scholarly journals Evaluation of low-fusing ceramic systems combined with titanium grades II and V by bending test and scanning electron microscopy

2003 ◽  
Vol 11 (4) ◽  
pp. 354-360 ◽  
Author(s):  
Wilson José Garbelini ◽  
Guilherme Elias Pessanha Henriques ◽  
Manoel Troia Junior ◽  
Marcelo Ferraz Mesquita ◽  
Cássia Cilene Dezan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bond Strength ◽  
Bending Strength ◽  
Bending Test ◽  
Control Group ◽  
Three Point Bending ◽  
Grade Ii ◽  
Titanium Grade ◽  
Scanning Electron

The bond strength by three point bending strength of two metal substrates (commercially pure titanium or grade II, and Ti-6Al-4V alloy or grade V) combined to three distinct low-fusing ceramic systems (LFC) and the nature of porcelain-metal fracture by scanning electron microscopy (SEM) were evaluated. The results were compared to a combination of palladium-silver (Pd-Ag) alloy and conventional porcelain (Duceram VMK68). Sixty metal strips measuring 25x3x0.5mm were made - 30 of titanium grade II and 30 of titanium grade V, with application of the following types of porcelain: Vita Titankeramik, Triceram or Duceratin (10 specimens for each porcelain). The porcelains were bonded to the strips with dimensions limited to 8x3x1mm. The control group consisted of ten specimens Pd-Ag alloy/Duceram VMK68 porcelain. Statistical analyses were made by one-way analysis of variance (ANOVA) and Tukey test at 5% significance level. Results showed that the bond strength in control group (48.0MPa ± 4.0) was significantly higher than the Ti grade II (26.7MPa ± 4.1) and Ti grade V (25.2MPa ± 2.2) combinations. When Duceratin porcelain was applied in both substrates, Ti grade II and Ti grade V, the results were significantly lower than in Ti grade II/Vitatitankeramik. SEM analysis indicated a predominance of adhesive fractures for the groups Ti grade II and Ti grade V, and cohesive fracture for control group Pd-Ag/Duceram. Control group showed the best bond strength compared to the groups that employed LFC. Among LFC, the worst results were obtained when Duceratin porcelain was used in both substrates. SEM confirmed the results of three point bending strength.

Effects of Delta - Ferrite Content on the Integrity of Reactor Vessel Cladding

2010 ◽  
Author(s):  
Ho-Sang Shin ◽  
Jin-Ki Hong ◽  
Koo-Kab Chung ◽  
Hae-Dong Chung ◽  
Gwang-Yil Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Reactor Vessel ◽  
Bending Test ◽  
Ferrite Content ◽  
Delta Ferrite ◽  
Bending Tests ◽  
Asme Code ◽  
Two Phases ◽  
Scanning Electron

As the design life of new nuclear power plant increases, the austenitic stainless cladding integrity of reactor vessel becomes one of the new concerns. Since 1970’s, there have been some specific recommendations on delta ferrite content of austenitic cladding of reactor vessels and welds. It has been known that the delta ferrite is beneficial for reducing micro-fissure in welds, though the high delta ferrite content increases the probability of embrittlment of welds. In this study, the mechanical and microstructural properties of austenitic weld metals with the limit values of the recommended range (5 ∼ 18 FN) of the delta ferrite control on low alloy steels were characterized by using bending test and scanning electron microscopy. The base metal was ASME Code Sec. II specification SA 508 Gr. 3 Cl. 1 plate and weld materials were EQ308L and EQ309L strips. Four kinds of cladding were deposited with submerged arc welding process on SA508 cl.3 plates. The bending tests were performed through ASME code Sec. IX and the microstructure of fractured surfaces was analyzed by scanning electron microscopy (SEM). In bending tests, there were no fractures except the highest delta ferrite content specimens (28FN). From the SEM observation of fractured surfaces, cracks initiated from the interface between austenite and ferrites phases in the cladding layer and propagated through the continuous interfaces between two phases. For specimens without continuous interfaces of two phases, though the cracks were observed in the interface of phases, the propagation of cracks was not observed. From the test results, continuous interfaces between austenite matrix and ferrite phase provide the path for crack propagation. And the delta ferrite content affects the integrity of cladding of reactor vessel.

