scholarly journals Transverse microhardness of artificial teeth

2015 ◽  
Vol 21 (4) ◽  
pp. 204
Author(s):  
Regina Tamaki ◽  
Carolina Mayumi Iegami ◽  
Priscila Nakasone Uehara ◽  
Ricardo Jun Furuyama ◽  
Rafael Yague Ballester
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Repeated Measures ◽  
Knoop Hardness ◽  
The Other ◽  
Tukey Test ◽  
Knoop Microhardness ◽  
Artificial Teeth ◽  
Hardness Values

Objective: Hardness is an indicator of several mechanical properties of artificial teeth, also related to wear resistance. The purpose of this article is to map the microhardness of artificial teeth as a function of depth and commercial brand. Methods: Knoop microhardness of sectioned artificial second molars was measured every 200 µm starting at a depth of 100 µm up until 4700 µm of the following brands: Premium (Pr), Orthosit (Or), SR Postaris DCL (Po), Biotone (Bi), Artiplus IPN (Ar), VITA MFT (Vi), Natusdent (Na), Trilux (Tr), and Biolux (Bx). Results were analyzed with ANOVA for repeated measures and Tukey test (5%). Results: SR Orthosit PE commercial brand presented higher hardness values (until the depth of 3.1 mm was 30 N/mm2), significantly higher than the other brands analyzed. Conclusion: Knoop hardness did not present differences between layers for eight of the nine brands studied. Different hardness values were found between superficial and cervical areas for the brand SR Orthosit PE.

Improving the wear resistance of Al–Si alloy by ion implantation

1997 ◽  
Vol 12 (12) ◽  
pp. 3246-3249 ◽  
Author(s):  
Y. Itoh ◽  
H. Azuma ◽  
A. Itoh ◽  
T. Hioki
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Ion Implantation ◽  
Sample Surface ◽  
Knoop Hardness ◽  
The Other ◽  
Xps Analysis ◽  
Cross Sectional ◽  
Steel Balls ◽  
Ion Implanted

The mechanical properties of ion-implanted Al–Si alloy were studied using disk samples of alloy irradiated with Ar+, B+, and N2+ ions. Knoop hardness of ASTM 336.0 disks increased from 117 to 165 kgf/mm2 upon N2+ ion implantation. To measure tribological properties, lubricated ball-on-disk tests were performed using steel balls. The coefficients of friction of ion-implanted disks were higher than those of unimplanted ones. Ion implantation improved the wear resistance of the disks, and in the case of N2+ ion-implanted disks, the worn volume was smaller than 10−4 mm3. XPS analysis for the N2+ ion-implanted samples revealed the formation of aluminum and silicon nitride on the sample surface. On the other hand, the cross-sectional image of the ion-implanted surface showed precipitated Si which is held under the implanted N2+ ions.

scholarly journals Artificial teeth: evaluation of wear resistance, microhardness and composition

2015 ◽  
Vol 63 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Matheus GRANDO ◽  
Lívia Muniz PACHECO ◽  
Daniela Maffei BOTEGA ◽  
Luciana Mayumi HIRAKATA ◽  
Juliana Balbinot HILGERT
Keyword(s):  
Wear Resistance ◽  
Acrylic Resin ◽  
Knoop Hardness ◽  
Composition Analysis ◽  
Bonferroni Correction ◽  
Hardness Tester ◽  
Significant Difference ◽  
Microhardness Testing ◽  
Wear Evaluation ◽  
Artificial Teeth

