scholarly journals A Chitosan–Agarose Polysaccharide-Based Hydrogel for Biomimetic Remineralization of Dental Enamel

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1137
Author(s):  
Viorica Muşat ◽  
Elena Maria Anghel ◽  
Agripina Zaharia ◽  
Irina Atkinson ◽  
Oana Cătălina Mocioiu ◽  
...  
Keyword(s):  
Tooth Enamel ◽  
Artificial Saliva ◽  
Dental Enamel ◽  
Control Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Enamel ◽  
Rod Structures ◽  
Natural Tooth ◽  
Scanning Electron

Developing multifunctional systems for the biomimetic remineralization of human enamel is a challenging task, since hydroxyapatite (HAP) rod structures of tooth enamel are difficult to replicate artificially. The paper presents the first report on the simultaneous use of chitosan (CS) and agarose (A) in a biopolymer-based hydrogel for the biomimetic remineralization of an acid-etched native enamel surface during 4–10-day immersion in artificial saliva with or without (control group) fluoride. Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, Fourier transform infrared and Raman spectroscopies, X-ray diffraction, and microhardness tests were applied to investigate the properties of the acid-etched and remineralized dental enamel layers under A and CS-A hydrogels. The results show that all biomimetic epitaxial reconstructed layers consist mostly of a similar hierarchical HAP structure to the native enamel from nano- to microscale. An analogous Ca/P ratio (1.64) to natural tooth enamel and microhardness recovery of 77.4% of the enamel-like layer are obtained by a 7-day remineralization process in artificial saliva under CS-A hydrogels. The CS component reduced carbonation and moderated the formation of HAP nanorods in addition to providing an extracellular matrix to support growing enamel-like structures. Such activity lacked in samples exposed to A-hydrogel only. These data suggest the potential of the CS-A hydrogel in guiding the formation of hard tissues as dental enamel.

Remineralization of Natural Tooth Enamel in Artificial Saliva Environment

2017 ◽  
Vol 68 (3) ◽  
pp. 510-514 ◽  
Author(s):  
Agripina Zaharia ◽  
Viorica Ghisman Plescan ◽  
Irina Atkinson ◽  
Oana Catalina Mocioiu ◽  
Alina Cantaragiu ◽  
...  
Keyword(s):  
Tooth Enamel ◽  
Artificial Saliva ◽  
Dental Enamel ◽  
Hexagonal Structure ◽  
Enamel Surface ◽  
Enamel Matrix Derivative ◽  
Phosphate Solution ◽  
X Ray ◽  
Composition And Structure ◽  
Demineralized Enamel

This paper investigates in situ remineralization of the acid-etched natural enamel surface, by incubation in a phosphate solution with neutral pH, at 37 �C for 4-10 days, without using any enamel matrix derivative (EMD). We investigated the morphology, crystallinity, chemical composition and structure of the newly grown layer onto the natural enamel surface stored in contact with artificial saliva (AS) having a composition similar to natural oral environment. The crystalline phases, crystallite size and orientation, as well as the chemical and phase composition of the remineralized dental enamel samples were studied by scanning electron microscopy coupled with energy dispersive X-ray spectrometry, Fourier transform infrared spectroscopy and X-ray diffraction. The experimental results showed that the enamel crystals grown on the demineralized enamel surface are mainly Ca-deficient apatite hexagonal structure. Fluoridated hydroxyapatite and sylvite-type KCl crystallites, which amount considerable increased in the case of sample stored in AS for 10 days, were also identified.

scholarly journals Effect of nano-hydroxyapatite modification of bamboo fiber on the properties of bamboo fiber/polylactic acid composites

BioResources ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1694-1707
Author(s):  
Kaiqiang Zhang ◽  
Jianyong Lin ◽  
Chengyi Hao ◽  
Gonghua Hong ◽  
Zhenghao Chen ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Optimum Concentration ◽  
Bamboo Fiber ◽  
Control Group ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Bamboo Fibers ◽  
Scanning Electron

An investigation was conducted of the modification of bamboo fibers (BF) by nano-hydroxyapatite (N-HA) and its impact on the mechanical and thermal properties of BF/PLA composites. The functional groups, and crystallinity of the N-HA modified BF were investigated with Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), respectively. The effects of different N-HA contents on the properties of the BF/PLA composites were evaluated using mechanical testing (bending, tensile, and impact properties), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that the most suitable N-HA content was 7.5 wt.%. Treating BF with an optimum concentration of N-HA decreased the polarity of the bamboo fiber, while maintaining the crystal structure of the cellulose. Compared with the control group, the mechanical properties and the crystallinity of the modified BF/PLA composites were improved, and the flexural, tensile, and impact strengths increased by 10.2%, 11.6%, and 28.1%, respectively. The thermogravimetric analysis results indicated modified BF/PLA composites has higher thermal stability.

