scholarly journals Hydrofluoric acid concentration and etching time on bond strength to lithium disilicate glass-ceramic

2021 ◽  
Vol 10 (17) ◽  
pp. e215101724776
Author(s):  
Roberta Pinto Pereira ◽  
Renan Dias Carvalho ◽  
Carolina Mayumi Cavalcanti Taguchi ◽  
Sylvio Monteiro Jr ◽  
Renata Gondo
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Bond Strength ◽  
Hydrofluoric Acid ◽  
Resin Cement ◽  
Etching Time ◽  
Post Hoc ◽  
Microshear Bond Strength ◽  
Scanning Electron

The objective of this study to evaluate the effect of different HF concentrations and etching times on the microshear bond strength (μSBS) of LD to resin cement. Forty LD sections (8x8 mm) of 3-mm thickness were randomly distributed (n=10) in accordance with the HF concentration (5 or 10%) and surface etching time (20 or 60 sec). The specimens were silanized and received an air-thinned layer of a light-curable adhesive. Six translucent tubes (0.8-mm diameter and 1-mm height) were positioned over each LD section, filled with resin cement and light-cured. After 24 h of storage, the tubes were carefully removed and the specimens were submitted to the μSBS test. The results submitted to a two-way analysis of variance and Sidak post hoc test (α=.05). Representative HF-etched specimens and one non-etched LD specimen were observed under a field-emission scanning electron microscope. The interaction between the HF concentrations and etching times was not significant (p=0.075). No significant differences were observed regarding HF concentrations and etching times (p=0.06 and p=0.059, respectively). Surfaces of specimens etched with 10% HF for 60 sec were found with grooves and microcracks. The μSBS of LD to resin cement was not significantly influenced by different HF concentrations and etching times; however, the LD surface morphology was found considerably modified.

scholarly journals The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic

2016 ◽  
Vol 27 (6) ◽  
pp. 727-733 ◽  
Author(s):  
Daniel Sundfeld ◽  
Lourenço Correr-Sobrinho ◽  
Núbia Inocêncya Pavesi Pini ◽  
Ana Rosa Costa ◽  
Renato Herman Sundfeld ◽  
...  
Keyword(s):  
Bond Strength ◽  
Glass Ceramic ◽  
Hydrofluoric Acid ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Glassy Matrix ◽  
Etching Time ◽  
Sem Images ◽  
Matrix Removal ◽  
Post Hoc

Abstract The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

scholarly journals Bonding of contemporary glass ionomer cements to different tooth substrates; microshear bond strength and scanning electron microscope study

2015 ◽  
Vol 09 (02) ◽  
pp. 176-182 ◽  
Author(s):  
Aliaa Mohamed El Wakeel ◽  
Dina Wafik Elkassas ◽  
Mai Mahmoud Yousry
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Bond Strength ◽  
Nano Particles ◽  
Glass Ionomer ◽  
Scanning Electron Microscope Study ◽  
Modes Of Failure ◽  
Occlusal Surfaces ◽  
Microshear Bond Strength ◽  
Scanning Electron

ABSTRACT Objective: This study was conducted to evaluate the microshear bond strength (μSBS) and ultramorphological characterization of glass ionomer (GI) cements; conventional GI cement (Fuji IX, CGI), resin modified GI (Fuji II LC, RMGI) and nano-ionomer (Ketac N100, NI) to enamel, dentin and cementum substrates. Materials and Methods: Forty-five lower molars were sectioned above the cemento-enamel junction. The occlusal surfaces were ground flat to obtain enamel and dentin substrates, meanwhile the cervical one-third of the root portion were utilized to evaluate the bonding efficacy to cementum substrate. Each substrate received microcylinders from the three tested materials; which were applied according to manufacturer instructions. μSBS was assessed using a universal testing machine. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey’s post-hoc test. Modes of failure were examined using stereomicroscope at ×25 magnification. Interfacial analysis of the bonded specimens was carried out using environmental field emission scanning electron microscope. Results: Two-way ANOVA revealed that materials, substrates and their interaction had a statistically significant effect on the mean μSBS values at P values; <0.0001, 0.0108 and 0.0037 respectively. RMGI showed statistically significant the highest μSBS values to all examined tooth substrates. CGI and RMGI show substrate independent bonding efficiency, meanwhile; NI showed higher μSBS values to dentin and cementum compared to enamel. Conclusion: Despite technological development of GI materials, mainly the nano-particles use, better results have not been achieved for both investigations, when compared to RMGI, independent of tooth substrate.