scholarly journals Effects of Dentifrices Containing Nanohydroxyapatite on Dentinal Tubule Occlusion—A Scanning Electron Microscopy and EDX Study

2020 ◽  
Vol 10 (18) ◽  
pp. 6513
Author(s):  
Emilia Bologa ◽  
Simona Stoleriu ◽  
Gianina Iovan ◽  
Cristina Angela Ghiorghe ◽  
Irina Nica ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Study Groups ◽  
Control Group ◽  
Dentinal Tubule ◽  
Human Teeth ◽  
Dentinal Tubules ◽  
Mineral Deposition ◽  
Tubule Occlusion ◽  
Scanning Electron

This in vitro study evaluated the effects of dentifrices containing nano-hydroxyapatite (n-HAp) on dentinal tubule occlusion and on mineral deposition. Dentin specimens of ten human teeth were submersed for 30 s in 40% citric acid and then randomly divided into four groups (three study groups and one control group). In the study groups, the dentin samples were exposed to three different n-HAp toothpastes: Karex (Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, Germany), Biorepair Plus Sensitive (Coswell SpA, Bologna, Italy), and Dr. Wolff’s Biorepair (Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, Germany); in the control group no toothpaste was applied. All of the samples were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. In the control group all of the samples showed a frank and wide opening of the dentinal tubules, whereas in the study groups different degrees of tubule closure by mineral depositions were observed. Toothpastes containing n-HAp determined a significant occlusion of dentinal tubules and a significant increase of mineral deposition on the dentin surface. All three tested toothpastes showed similar results regarding the degree of dentinal tubule closure. Varying degrees of differences in calcium, phosphate, carbon, and oxygen ion concentrations among the three tested toothpastes were obtained.

scholarly journals In VitroAdherence of Oral Bacteria to Different Types of Tongue Piercings

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Pereira Borges ◽  
Julio Cesar Campos Ferreira-Filho ◽  
Julia Medeiros Martins ◽  
Caroline Vieira Alves ◽  
Bianca Marques Santiago ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Oral Bacteria ◽  
The Other ◽  
Control Group ◽  
Colony Forming Units ◽  
Different Types ◽  
Scanning Electron

The purpose of this work was to verifyin vitroadherence ofE. corrodensandS. oralisto the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (pvalue<0.05). ForE. corrodens, difference among types of material was observed (p<0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence ofS. oralisdiffered among piercings, showing lower colonization (p<0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization byE. corrodensandS. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

scholarly journals Gastroduodenal Morphology and Related Symptoms in Chronic Alcoholics

1997 ◽  
Vol 4 (1) ◽  
pp. 29-33 ◽  
Author(s):  
T. Hauge ◽  
J. Persson ◽  
Å. Nilsson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gastrointestinal Endoscopy ◽  
Gastrointestinal Symptoms ◽  
Control Group ◽  
Upper Gastrointestinal Endoscopy ◽  
Alcohol Group ◽  
Group 12 ◽  
Upper Gastrointestinal ◽  
Scanning Electron

Twenty-four chronic alcoholics admitted to hospital for detoxification after a drinking spree were examined by upper gastrointestinal endoscopy. Biopsy specimens were taken from corpus/fundus, antrum and duodenum for tissue histology (eosin stain). From the duodenum villus index and ultrastructure (scanning electron microscopy, SEM) were also performed. As a control group 12 subjectively healthy non-alcoholics referred to upper gastrointestinal endoscopy mainly for dyspepsia were chosen.Gastrointestinal symptoms were common in alcoholics (88%). Endoscopic and histological gastroduodenitis were not more common in the alcohol group. There was no correlation between gastrointestinal symptoms and endoscopic or histological gastroduodenitis in both groups. In the duodenum, 50% of the alcoholics and 82% in the control group had alterations by scanning electron microscopy. Ten of the 11 alcoholics with an abnormal ultrastructure had diarrhoea. In the control group dyspepsia (ulcus suspect) was correlated to a pathological SEM.

