To evaluate the influence of cementation on fracture load of anterior crowns made of CAD/CAM-resin-blocks (ART), leucite-reinforced glass-ceramics (LRG), lithium disilicate ceramics (LIT), veneered zirconia (ZRO) and veneered alloy (DEG). Each crown group (n=15/subgroup) was cemented on the metal abutment as follows: i. using glass ionomer, ii. using self-adhesive resin cement, and iii. not cem...

An analysis of chipping fracture in brittle solids is presented. Cracks are introduced into the edges of selected materials, including soda-lime glass and fine-grain ceramics, using a Vickers indenter in monotonic loading. The ensuing chip morphology is examined and shown to exhibit a certain geometrical similarity, independent of material properties. A simple universal relation is derived for ...

Simple relations for the onset of competing brittle and quasiplastic damage modes in Hertzian contact are presented. The formulations are expressed in terms of well-documented material parameters, elastic modulus, toughness, and hardness, enabling a priori predictions for given ceramics and indenter radii. Data from a range of selected ceramic (and other) materials are used to demonstrate the a...

The study describes the acoustic emission (AE) activity during human femur tissue fracture. The specimens were fractured in a bending-torsion loading pattern with concurrent monitoring by two AE sensors. The number of recorded signals correlates well with the applied load providing the onset of micro-fracture at approximately one sixth of the maximum load. Furthermore, waveform frequency conten...

Based on the premise that large-scale failure of sea ice is governed by fracture mechanics, recently validated by Dempsey’s in situ tests of fracture specimens of a record-breaking size, this two-part study applies fracture mechanics and asymptotic approach to obtain approximate explicit formulas for the size effect in two fundamental problems. In the present Part I, the load capacity of a floa...

We consider a nontrivial anti-plane shear fracture problem for a double-crack configuration where the remote external load is applied to the extracted mass-spring chain and the displacement field is symmetric with respect to the central axis between the cracks. An analytical solution obtained for the steady-state problem describes the displacement fields, stresses, local and global energy relea...

A comparative study has been made of human and great ape molar tooth enamel. Nanoindentation techniques are used to map profiles of elastic modulus and hardness across sections from the enamel-dentin junction to the outer tooth surface. The measured data profiles overlap between species, suggesting a degree of commonality in material properties. Using established deformation and fracture relati...

The size effect in the failure of a hybrid adhesive joint of a metal with a fiber-polymer composite, which has been experimentally demonstrated and analytically formulated in preceding two papers, is here investigated numerically. Cohesive finite elements with a mixed-mode fracture criterion are adopted to model the adhesive layer in the metal-composite interface. A linear tractionseparation so...

BACKGROUND Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in the subtrochancteric region has yet to be explored. Therefore, this co...

Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical...