness ◽  
Recent Literature ◽  
Human Fibroblasts ◽  
Hot Water ◽  
Residual Monomer ◽  
Lactate Dehydrogenase Release ◽  
Dental Office ◽  
Strength Tests

Objective. To evaluate the effect of postpolymerization treatment based on ethanol-aqueous solutions on the residual monomer (RM) content, flexural strength, microhardness, and cytotoxicity of hard chairside reline resins (Kooliner, Ufi Gel Hard).Methods. After polymerization, specimens were immersed in water, 20%, 50%, or 70% ethanol solutions at 23°C or 55°C for 10 minutes. Controls were left untreated. HPLC was used for the determination of RM content. Specimens were submitted to Vickers microhardness and 3-point loading flexural strength tests. Cytotoxicity of resin eluates was determined on human fibroblasts by assessing cellular mitochondrial function and lactate dehydrogenase release.Results. Higher concentrations of ethanol promoted lower RM content at 55°C in both materials. The mechanical properties were maintained after 50% and 20% ethanol treatments in Kooliner and Ufi Gel Hard, respectively. Specimens submitted to those treatments showed significant reduction on cytotoxicity compared to immersion in hot water, the treatment of choice in the recent literature.Significance. Immersion of relined dentures in specific ethanol solutions at 55°C for 10 minutes can be considered an effective postpolymerization treatment contributing to increase materials biocompatibility. The proposed protocol is expeditious and easy to achieve with simple equipment in a dental office.

A study of Al2Ti precipitation in a Cu-modified Al3Ti alloy

1992 ◽  
Vol 7 (4) ◽  
pp. 876-882 ◽  
Author(s):  
L. Potez ◽  
A. Loiseau ◽  
S. Naka ◽  
G. Lapasset
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Mechanical Behavior ◽  
Vickers Microhardness ◽  
High Resolution Electron Microscopy ◽  
Nucleation And Growth ◽  
Ti Alloy ◽  
Hardening Effect ◽  
Resolution Electron

An equilibrium precipitation of Al2Ti is shown to occur within a Cu-modified Al2Ti alloy having the L12 structure. This precipitation is analyzed by conventional and high resolution electron microscopy and some insights are given concerning the mechanisms of nucleation and growth of Al2Ti within the L12 matrix. In the meantime, Vickers microhardness tests have been performed as a first approach to the mechanical behavior of this alloy and the results are compared to measurements obtained in an actual single-phased L12 compound. The Al2Ti precipitation seems to have an important hardening effect.

scholarly journals EARLY STRENGTH TESTING AFTER ACL RECONSTRUCTION IMPACTS ISOKINETIC STRENGTH PERFORMANCE AT TIME OF RETURN TO SPORT

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0011
Author(s):  
Adam Weaver ◽  
Dylan Roman ◽  
Maua Mosha ◽  
Nicholas Giampetruzzi
Keyword(s):  
Test Performance ◽  
Knee Extension ◽  
Strength Test ◽  
Strength Testing ◽  
Isokinetic Strength ◽  
Rehabilitation Process ◽  
Strength Performance ◽  
Knee Extension Strength ◽  
Isometric Knee Extension ◽  
Strength Tests

Background: The standard of care in ACL reconstruction (ACLR) typically involves standardized strength testing at 6 months or later to assess a patient’s readiness to return to play (RTP) using isokinetic and isometric testing, and functional strength testing. Recent literature suggests that isokinetic knee extension strength should demonstrate 89% limb symmetry index (LSI) or greater prior to returning to sport. However, there is little known on the effects of strength testing early in the rehabilitation process and the relationship to strength test performance at time of RTP. Purpose: The purpose of this study was to examine how early post-operative strength test performance impacts isokinetic strength outcomes at RTP testing in adolescents. Methods: The retrospective cohort study included patients undergoing primary ACLR between 12 and 18 years of age, early post-operative strength measures, and isokinetic dynamometer strength at RTP from July 2017 and April 2019. Data was dichotomized into desired outcomes at 3 months: >70% isometric knee extension LSI, > 20 repetitions on anterior stepdown test (AST), > 90% LSI Y Balance. At RTP testing, isokinetic knee extension strength data was categorized into >89% LSI at 3 speeds (300, 180, 60°/sec). Chi square testing and odds ratio statistics were used to examine association and its magnitude. Results: 63 patients met inclusion criteria (38 females; 15.37±1.66 years old). >70% LSI isometric knee extension strength at 3 months showed a significant association (Table 2) and demonstrated the strongest odds of having >89% LSI on isokinetic strength tests at all 3 speeds at RTP with 180°/sec being the highest (OR=14.5; 95% CI=4.25,49.43; p= <0.001). Performance on AST showed a significant association (χ2 (1, n=63) = 17.00, p <0.001), and highest odds at 180°/sec (OR=4.61; 95% CI = 1.59, 13.39, p=<0.001) and 60°/sec (OR= 3.07; 95% CI = 1.10, 8.63, p= 0.04). Combination of performance on isometric strength tests and AST showed a significant association to isokinetic strength at all three speeds, but less predictive then isometrics in isolation. (Table 2). There was no significant relationship between YBR LSI at 3 months and isokinetic strength at 6 months. Conclusion: Standardized strength testing early in rehabilitation can help identify patients that will successfully complete RTP testing. Our results suggest that isometric knee extension strength and timed anterior stepdown test provide meaningful clinical information early in the rehabilitation process. This data also suggests that the use of YBAL for predicting isokinetic strength performance is limited. [Table: see text][Table: see text]

scholarly journals Effect of microwave disinfection on physical and mechanical properties of acrylic resins

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Acrylic Resins ◽  
Strength Tests ◽  
The Impact

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.

scholarly journals Tensile and Flexural Strength of Commercially Pure Titanium Submitted to Laser and Tungsten Inert Gas Welds

2013 ◽  
Vol 24 (6) ◽  
pp. 630-634 ◽  
Author(s):  
Juliana Abdallah Atoui ◽  
Daniela Nair Borges Felipucci ◽  
Valeria Oliveira Pagnano ◽  
Iara Augusta Orsi ◽  
Mauro Antonio de Arruda Nobilo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Laser Welding ◽  
Pure Titanium ◽  
Strength Test ◽  
Inert Gas ◽  
Commercially Pure Titanium ◽  
Middle Point ◽  
Strength Data ◽  
Commercially Pure

This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (α=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84±19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90±37.76; laser=515.85±62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations.

scholarly journals Mechanical Properties and Microstructural Features using Stone Dust as a Partial Replacement of Sand

2019 ◽  
Vol 8 (6) ◽  
pp. 5232-5237
Keyword(s):  
Mechanical Properties ◽  
Economic Growth ◽  
Sustainable Development ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Natural Resources ◽  
Strength Test ◽  
Partial Replacement ◽  
Test Results ◽  
Stone Dust

Today’s world is always leads to development in technology as well as the economic growth though sometime these will affect the environment badly. That’s why world environmental commission coined the termed called sustainable development where development takes place without hampering the others’ needs. Concrete industry is rapidly growing industry in India which consumes lots of natural resources during the production of concrete. Here Stone dust is used as a sustainable material in place of sand partially. M25 grade of concrete has been chosen for the experiments. Different mechanical properties of concrete like compressive strength, Split tensile, flexural strength etc. and Microstructural features like SEM, EDX have been included in this study. Compressive Strength and flexural strength test results shown the increase in the strength. Sulphate Resistance Properties have been tested by curing the cubes in the MgSO4 solution and increase in weight has been observed. Similarities are found in the SEM pictures

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