Standard Versus Real Versus Fake Braces: Design And Microstructure Comparison

Introduction: The growing demand for orthodontic braces among Malaysian community has led to the development of "fake" and "real" braces. "Fake" braces refer to braces that are worn as costume and are not bonded to teeth hence unable to produce movement of teeth. "Real" braces refer to braces that are bonded to tooth structure and are able to produce tooth movement. The braces are bonded by unqualified practitioners with no formal dental education and they provide braces treatment in unlicensed premises such as hotel rooms or patients' own homes. Materials and Methods: This study was conducted to investigate the design and microstructure of several types of "fake", "real" and standard braces. A total of 9 upper right central incisor brackets were scanned using high resolution scanning electron microscopy (SEM) with magnifications of 65x, 500x and 1000x. Brackets slot heights and depths were also measured to compare slot dimensions between "fake", "real" and standard braces. Results: The surface textures of "fake" and "real" braces were noticeably more granular and unpolished as compared to conventional brackets. Furthermore, all "fake" and some "real" braces upper right central incisor bracket designs were distinctly different from the standard braces. The slot dimensions of "fake" and "real" braces were also significantly larger that standard braces. Conclusion(s): In conclusion, the surface texture and morphology of "fake" and "real" braces were crude and different when compared to conventional brackets.

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Examination of Schistosome Cercariae and Schistosomules by Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062154 ◽

1969 ◽

Vol 27 ◽

pp. 50-51

Author(s):

D. Johnson ◽

P. Moriearty

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Light Microscopy ◽

Surface Structure ◽

Extensive Study ◽

Scanning Microscopy ◽

Host Parasite ◽

Conventional Electron Microscopy ◽

Scanning Electron

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.

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High Resolution Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086696 ◽

1991 ◽

Vol 49 ◽

pp. 478-479

Author(s):

David Joy ◽

James Pawley

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Electron Beam ◽

Electron Microscope ◽

High Resolution ◽

Scanning Electron Microscope ◽

Electron Probe ◽

Impact Point ◽

Interaction Volume ◽

Scanning Electron

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

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Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139834 ◽

1995 ◽

Vol 53 ◽

pp. 692-693

Author(s):

Yun Lu ◽

David C. Joy

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Morphological Development ◽

Early Hydration ◽

X Ray ◽

Blended Cements ◽

Powder Particles ◽

Chemical Wastes ◽

Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

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Progress in high-resolution CRYO-SEM imaging of viral particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166555 ◽

1996 ◽

Vol 54 ◽

pp. 818-819

Author(s):

Ya Chen ◽

Geoffrey Letchworth ◽

John White

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Structural Information ◽

Signal To Noise Ratio ◽

Flexible Structures ◽

Simian Virus ◽

Topographic Features ◽

Viral Particles ◽

Scanning Electron

Low-temperature high-resolution scanning electron microscopy (cryo-HRSEM) has been successfully utilized to image biological macromolecular complexes at nanometer resolution. Recently, imaging of individual viral particles such as reovirus using cryo-HRSEM or simian virus (SIV) using HRSEM, HV-STEM and AFM have been reported. Although conventional electron microscopy (e.g., negative staining, replica, embedding and section), or cryo-TEM technique are widely used in studying of the architectures of viral particles, scanning electron microscopy presents two major advantages. First, secondary electron signal of SEM represents mostly surface topographic features. The topographic details of a biological assembly can be viewed directly and will not be obscured by signals from the opposite surface or from internal structures. Second, SEM may produce high contrast and signal-to-noise ratio images. As a result of this important feature, it is capable of visualizing not only individual virus particles, but also asymmetric or flexible structures. The 2-3 nm resolution obtained using high resolution cryo-SEM made it possible to provide useful surface structural information of macromolecule complexes within cells and tissues. In this study, cryo-HRSEM is utilized to visualize the distribution of glycoproteins of a herpesvirus.

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Imaging of polymer single crystals in low-voltage, high-resolution scanning electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178665 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1106-1107

Author(s):

W.W. Adams ◽

G. Price ◽

A. Krause

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Single Crystals ◽

Low Voltage ◽

Polymer Surface ◽

Beam Current ◽

Image Features ◽

First Results ◽

Scanning Electron

It has been shown that there are numerous advantages in imaging both coated and uncoated polymers in scanning electron microscopy (SEM) at low voltages (LV) from 0.5 to 2.0 keV compared to imaging at conventional voltages of 10 to 20 keV. The disadvantages of LVSEM of degraded resolution and decreased beam current have been overcome with the new generation of field emission gun SEMs. In imaging metal coated polymers in LVSEM beam damage is reduced, contrast is improved, and charging from irregularly shaped features (which may be unevenly coated) is reduced or eliminated. Imaging uncoated polymers in LVSEM allows direct observation of the surface with little or no charging and with no alterations of surface features from the metal coating process required for higher voltage imaging. This is particularly important for high resolution (HR) studies of polymers where it is desired to image features 1 to 10 nm in size. Metal sputter coating techniques produce a 10 - 20 nm film that has its own texture which can obscure topographical features of the original polymer surface. In examining thin, uncoated insulating samples on a conducting substrate at low voltages the effect of sample-beam interactions on image formation and resolution will differ significantly from the effect at higher accelerating voltages. We discuss here sample-beam interactions in single crystals on conducting substrates at low voltages and also present the first results on HRSEM of single crystal morphologies which show some of these effects.

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High-Resolution Resistance Mapping in SEM

10.31399/asm.cp.istfa2018p0353 ◽

2018 ◽

Author(s):

Grigore Moldovan ◽

Wolfgang Joachimi ◽

Guillaume Boetsch ◽

Jörg Jatzkowski ◽

Frank Altman

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Reference Structure ◽

Total Resistance ◽

Embedded Electronics ◽

Improved Performance ◽

Mapping Techniques ◽

Scanning Electron

Abstract This work presents advanced resistance mapping techniques based on Scanning Electron Microscopy (SEM) with nanoprobing systems and the related embedded electronics. Focus is placed on recent advances to reduce noise and increase speed, such as integration of dedicated in situ electronics into the nanoprobing platform, as well as an important transition from current-sensitive to voltagesensitive amplification. We show that it is now possible to record resistance maps with a resistance sensitivity in the 10W range, even when the total resistance of the mapped structures is in the range of 100W. A reference structure is used to illustrate the improved performance, and a lowresistance failure case is presented as an example of analysis made possible by these developments.

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