Objective: To evaluate the Knoop hardness, composition, and wear resistance of acrylic-resin artificial teeth exposed to mechanical toothbrushing. Methods: Artificial teeth from three commercial brands - Biotone, Trilux, and Soluut PX - were used. From each brand, 10 teeth were selected for wear evaluation after mechanical brushing, 10 for microhardness testing, and 5 for composition analysis. Specimens underwent 55,000 brushing cycles, under a 200-g load and at a frequency of 250 cycles per minute, using a soft-bristled toothbrush (IndicatorPlus 30, Oral-B) soaked in a 1:1 toothpaste/water slurry (Oral B Pró Saúde). Microhardness testing was performed using a 25-g load for 15 seconds in an HMV-2 hardness tester (Shimadzu). The composition of teeth from different brands was determined by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) (Jeol JSM 5800). Results: Wear results after mechanical brushing were compared by means of the paired t-test, whereas those obtained in microhardness testing were compared by ANOVA with Bonferroni correction. There was no statistically significant difference between brands in either trial. Conclusion: Composition analysis revealed that all of the artificial teeth analyzed contain carbon and oxygen. Trilux and Soluut PX brand teeth also contain silicon; however, the presence of filler particles did not result in increased resistance.

scholarly journals Influence of Different Pigmentations and Accelerated Aging on the Hardness and Tear Strength of the A-2186 and MDX4-4210 Silicones

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Estefânia Marrega Malavazi ◽  
Daniela Micheline dos Santos ◽  
Clóvis Lamartine de Moraes Melo Neto ◽  
Fernanda Pereira de Caxias ◽  
Emily Vivianne Freitas da Silva ◽  
...  
Keyword(s):  
Analysis Of Variance ◽  
Repeated Measures ◽  
Accelerated Aging ◽  
Hardness Test ◽  
Strength Test ◽  
Tear Strength ◽  
Tukey Test ◽  
Repeated Measures Analysis ◽  
Before And After ◽  
Hardness Values

Objective. To evaluate the influence of different pigmentations and accelerated aging on the hardness and tear strength of the A-2186 and MDX4-4210 silicones. Materials and Methods. The samples A-2186 and MDX4-4210 were manufactured without and with pigmentations (black, bronze, and pink). For the Shore A hardness test, 80 samples of each silicone were fabricated, and for the tear strength test, 320 samples of each silicone were fabricated. Eight groups were created for each test (n = 10). These tests were performed before and after 252, 504, and 1008 hours of aging. Three-way repeated-measures analysis of variance and the Tukey test were performed (α = 0.05). Results. The A-2186 silicone showed higher hardness and tear strength when compared with the MDX4-4210 silicone p<0.05, except in the hardness of the A-2186 and MDX4-4210 groups without pigmentation after 1008 hours p>0.05. All hardness values were between 25 and 35 units, regardless of the silicone type, period, and pigmentation (or no pigmentation). In most situations, the hardness of silicones used increased after 252 hours p<0.05. The nonpigmented MDX4-4210 group and all A-2186 groups showed an increase in tear strength after 252 hours p<0.05. For the nonpigmented MDX4-4210 group, from 252 to 1008 hours, there was no change in tear strength p>0.05. All pigmented MDX4-4210 groups showed no change in tear strength from 0 (initial) to 1008 hours of aging p>0.05. In all A-2186 groups, from 252 to 504 hours, there was a reduction in tear strength p<0.05, and from 504 to 1008 hours, there was an increase in tear strength p<0.05, except in the bronze A-2186 group p>0.05. Conclusion. In most situations, the A-2186 silicone showed significantly higher values of hardness and tear strength than the MDX4-4210 silicone. All hardness values were considered clinically acceptable. Accelerated aging could increase, decrease, or not significantly change the hardness and tear strength of the silicones used. The results of hardness and tear strength suggest that MDX4-4210 was more influenced by the presence of pigmentation after aging.

scholarly journals Tribological behavior of wire-EDM’ed ZrO2 composites and cemented carbides

2010 ◽  
Vol 1 (1) ◽  
pp. 68-72
Author(s):  
Yeczain Perez Delgado ◽  
Koen Bonny ◽  
Patrick De Baets ◽  
O. Malek ◽  
J. Vleugels ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Strong Influence ◽  
Tribological Behavior ◽  
Secondary Phase ◽  
The Other ◽  
Cemented Carbides ◽  
Wire Edm ◽  
Dry Conditions ◽  
Phase Surface

