A comparison of fracture strength of yttrium‐oxide‐ partially‐stabilized zirconia ceramic crowns with varying core thickness, shapes and veneer ceramics

Abstract

The fracture strengths of stylized all-ceramic crowns manufactured using an yttrium-oxide-partially-stabilized (Y-TZP) zirconia ceramic core (Denzir) veneered with lithium disilicate glass-ceramics (IPS Empress 2 or IPS Eris) were evaluated. The Denzir cores were manufactured in two ways: either with different thickness in different parts of the restoration, called an 'adapted Denzir core'; or with a uniform core thickness of 0.5 mm. IPS Empress 2 all-ceramic crowns served as reference. There was no significant difference between the crowns with an 'adapted Denzir core' veneered with the two brands of glass-ceramics. No significant difference was seen between the crowns with a 0.5 mm Denzir core veneered with the two brands of glass-ceramics. The crowns with an 'adapted Denzir core' exhibited significantly higher values than those with a 0.5 mm Denzir core and than the IPS Empress 2 crowns used as reference. No significant differences were seen among the IPS Empress 2 crowns used as reference and the crowns with a 0.5 mm Denzir core. The mode of failure varied among the Empress 2 crowns and the crowns with a core of a Y-TZP zirconia ceramic. Long-term studies are necessary to assess the clinical performance of this restorative system.

Influence of core thickness and artificial aging on the biaxial flexural strength of different all-ceramic materials: An <i>in-vitro</i> study

“…In recent studies it has been reported that there is a correlation between the thickness of the core/ veneer ceramics and the flexural strength 7,22,24,39) . On the other hand, Thompson et al 40) , in a fractographic study of clinically failed crowns, concluded that fracture initiation sites of dental ceramics are controlled primarily by the location and size of the critical flaw and not by specimen thickness.…”

“…Clinically, an appropriate strength characteristics is an important aspect of dental restoration. According to previous studies, the long-term strength properties of all-ceramic restorations depend upon several factors, such as fabrication type [14][15][16][17] , laboratory procedures [18][19][20][21] , core or veneer thickness 4,7,22) , fatique resistance 23) , luting procedure 24,25) , and aging 11,14,[26][27][28] . Thus, it is important to determine the mechanical behavior of this category of dental materials in vitro.…”

Wear performance of bovine tooth enamel against translucent tetragonal zirconia polycrystals after different surface treatments

“…The bonding mechanism between Y-TZP and the veneering ceramics is not well known, and the core-veneer interface is among the weakest aspects of these restorations even though the firm bonding of the veneering porcelain to the TZP substrate is recognized 1,2) . In in vitro studies of layered zirconia crowns, the fracture strength was mostly limited to the veneering ceramics 3) . In clinical applications, the veneering ceramics has also been shown to be the weakest link in zirconia-supported reconstructions 1) .…”

Effect of Three Veneering Techniques on Marginal Accuracy and Fracture Resistance of Zirconia Base Fixed Restoration (In-Vitro Study).

“…The die material used during fracture resistance testing was either cobalt chromium 4 .,Titanium 6 , stainless steel 8,10,11 , natural teeth 12 and inlay pattern resin 9 Ideally it should have been epoxy resin to simulate the modulus of elasticity of the natural teeth.…”