Fatigue fractures of the femoral component of cementless hip prostheses are rare occurrences at present, but may become more widespread in the future as the demand increases for porous coated cementless hip arthroplasty in young, active, and heavy patients. Whereas the fatigue fracture of high strength forged alloys is unlikely, a risk of fatigue fracture may exist for sintered porous coated st...

INTRODUCTION The use of reciprocating movement was claimed to increase the resistance of nickel-titanium (NiTi) file to fatigue in comparison with continuous rotation. Recently 2 new brands of NiTi files have been marketed for use in a RM mode. The purpose of this study was to compare the cyclic fatigue resistance and torsional resistance of these 2 files, Reciproc and WaveOne. METHODS Cyclic...

In this paper, the fatigue and fracture properties of bovine dentin are evaluated using in vitro experimental analyses. Double cantilever beam (DCB) specimens were prepared from bovine maxillary molars and subjected to zeroto-tension cyclic loads. The fatigue crack growth rate was evaluated as a function of the dentin tubule orientation using the Paris law. Wedge-loaded DCB specimens were also ...

PURPOSE To investigate the effect of reducing tooth preparation and ceramic thickness on fracture resistance of lithium disilicate crowns. MATERIALS AND METHODS Specimen preparation included a standard complete crown preparation of a typodont mandibular left first molar with an occlusal reduction of 2 mm, proximal/axial wall reduction of 1.5 mm, and 1.0 mm deep chamfer (Group A). Another typo...

The fatigue cracks are observed in asphalt surfaces much more than ruts. This paper deals with the influence of carbon nano-tube on the fatigue life of asphalt mixtures. These samples are made up of the slabs cut by the asphalt cutting saw. Fatigue beams contain 0, 0.3, 0.6, 0.9, 1.2, and 1.5 percent of Carbon Nano-tube. The fatigue experiment was conducted using a 4-point semi-sinusoidal loadi...

This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary files with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Gro...

BACKGROUND/PURPOSE Dental rotary instruments can be applied in multiple conditions of canals, but unpredictable fatigue fracture may happen. This study evaluated the fatigue lives of two batches of nickel-titanium (NiTi) dental rotary files operating in clinically simulated root canals. METHODS Single-step cyclic fatigue tests were carried out to assess the performance of two batches of NiTi ...

A procedure to predict the fatigue fracture life of high-heat-load components made of GlidCop has been successfully established. This method is based upon the Manson-Coffin equation with a cumulative linear damage law. This prediction was achieved by consolidating the results of experiments and analyses, and considered the effects of environment and creep. A low-cycle-fatigue test for GlidCop w...

Crack initiation and growth behaviour of an austempered ductile iron (ADI) austenitised at 800C and austempered at 260C has been assessed under three point bend fatigue conditions. Initiation sites have been identified as carbides remaining from the as cast ductile iron due to insufficient austenisation. The number of carbides cracking on loading to stresses greater than 275 MPa is critical in ...

Abstract: The high cycle fatigue property of carburized 20Cr gear steel was experimentally investigated under axial loading with a stress ratio of zero. The test results show that this steel exhibits gradually decreasing S-N characteristics, and the fatigue strength corresponding to 109 cycles is about 455 MPa. Based on the observation of fracture surfaces, the interior inclusion fisheye-induce...