Regeneration of Tooth Enamel by Flexible Hydroxyapatite Sheet

2011 ◽  
Vol 493-494 ◽  
pp. 615-619 ◽  
Author(s):  
Shigeki Hontsu ◽  
Nobuhiro Kato ◽  
Ei Yamamoto ◽  
Hiroaki Nishikawa ◽  
Masanobu Kusunoki ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Tooth Enamel ◽  
Dental Enamel ◽  
Laser Deposition ◽  
Phosphate Solution ◽  
X Ray Diffraction ◽  
Human Teeth ◽  
X Ray ◽  
Scratch Tests ◽  
Soluble Substrate

Before a tooth erupts, the ameloblasts are lost, which means that the tooth enamel does not regenerate itself after tooth eruption. In the present study, we attempt to regenerate the tooth enamel artificially using a flexible hydroxyapatite (HAp) sheet. First, a HAp film was deposited on a soluble substrate by pulsed laser deposition (PLD) using an ArF excimer laser. Next, the HAp film was collected as a freestanding sheet by dissolving the substrate using a solvent. The HAp sheet was adhered to the extracted human teeth using a calcium phosphate solution. The variation of the crystal structure of the HAp sheet with time was investigated by X-ray diffraction analysis. Furthermore, the variation in the mechanical characteristics with time between the HAp sheet and dental enamel were evaluated using tensile and scratch tests. The results suggest that the HAp sheet became fused to the tooth enamel within approximately one week.

scholarly journals Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology

2004 ◽  
Vol 18 (4) ◽  
pp. 306-311 ◽  
Author(s):  
Cristiane Franco Pinto ◽  
Rogério de Oliveira ◽  
Vanessa Cavalli ◽  
Marcelo Giannini
Keyword(s):  
Surface Roughness ◽  
Artificial Saliva ◽  
Dental Enamel ◽  
Enamel Surface ◽  
Control Group ◽  
Third Molars ◽  
Carbamide Peroxide ◽  
Peroxide Bleaching ◽  
Human Enamel ◽  
Microhardness Testing

The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment). Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11): control, Whiteness Perfect - 10% carbamide peroxide (10% CP), Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP), Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - 35% HP. Bleaching agents were applied according to manufacturers' instructions. The control group remained not treated and stored in artificial saliva. Microhardness testing was performed with a Knoop indentor and surface roughness was analyzed with a profilometer. Morphologic observations were carried out with scanning electron microscopy (SEM). Results were statistically analyzed by two-way analysis of variance and Tukey's test (5%), and revealed a significant decrease in microhardness values and a significant increase in surface roughness post-bleaching. Changes in enamel morphology after bleaching were observed under SEM. It was concluded that bleaching agents can alter the microhardness, roughness and morphology of dental enamel surface.

Energy Dispersive X-Ray Spectroscopy Evaluation of Demineralized Human Enamel after Titanium Tetrafluoride Application

2015 ◽  
Vol 39 (2) ◽  
pp. 124-127 ◽  
Author(s):  
PCC Alcântara ◽  
AK Alexandria ◽  
IPR Souza ◽  
LC Maia
Keyword(s):  
Titanium Dioxide ◽  
Tooth Enamel ◽  
Permanent Tooth ◽  
Energy Dispersive ◽  
Control Group ◽  
Third Molars ◽  
Titanium Tetrafluoride ◽  
X Ray ◽  
Human Enamel ◽  
Experimental Group

Objective: Evaluate the presence of a titanium dioxide layer after application of titanium tetrafluoride on human permanent tooth enamel. Study design: The sample consisted of unerupted third molars. After the removal of the roots, each tooth was mesiodistally divided into 2 fragments, one reserved for the experimental group and the other for the control group. Before the treatments the fragments were artificially demineralized. The experimental group (n=5) received an application of 4% titanium tetrafluoride, for one minute and the control group (n=5) did not receive any treatment. The samples were sputter-coated with a 20-30nm gold layer as the energy dispersive x-ray spectrometer analysis was carried out in a scanning electron microscope and the results were descriptively analyzed. Results: The titanium dioxide layer was present on all experimental samples with a titanium peak varying between 6.82 and 26.37%. This layer was not found in the control group. Fluoride and calcium fluoride precipitates were present in the samples treated with titanium tetrafluoride. Conclusion: Titanium dioxide layer was formed after one titanium tetrafluoride application, but it was not uniform. Further studies should be carried out so that both the morphology and thickness of such layers can be better understood.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

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