scholarly journals Dental abrasion as a cutting process

2016 ◽  
Vol 6 (3) ◽  
pp. 20160008 ◽  
Author(s):  
Peter W. Lucas ◽  
Mark Wagner ◽  
Khaled Al-Fadhalah ◽  
Abdulwahab S. Almusallam ◽  
Shaji Michael ◽  
...  
Keyword(s):  
Tooth Surface ◽  
Wear Particles ◽  
Polyphenolic Compound ◽  
Physiological Mechanisms ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tooth Tissue ◽  
Very High ◽  
Over Time ◽  
Theoretical Developments

A mammalian tooth is abraded when a sliding contact between a particle and the tooth surface leads to an immediate loss of tooth tissue. Over time, these contacts can lead to wear serious enough to impair the oral processing of food. Both anatomical and physiological mechanisms have evolved in mammals to try to prevent wear, indicating its evolutionary importance, but it is still an established survival threat. Here we consider that many wear marks result from a cutting action whereby the contacting tip(s) of such wear particles acts akin to a tool tip. Recent theoretical developments show that it is possible to estimate the toughness of abraded materials via cutting tests. Here, we report experiments intended to establish the wear resistance of enamel in terms of its toughness and how friction varies. Imaging via atomic force microscopy (AFM) was used to assess the damage involved. Damage ranged from pure plastic deformation to fracture with and without lateral microcracks. Grooves cut with a Berkovich diamond were the most consistent, suggesting that the toughness of enamel in cutting is 244 J m −2 , which is very high. Friction was higher in the presence of a polyphenolic compound, indicating that this could increase wear potential.

Development of the UHV-STM

1990 ◽  
Vol 48 (1) ◽  
pp. 322-323
Author(s):  
M. Iwatsuki ◽  
S. Kitamura ◽  
A. Mogami
Keyword(s):  
Surface Science ◽  
Real Space ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Great Promise ◽  
Force Microscopy ◽  
Atomic Force ◽  
Stm Image ◽  
Surface Construction ◽  
Very High

Since Binnig, Rohrer and associates observed real-space topographic images of Si(111)-7×7 and invented the scanning tunneling microscope (STM),1) the STM has been accepted as a powerful surface science instrument.Recently, many application areas for the STM have been opened up, such as atomic force microscopy (AFM), magnetic force microscopy (MFM) and others. So, the STM technology holds a great promise for the future.The great advantages of the STM are its high spatial resolution in the lateral and vertical directions on the atomic scale. However, the STM has difficulty in identifying atomic images in a desired area because it uses piezoelectric (PZT) elements as a scanner.On the other hand, the demand to observe specimens under UHV condition has grown, along with the advent of the STM technology. The requirment of UHV-STM is especially very high in to study of surface construction of semiconductors and superconducting materials on the atomic scale. In order to improve the STM image quality by keeping the specimen and tip surfaces clean, we have built a new UHV-STM (JSTM-4000XV) system which is provided with other surface analysis capability.

scholarly journals Dental calculus: Nano-characterization

2012 ◽  
Vol 59 (3) ◽  
pp. 154-159
Author(s):  
Djurica Grga ◽  
Marina Marjanovic ◽  
Igor Hut ◽  
Bojan Dzeletovic ◽  
Djuro Koruga
Keyword(s):  
Magnetic Field Gradient ◽  
Dental Calculus ◽  
Oral Diseases ◽  
Force Microscopy ◽  
Atomic Force ◽  
Light Matter Interaction ◽  
The Magnetic Field ◽  
Very High ◽  
Insight Into

Emerging technologies and new nanoscale information have potential to transform dental practice by improving all aspects of diagnostics and therapy. Nanocharacterization allows understanding of oral diseases at molecular and cellular levels which eventually can increase the success of prevention and treatment. Opto-magnetic spectroscopy (OMS) is a promising new technique based on light-matter interaction which allows insight into the quantum state of matter. Since biomolecules and tissues are usually paramagnetic or diamagnetic materials it is possible to determine the dynamics of para-and diamagnetism at different teeth structures using that method. The topography of the surface of a sample can be obtained with a very high resolution using atomic force microscopy (AFM), which allows observation of minimal changes up to 10 nm, while magnetic force microscopy (MFM) is used to record the magnetic field gradient and its distribution over the surface of a sample. The aim of this study was to determine the possibility of AFM and MFM for the characterization of dental calculus, and a potential application of OMS for the detection of subgingival dental calculus.