Etching Techniques and the Surface Morphology of the Gunflint Chert

1975 ◽  
Vol 33 ◽  
pp. 226-227
Author(s):  
A. H. Johnson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Hydrofluoric Acid ◽  
Three Dimensional ◽  
Optimum Concentration ◽  
Energy Dispersive Analysis ◽  
The Difference ◽  
Etch Time ◽  
Scanning Electron

Samples of the Gunflint Chert (2.0 billion years old), collected near Kakabeca Falls, Ontario by Dr. L. P. Knauth, have yielded several distinct and recurring morphologies when in hydrofluoric acid of varying concentrations for varying lengths of time, and viewed with a scanning electron microscope.The chert is entirely siliceous, with the exception of minor calcareous lenses identified by energy dispersive analysis. Previous studies of the Gunflint Chert have been made using TEM however SEM offers a three dimensional view which greatly aids interpretation.The samples were prepared by fracturing followed by etching in HF for 30 seconds to 48 hours with concentrations varying from .5% to 30%. It appears that the optimum concentration and etch time varies according to the particular morphology one wishes to develop. This is due to the difference in response to HF by the different textures in the rocks.

scholarly journals Additives Aid Switch to Protect the Photodegradation of Plastics in Outdoor Construction

2019 ◽  
Vol 22 (4) ◽  
pp. 277-282
Author(s):  
Salam A. Mohammed ◽  
Rahimi M. Yusop ◽  
Mohammed Abdulsattar Mohammed ◽  
Rasheed Abed Mohammed ◽  
Dina S. Ahmed ◽  
...  
Keyword(s):  
Schiff Base ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Ultraviolet Radiation ◽  
Vinyl Chloride ◽  
Leaching Test ◽  
Poly Vinyl Chloride ◽  
Effective Additive ◽  
Scanning Electron

Poly(vinyl chloride) photodecomposition films that contains melamine Schiff base (0.5% by weight) as photostabilizers upon preservation with an ultraviolet light (UV) was investigated. The photodecomposition rate constant was reduced significantly in existence of melamine Schiff base compared to PVC (blank). The Schiff base 1 was found to most effective additive in PVC photostabilization films. Photodecomposition rate content for PVC films containing Schiff base 1 was found to be 5 × 10-3 sec-1 compared to 8.7 × 10-3 sec-1 for blank film. Ultraviolet radiation aging behaviors of PVC films were studied through leaching test by measuring the degree of migration. The surface morphology of PVC films was inspected by scanning electron microscope.

Spore surface morphology of pine stem rusts of Canada as observed under a scanning electron microscope

1971 ◽  
Vol 49 (3) ◽  
pp. 371-372 ◽  
Author(s):  
Y. Hiratsuka
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Spore Surface ◽  
Endocronartium Harknessii ◽  
Scanning Electron ◽  
Shape And Size

Two types of surface markings on the aeciospores of five pine stem rusts occurring in Canada were observed under a scanning electron microscope. Spores of four species, Endocronartium harknessii (J. P. Moore) Y. Hiratsuka (= Peridermium harknessii J. P. Moore), Cronartium coleosporioides Arth. (= P. stalactiforme Arth. & Kern), C. comptoniae Arth., and C. ribicola J. C. Fisch., had annulated processes with five to seven layers and each spore had a smooth area. The smooth area was at the same level as the top layer of the processes. Each species could be distinguished by the shape and size of its processes. Spores of Cronartium comandrae Pk. had no smooth areas and had obtuse or cuspidate processes with no annulations. Different ontogenies were apparent for the two types of spore surface markings.

Small bioactive molecules as dual functional co-dopants for conducting polymers

2015 ◽  
Vol 3 (25) ◽  
pp. 5058-5069 ◽  
Author(s):  
J. A. Goding ◽  
A. D. Gilmour ◽  
P. J. Martens ◽  
L. A. Poole-Warren ◽  
R. A. Green
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Conducting Polymers ◽  
Conducting Polymer ◽  
Bioactive Molecules ◽  
Scanning Electron Microscope Image ◽  
Dual Functional ◽  
Electron Microscope Image ◽  
Scanning Electron

Scanning electron microscope image of surface morphology of conducting polymer PEDOT doped with bioactive molecules.

The Study on the Surface Morphology of Al/SnO2-Sb2O3 or SnO2-Sb2O3-MnO2/PbO2 Electrode Material

2010 ◽  
Vol 97-101 ◽  
pp. 1805-1808 ◽  
Author(s):  
Mei Cao ◽  
Zhong Cheng Guo ◽  
Xia Cui ◽  
Su Qiong He
Keyword(s):  
Thermal Decomposition ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Electroless Plating ◽  
Electrode Material ◽  
Oxide Coating ◽  
Oxide Coatings ◽  
Pbo2 Electrode ◽  
Scanning Electron

SnO2–Sb2O3 or SnO2-Sb2O3-MnO2/ PbO2 electrode on aluminum substrate were prepared by thermal decomposition、electroless plating and electrodeposition .The surface morphology of coatings were investigated by using scanning electron microscope(SEM). The results show the effects of composition of solution and thermal oxidation temperature on the microstructures of the coating were considerable. The structure of oxide coating become refined with the thermal de- composition temperature increasing. The oxide coating without Mn is coarser than those with Mn. The surface of α-PbO2 and β-PbO2 deposited on the oxide coatings without Mn prepared at 450°C are compact and even, the electrocatalyst of the electrode is optimumest.

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