title: Biaxial flexure strength and low temperature degradation of Ce-TZP/Al2O3 nanocomposite and Y-TZP as dental restoratives.
abstract: The purpose of the present study was to evaluate the mechanical durability of a zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al(2)O(3) nanocomposite) in comparison to yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and discuss its application on ceramic dental restorations. The disk-shaped specimens of both materials were stored in physiological saline solution at 80 degrees C for 30 days, in 4% acetic acid at 80 degrees C for 30 days, and in an autoclave at 121 degrees C for 10 days. Before and after storage, specimens were subjected to the biaxial flexure test and to the determination of the monoclinic zirconia content. After autoclaving, Y-TZP showed remarkable increasing of the content of monoclinic zirconia: 0.3 vol % before and 49.9 vol % after, and slight decreasing of biaxial flexure strength: 1046 MPa before and 892 MPa after; whereas Ce-TZP/Al(2)O(3) nanocomposite showed no significant difference in the monoclinic content (4.8-5.5 vol %) and the biaxial flexure strength (1371-1422 MPa) after storage in any conditions. It is concluded that, compared to Y-TZP, the Ce-TZP/Al(2)O(3) nanocomposite has a high biaxial flexure strength along with a satisfactory durability in terms of low-temperature aging degradation in above conditions. This study indicates that the Ce-TZP/Al(2)O(3) nanocomposite demonstrates excellent mechanical durability for dental restorations such as all-ceramic bridges.
authors.affiliation: Department of Biomaterials Science, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-0145, Japan. sban@denta.hal.kagoshima-u.ac.jp
authors.forename: Seiji
authors.initials: S
authors.lastname: Ban
authors.forename: Hideo
authors.initials: H
authors.lastname: Sato
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Suehiro
authors.forename: Hideo
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nawa
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry*; D003460:Crystallization; D003764:Dental Materials / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry*; D013314:Stress, Mechanical; D013696:Temperature; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D002586:Cesium; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide