background : in anterior endodontically treated teeth a better esthetic can be achieved by using all-ceramic post -core restorations instead of metal post systems. maximum retention and fracture resistance of the post are the criteria upon which selection of a post system is based. the aim of this study was to evaluate the fracture resistance and retention of two all-ceramic post and core syste...

statement of problem: endodontically treated teeth are more prone to fracture. the post and core are often used to provide the necessary retention for prosthetic rehabilitation. objectives: the purpose of this study was to: 1) compare the fracture strength of endodontically treated teeth restored either with nickel-chromium (ni- cr) post or non- precious gold-color alloy (npg) post compared to ...

This article provides a fully analytical approach for nonlinear equilibrium path of rectangular sandwich plates. The core of structure is made of symmetric cross-ply laminated composite and the outer surfaces are piezoelectric actuators which perfectly bonded to inner core. The structure is subjected to electro-thermo-mechanical loads simultaneously. One side of plate is rested on Pasternak typ...

A two-center three-electron 2c-3e bond (hemi-bond) is a non-classical chemical bond, and its existence has been supposed in radical cation clusters with lone pairs. Though the nature of the hemi-bond and its role in the reactivity of radical cations have attracted great interest, spectroscopic observations of hemi-bonded structures have been very scarce. In the present study, the presence of a ...

OBJECTIVES To investigate the effectiveness of two restorative materials for reinforcing thin-walled roots and their microtensile bond strengths to root canal dentin. METHODS Twenty-one decoronated maxillary central incisor roots were root filled and the canals enlarged to leave approximately 1.0 mm thick dentin walls. The roots were distributed randomly to three equal groups. Group 1 (contro...