This review presents a critical survey of all experimental data about the low temperature degradation of zirconia (often referred to as "aging") due to the tetragonal-to-monoclinic transformation, which have been collected at temperatures of interest for dental application (room temperature to about 100 degrees C). It is shown that the main factors affecting the aging phenomenon are (i) the sta...

aluminum sulfate nano structures have been prepared by solution combustion synthesis using aluminum nitrate nonahydrate (al(no3)3.9h2o) and ammonium sulfate ((nh4)2so4). the resultant aluminum sulfate nano structures were calcined at different temperatures to study thermal  decomposition of aluminum sulfate. the crystallinity and phase of  the as-synthesized and calcined samples were characteri...

Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 microm average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6 +/- 1.9 microm average grain size and 72 vol% porosity and 588 +/- 55nm average grain size, respectively. Scanning electron microscopy was used to ...

The purpose of this study is to evaluate the fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia. Commercial semi-sintered zirconia, sintered dense zirconia and sintered hybrid zirconia were used. Sintered zirconia was milled using the CAD/CAM system, and semi-sintered zirconia was milled and sintered to fabricate molar crown f...

During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and ve...

Veneer cracking or chipping is the major complication of the zirconia based restorations. Monolithic zirconia has been introduced to overcome this problem, as well as to use in patients with limited interocclusal space. Many research articles on monolithic zirconia crowns have been published in the last years. The aim of this review article was to present data about the wear, surface roughness,...

Abstract Meteorite impact processes are ubiquitous on the surfaces of rocky and icy bodies in Solar System, including Moon. One most common accessory minerals, zircon, when shocked, produces specific micro-structures that may become indicative age shock conditions these processes. To better understand mechanisms zircon from Apollo 15 16 breccias, we applied transmission electron microscopy (TEM...