scholarly journals A new hand-held optical reflectometer to measure enamel erosion: correlation with surface hardness and calcium release

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Thiago Saads Carvalho ◽  
Tommy Baumann ◽  
Adrian Lussi
Keyword(s):  
Calcium Release ◽  
Surface Hardness ◽  
Enamel Erosion ◽  
Optical Reflectometer

scholarly journals A New Sugarcane Cystatin Strongly Binds to Dental Enamel and Reduces Erosion

2017 ◽  
Vol 96 (9) ◽  
pp. 1051-1057 ◽  
Author(s):  
A.C. Santiago ◽  
Z.N. Khan ◽  
M.C. Miguel ◽  
C.C. Gironda ◽  
A. Soares-Costa ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
Surface Hardness ◽  
Dental Enamel ◽  
Reversible Inhibitors ◽  
Force Microscopy ◽  
Atomic Force ◽  
Enamel Erosion ◽  
Acquired Enamel Pellicle

Cystatin B was recently identified as an acid-resistant protein in acquired enamel pellicle; it could therefore be included in oral products to protect against caries and erosion. However, human recombinant cystatin is very expensive, and alternatives to its use are necessary. Phytocystatins are reversible inhibitors of cysteine peptidases that are found naturally in plants. In plants, they have several biological and physiological functions, such as the regulation of endogenous processes, defense against pathogens, and response to abiotic stress. Previous studies performed by our research group have reported high inhibitory activity and potential agricultural and medical applications of several sugarcane cystatins, including CaneCPI-1, CaneCPI-2, CaneCPI-3, and CaneCPI-4. In the present study, we report the characterization of a novel sugarcane cystatin, named CaneCPI-5. This cystatin was efficiently expressed in Escherichia coli, and inhibitory assays demonstrated that it was a potent inhibitor of human cathepsins B, K, and L ( Ki = 6.87, 0.49, and 0.34 nM, respectively). The ability of CaneCPI-5 to bind to dental enamel was evaluated using atomic force microscopy. Its capacity to protect against initial enamel erosion was also tested in vitro via changes in surface hardness. CaneCPI-5 showed a very large force of interaction with enamel (e.g., compared with mucin and casein) and significantly reduced initial enamel erosion. These results suggest that the inclusion of CaneCPIs in dental products might confer protection against enamel erosion.

Salivary Hemoglobin Protects against Erosive Tooth Wear in Gastric Reflux Patients

2020 ◽  
Vol 54 (5-6) ◽  
pp. 466-474 ◽  
Author(s):  
Tatiana Martini ◽  
Daniela Rios ◽  
Aline Dionizio ◽  
Luiza de Paula Silva Cassiano ◽  
Vinicius Taioqui Pelá ◽  
...  
Keyword(s):  
Proteinase Inhibitors ◽  
Surface Hardness ◽  
Group Versus ◽  
Tooth Wear ◽  
Biological Factor ◽  
Α Subunit ◽  
Erosive Tooth Wear ◽  
Increased Risk ◽  
Enamel Erosion

<b><i>Objective:</i></b> Saliva is the most important biological factor to protect against erosive tooth wear (ETW). Gastroesophageal reflux disease (GERD) patients have an increased risk of ETW due to the frequent presence of intrinsic acids in the oral cavity. Remarkably, not all GERD patients suffer from ETW, which might be due to differences in the composition of the saliva. <b><i>Methods:</i></b> This study compared the proteomic profile of saliva in patients (1) with GERD and ETW (basic erosive wear examination, BEWE, score ≥9; GE group) and (2) with GERD without ETW (BEWE = 0; GNE group) using shotgun label-free quantitative proteomic analysis nLC-ESI-MS/MS. The ability of hemoglobin (Hb) to protect against initial enamel erosion caused by a daily 10-s immersion of enamel specimens in 0.01 M HCl (pH 2.3) for 3 days was evaluated in vitro for proof of concept. Surface hardness change was used as response variable. <b><i>Results:</i></b> The differential expression of Hb subunits was significantly increased in the GNE group versus the GE group, in particular the Hb α-subunit that showed a &#x3e;22-fold increase. Expressions of serum albumin (4.5-fold) and isoforms of cytoskeletal keratin type II (&#x3e;3-fold) were also increased in the GNE group. Proteinase inhibitors, such as α<sub>1</sub>-antitrypsin and α<sub>2</sub>-macroglobulin, were only identified in the GNE group. In vitro, Hb (1.0 and 4.0 mg/mL) significantly reduced initial enamel erosion compared to a negative control after 3 days. <b><i>Conclusions:</i></b> Our results indicate that many proteins, with special emphasis on Hb, may be involved in the resistance of GERD patients to the occurrence of ETW. These proteins may be candidates for inclusion in dental products to protect against ETW.