Five ZrO2-based composites (ZrO2-WC, ZrO2-TiCN and ZrO2-TiN grades) and five WC-Co cemented carbide grades were machined by wire-EDM and tested on a linearly reciprocating sliding pin-on-flat tribometer PLINT TE77 in dry conditions against WC-6wt%Co pins. Measurement of friction coefficient and penetration depth due to wear was performed continuously. The results revealed a strong influence of the secondary phase, surface finish, chemical and mechanical properties on the tribological characteristics of the ZrO2-based composites and cemented carbides. WC10Co(Cr/V) displayed superior wear resistance compared to the other grades. The lowest coefficient of friction was encountered with ZrO2-WC.

scholarly journals Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition

2015 ◽  
Vol 60 (1) ◽  
pp. 483-490 ◽  
Author(s):  
D. Myszka ◽  
A. Wieczorek
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Ductile Iron ◽  
Surface Hardening ◽  
The Other ◽  
Austempered Ductile Iron ◽  
High Wear Resistance ◽  
New Materials ◽  
Heat Treated ◽  
Mining Machinery

Abstract The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.

Wear behaviour of polyurethane composites with respect to the other mechanical properties

2014 ◽  
Vol 11 (2) ◽  
pp. 139-146
Author(s):  
Anna Porąbka ◽  
Vasiliki-Maria Archodoulaki ◽  
Wolfgang Molnar ◽  
Jadwiga Laska
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Different Temperatures ◽  
Polyurethane Composites ◽  
Polyurethane Matrix ◽  
Properties Of Composites

Two series of polyurethane matrix composites were prepared. As generally resistant to wear, the PUs can be used as matrices for wear protective and load-bearing composites. The objective of this study was to compare the mechanical properties of composites containing 5% vol. of selected ceramic particles, and unmodified PUs. The effect of various particles on physical and mechanical properties was studied. The results showed that the mechanical properties changed compared to reference materials: modulus improved in certain materials and in different temperatures, revealing the favourable influence of FA and SiO2 particles. In turn, Rm and wear resistance decreased with the type and shape of filler.

Microhardness of 6H- and 4H-SiC Substrates

2009 ◽  
Vol 615-617 ◽  
pp. 323-326 ◽  
Author(s):  
Charles R. Eddy ◽  
Ping Wu ◽  
Ilya Zwieback ◽  
Brenda L. VanMil ◽  
Rachael L. Myers-Ward ◽  
...  
Keyword(s):  
Knoop Hardness ◽  
General Application ◽  
Crystal Direction ◽  
Nitrogen Doped ◽  
Knoop Microhardness ◽  
Hardness Values

Knoop microhardness assessments were conducted on a variety of 6H- and 4H-SiC substrates to assess any appreciable differences that may need to be considered in wafer manufacture and general application. Nitrogen-doped, vanadium-doped and unintentionally doped (UID) substrates with both on-axis and 8° off-axis orientations were assessed. In general, the Knoop hardness values fell in the 2000 to 2500 kg/mm2 range (equivalent to approximately 20 to 25 GPa). Hardness values measured in the <1100> crystal direction were significantly higher than in the <11-20> direction. Undoped and vanadium-doped samples were harder than nitrogen-doped samples. For both 6H and 4H nitrogen-doped samples, the hardness was as much as 10% higher for 8° offcut wafers than for on-axis.

scholarly journals Influence of light curing source on microhardness of composite resins of different shades

2006 ◽  
Vol 14 (1) ◽  
pp. 10-15 ◽  
Author(s):  
André Luiz Fraga Briso ◽  
Tânia Maria Fedel ◽  
Sibéria de Morais Pereira ◽  
Sílvio José Mauro ◽  
Renato Herman Sundfeld ◽  
...  
Keyword(s):  
Light Intensity ◽  
Confidence Level ◽  
Composite Resin ◽  
Composite Resins ◽  
The Other ◽  
Light Sources ◽  
Low Light ◽  
Tukey Test ◽  
Light Curing ◽  
Hardness Values

