OBJECTIVE This study evaluated the influence of porcelain (VM9, VITA Zahnfabrik, Germany) thickness on the flexural strength and crack propagation in bilayered zirconia systems (YZ, VITA Zahnfabrik, Germany). MATERIAL AND METHODS Thirty zirconia bars (20.0x4.0x1.0 mm) and six zirconia blocks (12.0x7.5x1.2 mm) were prepared and veneered with porcelain with different thickness: 1 mm, 2 mm, or 3...

La-doped zirconia films, deposited by ALD at 300°C, were found to be amorphous with dielectric constants (k-values) up to 19. A tetragonal or cubic phase was induced by post-deposition annealing (PDA) at 900°C in both nitrogen and air. Higher k-values (~32) were measured following PDA in air, but not after PDA in nitrogen. However, a significant dielectric relaxation was observed in the air-ann...

The present work focuses on the mechanochemical preparation of industrially important β-cyclodextrin (CD) derivatives. Activated CDs have been reacted with nitrogen and sulfur nucleophiles using a planetary mill equipped with stainless steel, zirconia and glass milling tools of different sizes. It is shown that the milling frequency and the number as well as the size of the milling balls have a...

OBJECTIVES To observe porcelain veneer behavior of zirconia and metal-ceramic full coverage crowns when subjected to compression testing, comparing zirconia cores to metal cores. STUDY DESIGN The porcelain fracture surfaces of 120 full coverage crowns (60 with a metal core and 60 with a zirconia core) subjected to static load (compression) testing were analyzed. Image analysis was performed u...

The effect of an additive 0.5 wt. % zirconium oxide on the spark plasma sintering (SPS) kinetics alumina powders has been studied. Ceramics were obtained by mixing in a planetary mill with grinding media from stabilized oxide. activation energy SPS was estimated using Young-Cutler model. It shown that density and average grain size ceramics submicron are significantly affected nonequilibrium st...