scholarly journals Evaluation of morphological and chemical alterations in enamel, dentin and cementum after internal bleaching technique using different bleaching agents

2016 ◽  
Vol 19 (4) ◽  
pp. 56
Author(s):  
Nadia De Souza Ferreira ◽  
Paula Elaine Cardoso ◽  
Natalia Passos Ferreira ◽  
Amanda Costa Corocher ◽  
Isabela Ferreira Paulino ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Tooth Bleaching ◽  
Sodium Perborate ◽  
Carbamide Peroxide ◽  
Organic Part ◽  
Calcium Phosphorus ◽  
And Control ◽  
Scanning Electron

<p><strong>Objective</strong>: The aim of this study was to evaluate the morphological and chemical alterations in enamel, dentin and cementum after internal bleaching using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). <strong>Material and Methods:</strong> Seventy-two bovine incisor teeth were prepared, cut and bleached for 7 days as follows: HP: 35% hydrogen peroxide gel; HP+SP: 35% hydrogen peroxide gel + sodium perborate; CP: 37% carbamide peroxide gel; CP+SP: 37% carbamide peroxide gel + sodium perborate; SP: sodium perborate + water; and control: deionized water. The specimens were sectioned and prepared for morphological analysis under SEM and analysis of calcium, phosphorus, oxygen and carbon levels using EDS. <strong>Results</strong>: A significant reduction was found in the calcium levels in enamel after treatment with CP + SP and CP (p &lt; 0.05). Carbon (organic part) was hardly altered in enamel. A significant reduction in the calcium levels was found in dentin in Groups HP+SP, CP and CP+SP. Phosphorus levels increased after SP+H20 (p &lt; 0.05) and CP (p &lt; 0.05). Carbon levels showed little variation and the largest amount was found in Groups CP and CP+SP (p &lt; 0.05); in the other groups there was no alteration. A significant reduction in the calcium levels was found in the cementum in Group CP+SP (p &lt; 0.05). <strong>Conclusion</strong>: Alterations in the enamel, dentin and cementum compositions occurred after bleaching and these alterations showed to be less significant with sodium perborate and water.</p><p><strong>Keywords</strong>: Carbamide peroxide; Hydrogen peroxide; Scanning electron microscopy; Sodium perborate; Tooth bleaching.</p>

scholarly journals Evaluation of the bleached human enamel by Scanning Electron Microscopy

2005 ◽  
Vol 13 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Carolina Baptista Miranda ◽  
Clovis Pagani ◽  
Ana Raquel Benetti ◽  
Fábio da Silva Matuda
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Enamel Surface ◽  
Halogen Lamp ◽  
Carbamide Peroxide ◽  
Total Exposure ◽  
Human Enamel ◽  
Dental Hard Tissues ◽  
Scanning Electron

Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted in this study followed the application protocols advised by manufacturers. Evaluation of groups submitted to 35% carbamide peroxide was carried out after two time intervals (30 minutes and 2 hours per session), following the extreme situations recommended by the manufacturer. Specimens were prepared for SEM analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were characteristic of an erosive process that took place on human enamel. Depression areas, including the formation of craters, and exposure of enamel rods could also be detected. Conclusion: Bleaching effects on enamel morphology were randomly distributed throughout enamel surface and various degrees of enamel damage could be noticed. Clinical significance: In-office bleaching materials may adversely affect enamel morphology and therefore should be used with caution.

scholarly journals Influence of Hydroxyapatite Nanospheres in Dentin Adhesive on the Dentin Bond Integrity and Degree of Conversion: A Scanning Electron Microscopy (SEM), Raman, Fourier Transform-Infrared (FTIR), and Microtensile Study

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2948
Author(s):  
Rana S Al-Hamdan ◽  
Basil Almutairi ◽  
Hiba F Kattan ◽  
Noura A. Alsuwailem ◽  
Imran Farooq ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Study Groups ◽  
Degree Of Conversion ◽  
Hybrid Layer ◽  
X Ray ◽  
And Control ◽  
Scanning Electron