Differential Resin-Dentin Bonds Created after Caries Removal with Polymer Burs

2012 ◽  
Vol 18 (3) ◽  
pp. 497-508 ◽  
Author(s):  
Manuel Toledano ◽  
Inmaculada Cabello ◽  
Monica Yamauti ◽  
Raquel Osorio
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bond Strength ◽  
Measured Data ◽  
Glass Ionomer ◽  
Single Bond ◽  
Microtensile Bond Strength ◽  
Caries Removal ◽  
Thick Smear ◽  
Scanning Electron

AbstractThe objective of this article was to investigate the effect of carbide and polymer burs caries removal methods on the bond strength of different adhesives to dentin. Resin restorations were performed in sound and caries-affected dentin, after using polymer or carbide burs and bonding with four different adhesive (Single bond, SB; Clearfil SE bond, SEB; FL-Bond II, FLB; and Fuji II-LC, FUJI). Microtensile bond strength (MTBS) was measured. Data were analyzed with ANOVA and Student-Newman-Keuls tests. Debonded surfaces were observed by scanning electron microscopy. Bonded interfaces were examined using light microscopy (Masson's trichrome staining). In sound dentin, MTBS was similar for SEB and SB, and higher than that of FLB and FUJI. Bond strength to carbide bur prepared dentin was similar for SB, SEB, and FLB; FUJI presented the lowest. SB applied on polymer bur excavated dentin presented similar values to those of the carbide bur group; MTBS attained by SEB, FLB, and FUJI decreased when bonding to dentin treated with polymer burs; FUJI yielded pretesting failures in all specimens. Polymer burs created a thick smear layer that was not infiltrated by tested self-etching agents. The bonding effectiveness of self-etching and glass-ionomer-like adhesives to dentin decreased when polymer burs were used.

scholarly journals Reparability of Aged Silorane With Methacrylate-Based Resin Composite: Micro-Shear Bond Strength and Scanning Electron Microscopy Evaluation

2012 ◽  
Vol 37 (1) ◽  
pp. 28-36 ◽  
Author(s):  
L Giachetti ◽  
D Scaminaci Russo ◽  
M Baldini ◽  
C Goracci ◽  
M Ferrari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bond Strength ◽  
Intermediate Layer ◽  
Clinical Relevance ◽  
Shear Bond Strength ◽  
Resin Composite ◽  
Composite Restorations ◽  
Scanning Electron Microscopy Evaluation ◽  
Scanning Electron

Clinical Relevance Aged silorane composite restorations can be repaired with a methacrylate-based resin composite by using a phosphate-methacrylate–based adhesive as the intermediate layer.

Mechanical Characterizations of Saxidomus purpuratus Shells

2010 ◽  
Vol 434-435 ◽  
pp. 601-604 ◽  
Author(s):  
W. Yang ◽  
Y. Jiang ◽  
G.P. Zhang ◽  
Y.S. Chao ◽  
Xiao Wu Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Bending Strength ◽  
Target Material ◽  
Organic Matrix ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Saxidomus Purpuratus ◽  
Scanning Electron

A sort of biological shells (Saxidomus purpuratus), which belongs to Bivalve, was selected as the target material, and hardness and dynamic three point bending fatigue tests were conducted to examine its mechanical properties. Microhardness measurements showed that the inner layer is the hardest. The indentation on the specimen with a lower bending strength was damaged more seriously by the same load. Three point bending fatigue tests demonstrated that this kind of the shells with a special structure comprising mineral and organic matrix can experience the repeated loads instead of immediate breaking. The fatigue results on a single shell investigated here indicated that the fatigue strength is usually less than the static bending strength. Most of the fatigue lives of the specimens are less than 2105 cycles. In addition, fatigue fracture surfaces are observed by scanning electron microscopy.

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