Membrane Changes in Polymorphonuclear Leukocytes During Ionophore (A23187) - Induced Lysosomal Release

1977 ◽  
Vol 35 ◽  
pp. 482-483
Author(s):  
P.L. Moore ◽  
P.L. Sannes ◽  
H.L. Bank ◽  
S.S. Spicer
Keyword(s):  
Structural Changes ◽  
Calcium Release ◽  
Clear Understanding ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Extracellular Medium ◽  
Pmn Leukocytes ◽  
Intracellular Ion Concentrations ◽  
Membrane Changes ◽  
Pmn Leukocyte

It is thought that calcium and/or magnesium may play important roles in polymorphonuclear (PMN) leukocyte functions such as chemotaxis, adhesion and phagocytosis. Yet, a clear understanding of the biological roles of these ions has awaited the development of techniques which permit a selective alteration of intracellular ion concentrations. Recently, treatment of cells with the ionophore A23187 has been used to alter intracellular divalent cation concentrations. This ionophore is a lipid soluble antibiotic produced by Streptomyces chartreusensis that complexes with both calcium and magnesium (3) and is believed to carry these ions across biological membranes (4). Biochemical investigations of human PMN leukocytes demonstrate that cells treated with A23187 and extracellular calcium release their lysosomal enzymes into the extracellular medium without rupturing and releasing their soluble cytoplasmic enzymes (5,6). The aim of the present study and and a companion report (7) was to investigate the structural changes that occur in leukocytes during ionophore-induced lysosomal enzyme release.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

Effect of light intensity and water aging on surface hardness of dental resin-composites

2019 ◽  
Vol 64 (11) ◽  
pp. 1007-1014
Author(s):  
Tong XU ◽  
◽  
Jia-Hui ZHANG ◽  
Zhao-Ying LIU ◽  
Xuan LI ◽  
...  
Keyword(s):  
Light Intensity ◽  
Surface Hardness ◽  
Resin Composites ◽  
Dental Resin ◽  
Dental Resin Composites ◽  
Effect Of Light

OPTICAL REFLECTOMETER BASED ON THE METHOD OF SPECTRAL INTERFEROMETRY

2016 ◽  
Vol 75 (1) ◽  
pp. 59-70 ◽  
Author(s):  
K. A. Lukin ◽  
D. N. Tatyanko ◽  
Yu. A. Shiyan ◽  
L. V. Yurchenko ◽  
A.V. Bazakutsa
Keyword(s):  
Spectral Interferometry ◽  
Optical Reflectometer

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

DILLIDUR 450V

Alloy Digest ◽  
2011 ◽  
Vol 60 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Room Temperature ◽  
Surface Hardness ◽  
Heat Treating ◽  
Hot Working ◽  
Resistant Steel ◽  
Bend Strength

Abstract Dillidur 450V is a water hardened wear-resistant steel with surface hardness at room temperature of 420-480 HB. The steel is easy to weld and bend. Hot working is not recommended. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on wear resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-638. Producer or source: Dillinger Hütte GTS.

NITRODUR 8524

Alloy Digest ◽  
2017 ◽  
Vol 66 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Fatigue Strength ◽  
Tensile Properties ◽  
High Temperatures ◽  
High Surface ◽  
Surface Hardness ◽  
Operating Temperatures

Abstract NITRODUR 8524 (8CrMo16, 1.8524) is one of the Nitrodur family of nitriding steels that are used where high surface hardness and good fatigue strength are required and the material is also subjected to high temperatures. Nitrided surfaces maintain their hardness and strength at operating temperatures of up to approximately 500–550 deg C (932–1022 deg F). This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as casting and forming. Filing Code: SA-807. Producer or source: Schmolz + Bickenbach Group.

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