An experimental adhesive incorporated with different nano-hydroxyapatite (n-HA) particle concentrations was synthesized and analyzed for dentin interaction, micro-tensile bond strength (μTBS), and degree of conversion (DC). n-HA powder (5 wt % and 10 wt %) were added in adhesive to yield three groups; gp-1: control experimental adhesive (CEA, 0 wt % HA), gp-2: 5 wt % n-HA (HAA-5%), and gp-3: 10 wt % n-HA (HAA-10%). The morphology of n-HA spheres was evaluated using Scanning Electron Microscopy (SEM). Their interaction in the adhesives was identified with SEM, Energy-Dispersive X-ray (EDX), and Micro-Raman spectroscopy. Teeth were sectioned, divided in study groups, and assessed for μTBS and failure mode. Employing Fourier Transform-Infrared (FTIR) spectroscopy, the DC of the adhesives was assessed. EDX mapping revealed the occurrence of oxygen, calcium, and phosphorus in the HAA-5% and HAA-10% groups. HAA-5% had the greatest μTBS values followed by HAA-10%. The presence of apatite was shown by FTIR spectra and Micro-Raman demonstrated phosphate and carbonate groups for n-HA spheres. The highest DC was observed for the CEA group followed by HAA-5%. n-HA spheres exhibited dentin interaction and formed a hybrid layer with resin tags. HAA-5% demonstrated superior μTBS compared with HAA-10% and control adhesive. The DC for HAA-5% was comparable to control adhesive.

Colonization of Cecal Mucosal Epithelium in Chicks Treated with a Continuous Flow Culture of 29 Characterized Bacteria: Confirmation by Scanning Electron Microscopy†

1995 ◽  
Vol 58 (8) ◽  
pp. 837-842 ◽  
Author(s):  
R. E. DROLESKEY ◽  
D. E. CORRIER ◽  
D. J. NISBET ◽  
J. R. DELOACH
Keyword(s):  
Electron Microscopy ◽  
Fatty Acids ◽  
Scanning Electron Microscopy ◽  
Salmonella Typhimurium ◽  
Continuous Flow ◽  
Volatile Fatty Acids ◽  
Bacterial Colonization ◽  
Mucosal Epithelium ◽  
And Control ◽  
Scanning Electron

Bacterial colonization of cecal mucosal epithelium in 3-day-old chicks administered a characterized continuous-flow (CF) culture of 29 microorganisms on the day of hatch was evaluated by scanning electron microscopy. Extensive colonization of the mucosa was noted in the ceca of CF-treated chicks, with large colonies of bacteria located predominately within and between crypts. Cecal crypts from control chicks contained only thin strands of mucus with a few bacteria. Individual cells and clumps of bacteria were observed bound to the mucosal epithelium in both CF-treated and control chicks. Colonization by CF culture bacteria was accompanied by an increase in the concentration of volatile fatty acids in the cecal contents and increased resistance to colonization by Salmonella typhimurium.

Effects of Impaired Fibrinopeptide A Cleavage on Fibrin Clot Structure: Studies with an Aα R16C Dysfibrinogen.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1617-1617
Author(s):  
Veronica H. Flood ◽  
Chandrasekaran Nagaswami ◽  
Irina N. Chernysh ◽  
Hamid A. Al-Mondhiry ◽  
John W. Weisel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Normal Control ◽  
Fibrin Clot ◽  
Fiber Formation ◽  
Protein Sequencing ◽  
Fibrinopeptide A ◽  
And Control ◽  
Clot Structure ◽  
Scanning Electron