Growth and Investigation of GaN/AlN Quantum Dots

2000 ◽  
Vol 639 ◽  
Author(s):  
Hadis Morkoç ◽  
Michael A. Reshchikov ◽  
Keith M. Jones ◽  
Feng Yun ◽  
Paolo Visconti ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Blue Shift ◽  
Microscopy Study ◽  
High Quantum Efficiency ◽  
Force Microscopy ◽  
Quantum Size ◽  
Atomic Force ◽  
Layer Structures ◽  
Bulk Gan ◽  
Very High

ABSTRACTWe have fabricated GaN quantum dots (QDs) in AlN confined layer structures by molecular beam epitaxy. The size distribution and density of the QDs have been estimated from an atomic force microscopy study. Very high quantum efficiency of photoluminescence (PL) has been obtained in some samples with QDs. Compared to the GaN bulk samples, it increased by orders of magnitude. In some samples the quantum size effect dominated, resulting in the blue-shift of the QD related PL peak, whereas in the samples with larger dots a red-shift up to 0.8 eV has been observed, which is related to strong polarization effects. We have observed a blue-shift of the PL peak with excitation intensity in the samples with large dots due to screening effect. The temperature-induced quenching of PL occurs at higher temperatures compared to bulk GaN due to the confinement of nonequilibrium carriers in the QDs. An excited state has been observed in some samples.

scholarly journals Evaluation of Tooth Surface Irradiated With Erbium: Yttrium Aluminum Garnet and Carbon Dioxide Lasers by Atomic Force Microscopy

2018 ◽  
Vol 9 (3) ◽  
pp. 188-193
Author(s):  
Sogol Saberi ◽  
Sooreh Seyed Jabbari Doshanlo ◽  
Hossein Bagheri ◽  
Susan Mir Mohammad Rezaei ◽  
Sima Shahabi
Keyword(s):  
Carbon Dioxide ◽  
Atomic Force Microscopy ◽  
Yttrium Aluminum Garnet ◽  
Tooth Surface ◽  
Carbon Dioxide Lasers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Yttrium Aluminum

scholarly journals New Perspectives on Tooth Wear

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Peter W. Lucas ◽  
Ridwaan Omar
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Particle Shape ◽  
Tooth Wear ◽  
Research Strategy ◽  
Tooth Surface ◽  
Wear Particles ◽  
Dental Tissues ◽  
Worn Surface ◽  
Tooth Tissue

Some of the efforts that have been made to document tooth wear are reviewed here with an emphasis on nonhuman mammals, literature with which dentists may not be very familiar. We project a change in research strategy from the description of wear at various scales of measurement towards investigation of the mechanical mechanisms that actually create the texture of a worn surface. These studies should reveal exactly how tooth tissue is lost and what aspects of the structure of dental tissues affect this. The most important aspects of the interaction between the tooth surface and wear particles would appear to be particle size, particle shape, their mechanical properties with respect to those of tooth tissues, and the influence of saliva.

scholarly journals A Comparison of Uric Acid Optical Detection Using as Sensitive Materials an Amino-Substituted Porphyrin and Its Nanomaterials with CuNPs, PtNPs and Pt@CuNPs

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2072
Author(s):  
Camelia Epuran ◽  
Ion Fratilescu ◽  
Diana Anghel ◽  
Mihaela Birdeanu ◽  
Corina Orha ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Uric Acid ◽  
Copper Nanoparticles ◽  
Hybrid Material ◽  
Human Environment ◽  
Detection Range ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Concentrations ◽  
Very High

Hybrid nanomaterials consisting in 5,10,15,20-tetrakis(4-amino-phenyl)-porphyrin (TAmPP) and copper nanoparticles (CuNPs), platinum nanoparticles (PtNPs), or both types (Pt@CuNPs) were obtained and tested for their capacity to optically detect uric acid from solutions. The introduction of diverse metal nanoparticles into the hybrid material proved their capacity to improve the detection range. The detection was monitored by using UV-Vis spectrophotometry, and differences between morphology of the materials were performed using atomic force microscopy (AFM). The hybrid material formed between porphyrin and PtNPs hasthe best and most stable response for uric acid detection in the range of 6.1958 × 10−6–1.5763 × 10−5 M, even in the presence of very high concentrations of the interference species present in human environment.

Straining Effects in Silica-Filled Elastomers Investigated by Atomic Force Microscopy: From Macroscopic Stretching to Nanoscale Strainfield

2003 ◽  
Vol 76 (1) ◽  
pp. 60-81 ◽  
Author(s):  
A. Lapra ◽  
F. Clément ◽  
L. Bokobza ◽  
L. Monnerie
Keyword(s):  
Atomic Force Microscopy ◽  
Strain Field ◽  
Local Concentration ◽  
Macroscopic Strain ◽  
Precise Description ◽  
Force Microscopy ◽  
Filled Elastomers ◽  
Atomic Force ◽  
Different Strains ◽  
Very High

