This study was focused on the experimental investigations about mechanical characteristics and tribological mechanisms of nanometric zirconia dental ceramics. A universal mechanical testing machine was used to test the threepoint flexural strength and the fracture toughness. A microhardness tester was used to test the Vickers hardness of the test specimens. An MRH-3 digital-display high-speed r...

During the last two decades, improvements in hip and knee designs, bearing materials, sterilisation techniques, oxidation stabilisation, and articulating surface treatments have led to superior performance of total hip and knee arthroplasties by reducing the prevalence of wear, delamination, and structural material fatigue. These advances are expected to show substantial benefits in decreasing ...

The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially ...

Using high-resolution, in situ imaging of a hard, wedge-shaped model asperity sliding against a metal surface, we demonstrate a new mechanism for particle formation and delamination wear. Damage to the residual surface is caused by the occurrence of folds on the free surface of the prow-shaped region ahead of the wedge. This damage manifests itself as shallow crack-like features and surface tea...

In laboratory tests, the ultra-high molecular weight polyethylene used for the acetabular cups of Charnley hip prostheses has a very low wear rate against steel. In the body radiographic measurements indicate that the polyethylene wears more rapidly. In order to investigate this higher wear rate, the sockets of acetabular cups removed at post-mortem have been examined using optical and electron...

background: the interim restorative materials should have certain mechanical properties to withstand in oral cavity. the aim of this study was to evaluate the hardness and wear resistance ofinterim restorative materials. materials and methods: fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (tempspan, protemp 3 garant, rev...

The combined effect of the use of carbon fiber and seawater and the molecular structure on the tribological behavior of various polymer materials under natural seawater lubrication was investigated. After the investigation, the wear morphology of the contact surface was observed by a laser scanning confocal microscope, and the texture of the wear scars and tracks were presented in 3D profiles. ...

background: some studies have shown that casein phosphopeptide-amorphous calcium phosphate (cpp-acp) and acidulated phosphate fluoride (apf) gel can protect teeth against erosion. the aim of this study was to assess whether cpp-acp and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. materials and methods: enamel specimens consisted o...

statement of problem: as a physical property, wear resistance of the materials used in the fabrication of orthodontic retainers play a significant role in the stability and long term use of the appliances. objectives: to evaluate the wear resistance of two commonly used materials for orthodontic retainers: acropars op, i.e. a polymethyl methacrylate based material, and 3a-gs060, i.e. a polyethy...