scholarly journals DEVICE FOR IN VITRO WEAR ANALYSIS OF BIOMATERIALS IN THE HINGED PROSTHESIS CONFIGURATION

2018 ◽  
Vol 16 (3) ◽  
pp. 381
Author(s):  
José N. Atahyde ◽  
Beatriz L. Fernandes ◽  
Carlos J. de M. Siqueira ◽  
Percy Nohama ◽  
Carlos R. Fernandes
Keyword(s):  
Wear Behavior ◽  
Knee Prosthesis ◽  
Hertzian Contact ◽  
Compression Load ◽  
Scientific Investigations ◽  
Wear Analysis ◽  
Test Parameters ◽  
Hertzian Contact Stress ◽  
Movement Simulation

We have developed a device that, coupled to the tribometer, allows movement simulation of the hinged type knee prosthesis. Two tests were performed using the samples designed and one test without the device using a pin-on-flat configuration. For the first and the third tests, the metallic samples were used as machined while for the second one they were electrolytically polished. The test parameters were running length of 0.663 rad and compression load of 22.35 N. The Hertzian contact stress of 15.93 MPa obtained between the samples designed is close to that for the real prosthesis. The measured volumetric wear revealed the influence of roughness of the counterpart surface on the wear behavior. The device has allowed its coupling to the tribometer without any interference on its functioning thus making a contribution to the scientific investigations related to wear behavior of a couple of different biomaterials.

Factors Affecting the Wear Behavior of Monolithic Zirconia and the Antagonists: Literature Review

2020 ◽  
Vol 2 (1) ◽  
pp. 4-11
Author(s):  
Marcia Borba ◽  
Paula Benetti ◽  
Giordana P. Furini ◽  
Kátia R. Weber ◽  
Tábata M. da Silva
Keyword(s):  
Literature Review ◽  
Glass Ceramic ◽  
Wear Behavior ◽  
Glass Ceramics ◽  
Surface Treatments ◽  
Human Tooth ◽  
Initial Surface ◽  
Monolithic Zirconia ◽  
Feldspathic Porcelain

Background: The use of zirconia-based ceramics to produce monolithic restorations has increased due to improvements in the optical properties of the materials. Traditionally, zirconiabased ceramics were veneered with porcelain or glass-ceramic and were not directly exposed to the oral environment. Therefore, there are several doubts regarding the wear of the monolithic zirconia restoration and their antagonists. Additionally, different surface treatments are recommended to promote a smooth surface, including glaze and several polishing protocols. To support the correct clinical application, it is important to understand the advantages and limitations of each surface treatment. Objective: The aim of this short literature review is to investigate the factors that may affect the wear of monolithic zirconia restorations in service and their antagonists. Methods: Pubmed/Medline database was accessed to review the literature from a 10-year period using the keywords: zirconia, monolithic, prosthesis, wear. Both clinical and in vitro studies were included in the review. Results: Studies investigated the effect of several surface treatments, including grinding with diamond- burs, polishing and glazing, on the surface roughness, phase transformation and wear capacity of monolithic zirconia. The wear behavior of monolithic zirconia was frequently compared to the wear behavior of other ceramics, such as feldspathic porcelain, lithium disilicate-based glassceramic and leucite-reinforced glass-ceramic. Human tooth, ceramics and resin composites were used as antagonist in the investigations. Only short-term clinical studies are available (up to 2 years). Conclusion: Literature findings suggest that zirconia monolithic restorations are wear resistant and unlikely to cause excessive wear to the antagonist, especially when compared to feldspathic porcelain and glass-ceramics. Monolithic zirconia should be polished rather than glazed. Yet, none of the polishing systems studied was able to completely restore the initial surface conditions of zirconia after being adjusted with burs. More clinical evidence of the antagonist tooth wear potential of monolithic zirconia is needed.

Surface Durability of Spur Gears at Hertzian Stresses Over Shakedown Limit

1974 ◽  
Vol 96 (2) ◽  
pp. 359-372 ◽  
Author(s):  
Akira Ishibashi ◽  
Taku Ueno ◽  
Shigetada Tanaka
Keyword(s):  
Fatigue Testing ◽  
Testing Machine ◽  
Carbon Steels ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Load Testing ◽  
Short Period ◽  
Hertzian Contact Stress ◽  
Surface Durability ◽  
Shakedown Limit

Using a new type of gear-load testing machine and a disk-type rolling fatigue testing machine designed and made by the authors, the upper limits of Hertzian contact stress allowable on rolling contact surfaces were investigated. It was shown conclusively that gears and rollers made of soft carbon steels could be rotated beyond 108 revolutions at Hertzian stresses over shakedown limit (≈ 0.4 HB). In the case of gears, pits having a pitting area ratio of 0.04 percent occurred during 1.16 × 108 rotations at a Hertzian stress of 0.50 HB. However, no pitting occurred on the roller rotated through 1.20 × 108 revolutions at a Hertzian stress of 0.71 HB, although appreciable changes in texture were observed at the subsurface. In order to rotate gears or rollers at Hertzian stresses over shakedown limit, their surface must either be very smooth initially or after a short period of running, and an oil film must be formed between contacting surfaces.

