AIM To evaluate the cyclic fatigue of Mtwo Ni-Ti rotary instruments after controlled clinical use in molar teeth. METHODOLOGY Twenty Mtwo instruments of each size were selected and divided into two groups: group A consisted of 10 new instruments (control group); group B consisted of 10 used instruments. Each instrument in group B was used to clean and shape 10 root canals of molar teeth in pa...

Malalignment of the tibial tray in total knee arthroplasty has been linked to several complications including tibial tray subsidence, leading to revision surgery. However, quantitative biomechanical evidence to directly support the mechanism of failure is not available. We developed a model to study tibial tray micromotion and subsidence in vitro under multiaxial physiological loading condition...

The purpose of this study was to investigate the relationship between lumbar vertebral microfracture and fatigue loading on young human spine under physiological cyclic compression loads. Thirty-three thoracolumbar vertebrae (T12 to L4) were obtained from 7 adult Chinese male cadavers. They were randomly divided into 5 groups. Cyclical compression was performed for 20,000 cycles with 2 Hz. Load...

In this paper, experimental fatigue behaviour of adhesively bonded PEEK composite was investigated. PEEK based materials are considered as a high performance thermoplastic materials conferring to their good mechanical properties and chemical resistant for many aggressive environments due to their semi-crystallinity property. However, it is well known that the adhesive bonding assembly of this k...

objectives : microbial leakage through the implant-abutment (i-a) interface results in bacterial colonization in two-piece implants. the aim of this study was to compare microleakage rates in three types of replace abutments namely snappy, goldadapt, and customized ceramic using radiotracing. materials and methods: three groups, one for each abutment type, of five implants and one positive and ...

Comparative Evaluation of Cyclic Fatigue Resistance Two Single-file Rotary Instruments in Simulated Stainless Steel Curved Canals

This article presents the strain-based experimental data for Ti-6Al-4V ELI under non-constant amplitude cyclic loading. Uniaxial strain-controlled fatigue experiments were conducted under three different loading conditions, including two-level block loading (i.e. high-low and low-high), periodic overload, and variable amplitude loading. Tests were performed under fully-reversed, and mean strain...

The fatigue behavior of a cellular composite with an epoxy matrix and glass foam granules is analyzed and modeled by means of continuum damage mechanics. The investigated cellular composite is a particular type of composite foam, and is very similar to syntactic foams. In contrast to conventional syntactic foams constituted by hollow spherical particles (balloons), cellular glass, mineral, or m...

The reason of this study is low cycle failure of cast iron cylinder head during the E5 standard durability test. The goal of the present investigation is durability test simulation and low cycle fatigue life evaluation of cast iron cylinder head. With uncouple structural analysis, preloads, thermal and mechanical load and boundary conditions are prescribed to finite element model of the cylinde...

Abstract: In this paper, a systematic numerical simulation was performed to elucidate the damage mechanisms in bulk metallic glasses (BMGs) subjected to the tension-compression cyclic loading, and then the relation between fatigue life, applied strain, and cycling frequency was therefore presented. The free volume was selected as an internal state variable to depict the shear-band nucleation, g...