AIM The aim of this study was to investigate the fracture resistance of two types of ceramic crowns cemented with two different cements. METHODS AND MATERIALS Forty premolar crowns were fabricated using lithium-disilicate (IPS Empress-2) and glass-infiltrated aluminium-oxide (In-Ceram) ceramic systems. The crowns were divided into four groups (n=10) with Group 1 (IPS Empress-2) and Group 2 (I...

BACKGROUND A variety of methods are available for the fixation of femoral shaft fractures after total hip arthroplasty. However, few studies in the literature have quantified the performance of such repair constructs. The aim of this study was to evaluate biomechanically four different constructs for the fixation of periprosthetic femoral shaft fractures following total hip arthroplasty. METH...

Purpose The aim of this study was to describe different designs of semimonolithic crowns made of translucent and high-translucent zirconia materials and to evaluate the effect on fracture resistance and fracture mode. Methods One hundred crowns with different designs were produced and divided into five groups (n=20): monolithic (M), partially veneered monolithic (semimonolithic) with 0.3 mm b...

We describe the historical development of large-scale nonequilibrium molecular-dynamics (NEMD) computer simulations of fracture at Los Alamos. We have found that dynamic crack propagation leads to energy buildup that seeds instabilities, such as dislocation emission and branching. Recent three-dimensional simulations have shed light on ductile fracture mechanisms, including sequences of disloca...

The fracture modes of hydroxyapatite (HA) scaffolds fabricated by direct-write assembly (robocasting) are analyzed in this work. Concentrated HA inks with suitable viscoelastic properties were developed to enable the fabrication of prototype structures consisting of a 3-D square mesh of interpenetrating rods. The fracture behavior of these model scaffolds under compressive stresses is determine...

We subjected the time series of quasi-rigid-body vibration pulses (elastic emissions) from laboratory fracture carried out by a piezoelectric accelerometer on concrete and rock specimens under uniaxial compression to statistical analysis. In both cases, we find that the waiting-time distribution can be described by a scaling law extending over several orders of magnitude. This law is indistingu...

The penetration of a projectile into warship broadside liquid cabin is usually non-ideal process. To explore the protective effects large against rod projectiles and to provide reference for design new structures, ballistic impact tests penetrating at different attack angles were carried out. Combined with numerical calculation, angle on water entry characteristics as well their failure modes s...

Background and Aim: Different methods and materials are available for post and core (P&C) fabrication. We aimed to compare the fracture resistance and failure modes of endodontically treated maxillary central incisors restored with six different P&C systems. Materials and Methods: In this in-vitro study, after endodontic treatment and coronal preparation of 60 maxillary central incisors, six d...

By partitioning the total stresses in a damaged composite into either mechanical and residual stresses or into initial and perturbation stresses, it was possible to derive two exact results for the energy release rate due to crack growth. These general results automatically include the effects of residual stresses, tractionloaded cracks, and imperfect interfaces. These effects are normally not ...

In situ fracture study of a Cu/Al composite laminate was discussed via the observation of scanning electron microscope (SEM). The experimental test was carried out by a modified miniature tensile device. With the aid of the SEM’s sample stage and a wedge block, the profile morphology of the specimen was observed. The substrate layer (1060 aluminum) and the plate layer (C11000 copper) of the spe...