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.

Surface damages of zirconia by Nd:YAG dental laser irradiation

“…Disappearance of alumina phase In the present study, the Ce-TZP/Al2O3 nanocomposite was composed of 10 mol% CeO2 stabilized TZP as a matrix and 30 vol% of Al2O3 as a second phase. In our previous study 6) , it was reported that the average grain size of both phases was 0.49±0.12 µm. After a separate determination of each phase, the grain sizes of Ce-TZP and Al2O3 were 0.59±0.09 µm and 0.42±0.08 µm Table 1 Average X-ray intensity ratios of oxygen, zirconium, yttrium, hafnium, aluminum, and cerium in the irradiated pits to the surface composition without irradiation respectively.…”

“…For improved mechanical strength, a ceriastabilized zirconia/alumina nanocomposite (Ce-TZP/ Al2O3 nanocomposite) was developed 3) . Previously, we demonstrated that, in comparison with Y-TZP, the Ce-TZP/Al2O3 nanocomposite exhibited a higher flexural strength and toughness, coupled with satisfactory durability, when exposed to low-temperature aging degradation in the various aqueous environments commonly encountered in dentistry [4][5][6] . Prosthetic devices are often complex in shape.…”

The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio

“…The tetragonal form for metastable zirconia in biomedical applications could be achieved at room temperature by alloying zirconia with other oxides (stabilizers), e.g. CaO [3], MgO [4], Y 2 O 3 [5][6][7][8] and CeO 2 [9]. Y 2 O 3 (approximately 3 mol%) is the most widely used stabilizer for dental zirconia (Y-TZP) [2].…”

Effect of Small Amount of Insoluble Dopant on Tetragonal to Monoclinic Phase Transformation in Tetragonal Zirconia Polycrystal

“…Moreover, many dental application of zirconia has been developed. 4,5) 3 mol%Y 2 O 3 stabilized tetragonal zirconia polycrystal (3Y-TZP) is the most popular material in such zirconia bioceramics, but some composites or doped-materials are also used in recent years. For example, alumina-dispersed ceria stabilized TZP with small amount of titania is developed in dental application.…”

“…For example, alumina-dispersed ceria stabilized TZP with small amount of titania is developed in dental application. 5) We have also developed an insert material for joining of zirconia dental bridge with a composition of 7.7 mol%TiO 2 -doped TZP, 6,7) by applying enhanced superplasticity in TiO 2 -doped TZP explained from the balance between the grain size and the increased accommodation length for the stress concentration by diffusion. [8][9][10] Thus, it is important to investigate the effect of second phase or dopant on some properties in zirconia bioceramics.…”