Strength and aging resistance of monolithic zirconia: an update to current knowledge

Abstract

New zirconia compositions with optimized esthetic properties have emerged due to the fast-growing technology in zirconia manufacturing. However, the large variety of commercial products and synthesis routes, make impossible to include all of them under the general term of “monolithic zirconia ceramics”. Ultra- or high translucent monolithic formulations contain 3–8 mol% yttria, which results in materials with completely different structure, optical and mechanical properties. The purpose of this study was to provide an update to the current knowledge concerning monolithic zirconia and to review factors related to strength and aging resistance. Factors such as composition, coloring procedures, sintering method and temperature, may affect both strength and aging resistance to a more or less extend. A significant reduction of mechanical properties has been correlated to high translucent zirconia formualtions while regarding aging resistance, the findings are contradictory, necessitating more and thorough investigation. Despite the obvious advantages of contemporary monolithic zirconia ceramics, further scientific evidence is required that will eventually lead to the appropriate laboratory and clinical guidelines for their use. Until then, a safe suggestion should be to utilize high-strength partially-stabilized zirconia for posterior or long span restorations and fully-stabilized ultra-translucent zirconia for anterior single crowns and short span fixed partial dentures.

Influence of Occlusal Thickness and Radicular Extension on the Fracture Resistance of Premolar Endocrowns from Different All-Ceramic Materials

“…The flexural strength and modulus of elasticity of HTZ zirconia is reported to be at 800-1100 MPa and 200 GPa. The HTZ has more natural esthetic properties with increased optical properties attributed to the inclusion of cubic zirconia [49]. Several studies concluded the lower mechanical properties of HTZ ceramic is due to the absence of transformation toughening mechanism [50].…”

Bioactive Glass Coated Zirconia for Dental Implants: a review

“…Their biological inertness and electrical passivation have made ceramics a promising material in the medical equipment and medicine. In comparison with metallic implants, zirconia-based ceramics show minimum ion release and are biologically inert [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Modern Ti implant technologies are being introduced due to possible combination of immunologic and aesthetic aspects of Ti and Ti alloys.…”

An experimental study on hydrothermal degradation of cubic-containing translucent zirconia

“… 5 6 7 8 9 10 Increasing amount of Y 2 O 3 stabilizer tends to alter the phase structure from tetragonal to cubic phase resulting in increased translucency and improved hydrothermal aging resistance. 11 12 13 14 The amount of cubic crystal structures seems to have an effect on the microstructure of zirconia materials, 15 particularly mechanical properties. 14 Nowadays, the studies have reported that increasing amount of cubic phase in zirconia can improve translucency of cubic-containing zirconia compared to conventional zirconia.…”

“… 11 12 13 14 The amount of cubic crystal structures seems to have an effect on the microstructure of zirconia materials, 15 particularly mechanical properties. 14 Nowadays, the studies have reported that increasing amount of cubic phase in zirconia can improve translucency of cubic-containing zirconia compared to conventional zirconia. 12 14 16 However, limited numbers of studies are available regarding the mechanical properties and degradation behavior of cubic zirconia for monolithic restorations.…”