Friction and Wear Analysis of Deep Rolled and Vibrorolled Specimens in Lubricated Contact

2018 ◽  
Vol 767 ◽  
pp. 93-100
Author(s):  
Fritz Klocke ◽  
Anton Shirobokov ◽  
Rafael Hild ◽  
Andreas Feuerhack ◽  
Daniel Trauth ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Surface Treatment ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Shear Stresses ◽  
Deep Rolling ◽  
Microscopy Imaging ◽  
Friction And Wear Behavior ◽  
Wear Analysis

Deep rolling is an established mechanical surface treatment technology based on local plastic deformation of the surface layer. By these means, residual stresses, and strain hardening are induced into the surface layer as well as its surface structure is smoothed. Vibrorolling is a derivate technology of deep rolling characterized by sinusoidal rolling lanes. Due to process kinematics of vibrorolling the surface layer is incrementally deformed multiple times in different directions. As a result, a more intensive plastic deformation of the surface layer is achieved and potentially tribologically active surface structures are produced. To investigate and compare the effects of both surface treatment technologies on the tribological behavior of a processed component, a friction and wear analysis under lubricated conditions was conducted in this work. Friction and wear behavior of untreated, deep rolled, and vibrorolled specimens using a pin-on-cylinder tribometer was conducted. Hardness, roughness, and geometrical measurements of the wear traces were used to characterize the specimens. Additionally, qualitative assessments of the wear traces using scanning electron microscopy imaging were made. The measurements were performed before, during, and after the friction and wear analysis. Furthermore, contact forces between a tribometer pin and the workpiece were determined to analyze the development of contact shear stresses. Based on the conducted investigations, the effects of deep rolling and vibrorolling on the friction and wear behavior of the treated specimens are discussed and explanations for the observed phenomena are formulated in this work.

Influence of Cyclic Loading on Mechanical Loosening of Hinged Knee Prostheses

1978 ◽  
Vol 7 (4) ◽  
pp. 235-239 ◽  
Author(s):  
D. H. van Campen ◽  
H. W. Croon ◽  
J. Lindwer
Keyword(s):  
Experimental Investigation ◽  
Cyclic Loading ◽  
Mechanical Loading ◽  
Knee Prosthesis ◽  
In Vitro Experiments ◽  
Knee Prostheses ◽  
Normal Walking ◽  
Fresh Cadaver ◽  
Unfavourable Effect

A combined theoretical and experimental investigation is reported with respect to the influence of mechanical loading on loosening at the cement bone interface of knee prostheses with intermedullary stems. The in vitro experiments have been performed under cyclic loading conditions with the tibial part of a Shiers knee prosthesis implanted in fresh cadaver tibiae. The experimental results indicate an unfavourable effect of peak loading (as occurring in walking up stairs) on loosening as compared with loading due to normal walking conditions.

Investigation on Biocompatibility and Mechanical Properties of Ti15Mg Alloy

2021 ◽  
Vol 1039 ◽  
pp. 557-564
Author(s):  
Haydar Abdul Hassan Al-Ethari ◽  
Sundus Abbas Jasim ◽  
Ekhlas Khalid Zamel
Keyword(s):  
Mechanical Properties ◽  
Wear Behavior ◽  
Research Work ◽  
Wear Test ◽  
Optical Microscope ◽  
Alloy Sample ◽  
Microscope Analysis ◽  
Good Biocompatibility ◽  
Prepared Alloy

In this research work, bioactive Ti15Mg alloy was prepared by powder metallurgy route to investigate its biocompatibility and mechanical properties. Many tests were performed including X-ray diffraction; optical microscope analysis, scanning electron microscope analysis, ultrasonic wave test, corrosion behavior test, Static immersion test, and the wet sliding wear test. The XRD result shows that the prepared alloy sample consist of (α-Ti phase) and Mg. The microstructure of the prepared alloy sample consisted of a biodegradable Mg or pore and alpha titanium. The effect of the Mg content on degradability was tested based on simulated body fluid of Ringer solutions using electrochemical corrosion. The findings indicate that an elastic modulus of 47GPa exhibits the alloy. There were low corrosion rates of the alloy. The Ti matrix remained integrity after 14 days of immersion in the Ringer solutions, and the magnesium phase dissolved in the solution, causing a layer to form on the alloy. The wear behavior of the prepared ally at wet sliding conditions was evaluated using pin on disc method. The in vitro analysis showed good biocompatibility with Ti15Mg alloy. The prepared alloy demonstrates good biocompatibility and bioactivity.

Effect of Lubricant on Surface Rolling Contact Fatigue Cracks

2010 ◽  
Vol 97-101 ◽  
pp. 793-796 ◽  
Author(s):  
Khalil Farhangdoost ◽  
Mohammad Kavoosi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Element Analysis ◽  
Crack Face ◽  
Hertzian Contact Stress ◽  
Model Of Friction

This study performed the finite element analysis of the cycle of stress intensity factors at the surface initiated rolling contact fatigue crack tip under Hertzian contact stress including an accurate model of friction between the faces of the crack and the effect of fluid inside the crack. A two-dimensional model of a rolling contact fatigue crack has been developed with FRANC-2D software. The model includes the effect of Coulomb friction between the faces of the crack. The fluid in the crack was assumed not only to lubricate the crack faces and reduce the crack face friction coefficient but also to generate a pressure.