INTRODUCTION: The evolution of light curing units can be noticed by the different systems recently introduced. The technology of LED units promises longer lifetime, without heating and with production of specific light for activation of camphorquinone. However, further studies are still required to check the real curing effectiveness of these units. PURPOSE: This study evaluated the microhardness of 4 shades (B-0.5, B-1, B-2 and B-3) of composite resin Filtek Z-250 (3M ESPE) after light curing with 4 light sources, being one halogen (Ultralux - Dabi Atlante) and three LED (Ultraled - Dabi Atlante, Ultrablue - DMC and Elipar Freelight - 3M ESPE). METHODS: 192 specimens were distributed into 16 groups, and materials were inserted in a single increment in cylindrical templates measuring 4mm x 4mm and light cured as recommended by the manufacturer. Then, they were submitted to microhardness test on the top and bottom aspects of the cylinders. RESULTS: The hardness values achieved were submitted to analysis of variance and to Tukey test at 5% confidence level. It was observed that microhardness of specimens varied according to the shade of the material and light sources employed. The LED appliance emitting greater light intensity provided the highest hardness values with shade B-0.5, allowing the best curing. On the other hand, appliances with low light intensity were the least effective. It was also observed that the bottom of specimens was more sensitive to changes in shade. CONCLUSION: Light intensity of LED light curing units is fundamental for their good functioning, especially when applied in resins with darker shades.

Effects of Different Preparation Parameters on the Properties of MAO Coatings

2014 ◽  
Vol 609-610 ◽  
pp. 14-19 ◽  
Author(s):  
Xin Wu ◽  
Qing Min Liu ◽  
Hong Xia Li
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Wear Resistance ◽  
Current Density ◽  
Ceramic Coating ◽  
Electrolyte Concentration ◽  
Measurement Properties ◽  
Micro Hardness ◽  
Micro Arc Oxidation ◽  
Hardness Values

Effects of different preparation parameters on the structural and mechanical properties of micro-arc oxidation coatings prepared in silicate electrolyte on 6063 alloy were investigated. The results show that the growth rate of ceramic coating increases with increasing current density and electrolyte concentration. The prepared coating had denser and smoother surface with few defects, higher micro-hardness values and better wear resistance when the current density was increased to 20A/dm2. The measurement properties were all up to their optimum values when the electrolyte concentration was in the range of 9-12g/l and oxidation time was 60min, respectively.

scholarly journals Properties of TiC Coating by Pulsed DC PACVD

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mahboobeh Azadi ◽  
Alireza Sabour Rouhaghdam ◽  
Shahrokh Ahangarani
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Wear Resistance ◽  
Flow Rate ◽  
Gas Flow ◽  
High Hardness ◽  
Grazing Incidence ◽  
Knoop Hardness ◽  
Flow Rate Ratio ◽  
Pulsed Dc

In the PACVD technique, temperature and gas flow rate are two important parameters affecting the coating characteristics. Effect of these parameters on mechanical behaviors of TiC coating that was deposited on hot work tool steel (H13) was investigated in this paper. We analyzed TiC coating composition and structure with grazing incidence X-ray diffraction (GIXRD) and Fourier transformation infrared spectroscopy (FTIR). The mechanical properties of the coatings, such as microhardness, wear resistance, and surface roughness, were studied with Knoop hardness indentation, pin on disk wear tests, and atomic force microscopy, respectively. When the deposition temperature decreased from 490°C to 450°C and the CH4 to TiCl4 flow rate ratio was also increased from 1.5 to 6, TiC coating color changed from dark gray to silver. The best mechanical properties such as a high hardness (27 GPa), wear resistance, and low surface roughness were related to the coating that was deposited at 450°C.

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