Fatigue strength of yttria-stabilized zirconia polycrystals: Effects of grinding, polishing, glazing, and heat treatment.

Title Fatigue strength of yttria-stabilized zirconia polycrystals: Effects of grinding, polishing, glazing, and heat treatment.
Authors C.Pauleski Zucuni; L.Felipe Guilardi; M.Pivetta Rippe; G.Kalil Roch Pereira; L.Felipe Valandro
Journal J Mech Behav Biomed Mater
DOI 10.1016/j.jmbbm.2017.06.016
Abstract

This study aimed to evaluate and compare the effect of different surface post-processing treatments (polishing, heat treatment, glazing, polishing + heat treatment and polishing + glazing) on the superficial characteristics (micromorphology and roughness), phase transformation and fatigue strength of a Y-TZP ceramic ground with diamond bur. Discs of Y-TZP ceramic were manufactured (ISO:6872-2015; final dimensions of 15mm in diameter and 1.2 ± 0.2mm in thickness) and randomly allocated according to the surface condition: Ctrl - as-sintered; Gr - ground with coarse diamond bur; Gr+HT - ground and subjected to the heat treatment; Gr+Pol - ground and polished; Gr+Pol+HT - ground, polished and heat treated; Gr+Gl - ground and glazed; Gr+Pol+Gl - ground, polished and glazed. The following analyses were performed: roughness (n = 25), surface topography (n = 2), phase transformation (n = 2) and fatigue strength by staircase method (n = 20). All treatments influenced to some extent the surface characteristics of Y-TZP, being that polishing reduced the surface roughness, the m-phase content and improved the fatigue strength; glazing led to the lowest roughness values (Ra and Rz), although it showed the worst fatigue strength; heat treatment showed limited effect on surface roughness, led to complete reversion of the existing m-phase content to t-phase, without enhancing fatigue performance. Thus, a polishing protocol after clinic adjustment (grinding) of monolithic restorations based on polycrystalline zirconia material is mandatory for surface characteristics and fatigue performance improvements.

Citation C.Pauleski Zucuni; L.Felipe Guilardi; M.Pivetta Rippe; G.Kalil Roch Pereira; L.Felipe Valandro.Fatigue strength of yttria-stabilized zirconia polycrystals: Effects of grinding, polishing, glazing, and heat treatment.. J Mech Behav Biomed Mater. 2017;75:512520. doi:10.1016/j.jmbbm.2017.06.016

Related Elements

Yttrium

See more Yttrium products. Yttrium (atomic symbol: Y, atomic number: 39) is a Block D, Group 3, Period 5 element with an atomic weight of 88.90585. Yttrium Bohr ModelThe number of electrons in each of yttrium's shells is [2, 8, 18, 9, 2] and its electron configuration is [Kr] 4d1 5s2. The yttrium atom has a radius of 180 pm and a Van der Waals radius of 219 pm. Yttrium was discovered by Johann Gadolin in 1794 and first isolated by Carl Gustav Mosander in 1840. In its elemental form, Yttrium has a silvery white metallic appearance. Yttrium has the highest thermodynamic affinity for oxygen of any element. Elemental YttriumYttrium is not found in nature as a free element and is almost always found combined with the lanthanides in rare earth minerals. While not part of the rare earth series, it resembles the heavy rare earths which are sometimes referred to as the "yttrics" for this reason. Another unique characteristic derives from its ability to form crystals with useful properties. The name yttrium originated from a Swedish village near Vaxholm called Yttbery where it was discovered.

Zirconium

See more Zirconium products. Zirconium (atomic symbol: Zr, atomic number: 40) is a Block D, Group 4, Period 5 element with an atomic weight of 91.224. Zirconium Bohr ModelThe number of electrons in each of Zirconium's shells is 2, 8, 18, 10, 2 and its electron configuration is [Kr]4d2 5s2. The zirconium atom has a radius of 160 pm and a Van der Waals radius of 186 pm. Zirconium was discovered by Martin Heinrich Klaproth in 1789 and first isolated by Jöns Jakob Berzelius in 1824. In its elemental form, zirconium has a silvery white appearance that is similar to titanium. Zirconium's principal mineral is zircon (zirconium silicate). Elemental ZirconiumZirconium is commercially produced as a byproduct of titanium and tin mining and has many applications as a opacifier and a refractory material. It is not found in nature as a free element. The name of zirconium comes from the mineral zircon, the most important source of zirconium, and from the Persian wordzargun, meaning gold-like.

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