Energy Losses of Balls Rolling on Plates

1959 ◽  
Vol 81 (2) ◽  
pp. 233-238 ◽  
Author(s):  
R. C. Drutowski
Keyword(s):  
Surface Roughness ◽  
Rolling Force ◽  
Primary Source ◽  
Sample Surface ◽  
Hertzian Contact ◽  
Energy Losses ◽  
Cyclic Process ◽  
Damping Capacity ◽  
Hertzian Contact Stress ◽  
Point To Point

The apparatus for measuring the rolling force of a ball supported between two plates is described. The rolling force is an extremely small quantity compared to the normal force. Instantaneous values of the rolling force vary greatly from point to point on the sample surface and this variation is explained in terms of surface roughness and material homogeneity. The energy losses of balls rolling on plates are shown as functions of load, material, and surface roughness. The rolling of a ball on a plate is examined as a cyclic process in which elastic hysteresis losses appear to be the primary source of energy dissipation. An analysis involving the Hertzian contact stress field is used to derive an equation relating the rolling force and the material damping capacity.

Wear Analysis of Functionally Gradient Composite Materials by FE Modelling of Microhardness Measurements and Wear Tests

2007 ◽  
Vol 537-538 ◽  
pp. 519-526
Author(s):  
David Felhös ◽  
Karoly Váradi ◽  
Klaus Friedrich
Keyword(s):  
Wear Behavior ◽  
Gradient Material ◽  
Material Structure ◽  
Fe Modelling ◽  
Sem Images ◽  
Wear Analysis ◽  
Functionally Gradient ◽  
Sic Reinforcement ◽  
Wear Tests ◽  
Functionally Gradient Composite

Rollers of three different material structures were examined: rollers consisting of pure EP resin; homogeneous EP/SiC composite rollers containing 5 vol.% SiC; and EP/SiC composite rollers with functionally gradient (FG) material structure. Wear tests were performed on the rollers. The wear tests showed that rollers of gradient structure are the most wear-resistant of all. Microhardness measurements were performed on the materials of the three different rollers. SEM images were made of the surface of wear traces. In order to get to know better the effect of SiC reinforcement particles on the wear mechanism, microhardness measurements were simulated by 3D FE micro-models. The SEM images and the FE models were used to explain the excellent wear behavior of the tread of rollers with gradient material distribution.

scholarly journals Assessing Effects of BHV-0223 40 mg Zydis Sublingual Formulation and Riluzole 50 mg Oral Tablet on Liver Function Test Parameters Utilizing DILIsym

2020 ◽  
Vol 175 (2) ◽  
pp. 292-300
Author(s):  
Diane M Longo ◽  
Lisl K M Shoda ◽  
Brett A Howell ◽  
Vladimir Coric ◽  
Robert M Berman ◽  
...  
Keyword(s):  
Clinical Data ◽  
Liver Toxicity ◽  
Hepatic Metabolism ◽  
In Vitro Toxicity ◽  
Oral Tablet ◽  
Test Parameters ◽  
First Pass ◽  
Function Test ◽  
Lateral Sclerosis

Abstract For patients with amyotrophic lateral sclerosis who take oral riluzole tablets, approximately 50% experience alanine transaminase (ALT) levels above upper limit of normal (ULN), 8% above 3× ULN, and 2% above 5× ULN. BHV-0223 is a novel 40 mg rapidly sublingually disintegrating (Zydis) formulation of riluzole, bioequivalent to conventional riluzole 50 mg oral tablets, that averts the need for swallowing tablets and mitigates first-pass hepatic metabolism, thereby potentially reducing risk of liver toxicity. DILIsym is a validated multiscale computational model that supports evaluation of liver toxicity risks. DILIsym was used to compare the hepatotoxicity potential of oral riluzole tablets (50 mg BID) versus BHV-0223 (40 mg BID) by integrating clinical data and in vitro toxicity data. In a simulated population (SimPops), ALT levels > 3× ULN were predicted in 3.9% (11/285) versus 1.4% (4/285) of individuals with oral riluzole tablets and sublingual BHV-0223, respectively. This represents a relative risk reduction of 64% associated with BHV-0223 versus conventional riluzole tablets. Mechanistic investigations revealed that oxidative stress was responsible for the predicted ALT elevations. The validity of the DILIsym representation of riluzole and assumptions is supported by its ability to predict rates of ALT elevations for riluzole oral tablets comparable with that observed in clinical data. Combining a mechanistic, quantitative representation of hepatotoxicity with interindividual variability in both susceptibility and liver exposure suggests that sublingual BHV-0223 confers diminished rates of liver toxicity compared with oral tablets of riluzole, consistent with having a lower overall dose of riluzole and bypassing first-pass liver metabolism.

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