Abstract Cleavage of fibrinopeptide A is the first step in fibrin clot formation, and mutations at the fibrinopeptide A cleavage site are the most common cause of dysfibrinogenemia. We describe here the effect on clot structure of a mutant Aα R16C fibrinogen with defective fibrinopeptide A cleavage (designated fibrinogen Hershey III). The propositus, a young child with mild bleeding symptoms, was found to be heterozygous for the Aα R16C mutation. Fibrinogen was purified from Hershey III and control plasma via glycine precipitation. Hershey III fibrinogen was only 63 ± 10% clottable with thrombin (mean ± SEM), as compared to 96 ± 0.4% for normal fibrinogen. Since the propositus was heterozygous for the mutation, the unclottable portion likely consisted of mutant homodimers, but it was still possible that normal/mutant heterodimers existed. Because the cysteine in the mutant fibrinogen prevents thrombin-mediated fibrinopeptide A cleavage, we hypothesized that incorporation of uncleaved fibrinopeptide A, if present, would affect clot structure. Western blotting was used to evaluate the presence of fibrinopeptide A in clottable and unclottable fibrinogen. For fibrinogen Hershey III, both forms showed a substantial amount of fibrinopeptide A, suggesting that mutant fibrinogen was incorporated into the final clot. No fibrinopeptide A was seen in either the clottable or unclottable fibrinogen from the normal control. Next, fibrin clots were made with thrombin, critical-point dried, and visualized via scanning electron microscopy. Visco-elastic measurements were obtained with a torsion pendulum and clot permeability was compared to that of clots formed with normal fibrinogen. The relative proportions of normal vs. mutant fibrinogen in the clottable and unclottable fibrinogen were assessed by protein sequencing. Scanning electron microscopy showed that the Hershey III clots displayed abnormal architecture with many short fibrin fibrils, consistent with premature fibril termination. Hershey III clots also had thicker fibers, with an average fiber diameter of 182 nm compared to 151 nm for the normal control. A significant difference in clot stiffness (G′), energy dissipated by viscous processes (G″), and permeability (Ks) was seen when fibrinogen Hershey III was compared to a normal control (see table). Protein sequencing of the unclottable Hershey III fibrinogen showed only the homozygous mutant form, while the fibrin clot showed approximately 50% each of the wild-type and mutant fibrinogen chains. These results support the presence of both homodimers and heterodimers in fibrinogen Hershey III, and suggest that incorporation of Aα R16C heterodimers into the fibrin clot leads to defects in fiber formation and clot structure. Mechanical Properties of Hershey III and Control Clots Hershey III Control P G′ (dyne/cm2) 10.8 37.9 0.03 G″ (dyne/cm2) 0.83 2.77 0.04 Tan δ (G″/G′) 0.077 0.076 0.79 Ks (10−7 cm2) 1.86 2.44 0.01

Preparing Diatoms for EM

2000 ◽  
Vol 8 (9) ◽  
pp. 36-37
Author(s):  
Greg Strout
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Diatomaceous Earth ◽  
Potassium Dichromate ◽  
Scanning Electron

Diatoms make for beautiful specimens for both transmission and scanning electron microscopy. As well, they are studied by many people, and there is always a need for good diatom preparations for EM.I find that the diatoms in diatomaceous earth are usually broken, and like to prepare my own from fresh specimens. The materials needed for this are a plankton net, some potassium dichromate, and 30% hydrogen peroxide. Once the diatoms are collected (plankton net tows from shoreline, or wherever), they can be cleaned using the chemicals.

scholarly journals Evaluation of enamel by scanning electron microscopy green LED associated to hydrogen peroxide 35% for dental bleaching

2014 ◽  
Author(s):  
Juliana S. C. Monteiro ◽  
Susana C. P. S. de Oliveira ◽  
Fátima A. A. Zanin ◽  
Gustavo M. P. Santos ◽  
Fernando J. P. Sampaio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Dental Bleaching ◽  
Green Led ◽  
Scanning Electron

scholarly journals An in situ evaluation of Bioactives on the morphology of bleached Enamel

2016 ◽  
Vol 17 (3) ◽  
pp. 192-197
Author(s):  
Yasmin do Socorro Batista de Lima Gomes ◽  
Larissa Dias Alexandrino ◽  
Cecy Martins Silva ◽  
Thiago da Rosa Nogueira ◽  
Cristiane de Melo Alencar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Third Molars ◽  
Double Blind ◽  
Human Morphology ◽  
Before And After ◽  
Post Hoc ◽  
Scanning Electron

ABSTRACT Aim The aim of this study was to use surface rugosity analysis (Ra) and scanning electron microscopy (SEM) comparing effects of nano-hydroxyapatite (NANO), casein phosphopeptideamorphous calcium phosphate (CPP-ACP), and NovaMin (NOVA) on enamel's human morphology bleached with 37.5% hydrogen peroxide. Materials and methods Forty specimens (3 × 3 × 3 mm) were obtained from fully included third molars and four specimens were attached in the first molars of the volunteers. The POLApositive control has only been bleached. Three experimental groups were bleached and treated with respective bioactive: NANO, CPP-ACP, and NovaMin. The Ra analyses were performed before and after the treatment using a rugosimeter. The obtained photomicrographs were analyzed using SEM (n = 3) by three examiners, and the study was double blind. Results The Ra results were analyzed by one-way analysis of variance and Tukey's post hoc test (p < 0.05). All experimental groups showed significant differences of the others; however, the experimental groups were not significantly different from each other. Conclusion The enamel morphology of the bioactive-treated groups had more regular surfaces, than the others. How to cite this article da Rosa Nogueira T, Alexandrino LD, de Lima Gomes YSB, de Melo Alencar C, Alves EB, Silva CM. An in situ evaluation of Bioactives on the morphology of bleached Enamel. J Contemp Dent Pract 2016;17(3):192-197.

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