Abstract Understanding the way fillers can reinforce elastomers requires, among other things, requires a precise description of the behavior of filler aggregates when a macroscopic strain is applied. In this study, Atomic Force Microscopy was used to investigate samples of SBR and PDMS filled with silica. The samples were stretched uniaxially at different strain values (up to 145%) and imaged by Atomic Force Microscopy. The distances between aggregates were followed at the different strains, which allowed calculation of the local strains and comparison of the values obtained with the macroscopic strain value. The main results are (i) that the strain field is highly heterogeneous, depending on the local concentration of filler and (ii) that the strain undergone by elastomer chains can be very high locally, in the regions where distances between aggregates are very short.

scholarly journals Nanoscale characterization of effect of l-arginine on Streptococcus mutans biofilm adhesion by atomic force microscopy

Microbiology ◽  
2014 ◽  
Vol 160 (7) ◽  
pp. 1466-1473 ◽  
Author(s):  
Shivani Sharma ◽  
Stacey Lavender ◽  
JungReem Woo ◽  
Lihong Guo ◽  
Wenyuan Shi ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Atomic Force Microscopy ◽  
Streptococcus Mutans ◽  
Oral Microbiome ◽  
Aetiological Factor ◽  
Tooth Surface ◽  
Extracellular Polysaccharides ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Atomic Force

A major aetiological factor of dental caries is the pathology of the dental plaque biofilms. The amino acid l-arginine (Arg) is found naturally in saliva as a free molecule or as a part of salivary peptides and proteins. Plaque bacteria metabolize Arg to produce alkali and neutralize glycolytic acids, promoting a less cariogenous oral microbiome. Here, we explored an alternative and complementary mechanism of action of Arg using atomic force microscopy. The nanomechanical properties of Streptococcus mutans biofilm extracellular matrix were characterized under physiological buffer conditions. We report the effect of Arg on the adhesive behaviour and structural properties of extracellular polysaccharides in S. mutans biofilms. High-resolution imaging of biofilm surfaces can reveal additional structural information on bacterial cells embedded within the surrounding extracellular matrix. A dense extracellular matrix was observed in biofilms without Arg compared to those grown in the presence of Arg. S. mutans biofilms grown in the presence of Arg could influence the production and/or composition of extracellular membrane glucans and thereby affect their adhesion properties. Our results suggest that the presence of Arg in the oral cavity could influence the adhesion properties of S. mutans to the tooth surface.

scholarly journals Epitaxial Growth of III-Nitride Layers on Aluminum Nitride Substrates

1999 ◽  
Vol 4 (S1) ◽  
pp. 411-416 ◽  
Author(s):  
L.J. Schowalter ◽  
Y. Shusterman ◽  
R. Wang ◽  
I. Bhat ◽  
G. Arunmozhi ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Electrical Characterization ◽  
High Quality ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Image Position ◽  
Nitride Layers ◽  
Very High

High quality, epitaxial growth of AlN and AlxGa1−xN by OMVPE has been demonstrated on single-crystal AlN substrates. Here we report characterization of epitaxial layers on an a-face AlN substrate using Rutherford Backscattering/ion channeling, atomic force microscopy (AFM), x-ray rocking curves, and preliminary electrical characterization. Ion channeling along the [100] axis gives a channeling minimum yield of 1.5% indicating a very high quality epitaxial layer.

Nanomechanics and morphology of salivary pellicle

2006 ◽  
Vol 21 (8) ◽  
pp. 1996-2002 ◽  
Author(s):  
Michelle E. Dickinson ◽  
Adrian B. Mann
Keyword(s):  
Tooth Surface ◽  
Viscoelastic Solid ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Chemical Attack ◽  
Atomic Force ◽  
Mechanical Measurements ◽  
Salivary Pellicle ◽  
Atomic Force Microscopy Imaging ◽  
Protein Rich

Acquired salivary pellicle is a thin protein-rich film formed by the adsorption of saliva onto teeth. It plays important roles in lubrication during mastication and protecting the teeth from chemical attack. Pellicle can become colonized by bacteria to form dental plaque which can lead to dental caries if the bacteria are acidogenic. Abrasive polishing with a dentrifice is used periodically to remove the pellicle from teeth. Pellicle can interact with dietary polyphenolic compounds (tannins) to create extrinsic stains on the tooth surface. The staining can modify the pellicle's mechanical properties and change its morphology resulting in a “squeaky” feeling when the tongue is rubbed over the teeth. Atomic force microscopy imaging and nanoscale mechanical measurements show that unstained pellicle has a dense undulating morphology and is a surprisingly stiff, viscoelastic solid. In contrast, tannin-stained pellicle has fewer but larger surface undulations and exhibits substantial viscous creep.

Sign in / Sign up

Export Citation Format

Share Document