title: Effect of low-temperature degradation on the mechanical and microstructural properties of tooth-colored 3Y-TZP ceramics.
abstract: The aim of the present study was to evaluate the effects of low-temperature degradation (LTD) induced by autoclaving on the mechanical and microstructural properties of tooth-colored 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP). In total, 162 disc-shaped 3Y-TZP specimens were prepared. Two-thirds of the specimens were shaded by either the infiltration or powder mixing methods while the remaining specimens were used without coloring. The specimens were autoclaved at 134 °C for 0, 10, and 100 h to induce LTD (n=18 for each group). Chemical compositions were analyzed with X-ray fluorescence spectroscopy. Biaxial flexural strength was measured using a piston-on-three-ball test. The surface fraction and penetration depth of the monoclinic phase were examined using X-ray diffraction and scanning electron microscopy, respectively. The tooth-colored 3Y-TZP specimens contained Fe2O3 and Er2O3 (infiltration technique), and Fe2O3 (powder mixing method) at concentrations of<0.5 wt%. The tooth-colored 3Y-TZP had higher strength than the non-colored material after 100 h of autoclaving. In terms of surface fraction and penetration depth, the generation of monoclinic phase was significantly lower in the tooth-colored 3Y-TZP than in the non-colored material. The tooth-colored 3Y-TZP possessed equivalent biaxial flexural strength to that of the non-colored material and higher resistance to LTD regardless of the coloring technique (infiltration technique or powder mixing method) when the coloring pigments were contained at concentrations used in the present study.
authors.affiliation: Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg, Medicinaregatan 12F, Gothenburg 405 30, Sweden; Laboratory for Redox Regulation, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan. Electronic address: keisuke@m.tohoku.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Harada
authors.affiliation: Japan Fine Ceramics Co., Ltd., 3-10, Akedori, Izumi-ku, Sendai 981 3206, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.affiliation: Japan Fine Ceramics Co., Ltd., 3-10, Akedori, Izumi-ku, Sendai 981 3206, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shibasaki
authors.affiliation: Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kanno
authors.affiliation: Laboratory for Redox Regulation, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Niwano
authors.affiliation: Ceramic materials, Swerea IVF, Argongatan 30, Mölndal 431 53, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Adolfsson
authors.affiliation: Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg, Medicinaregatan 12F, Gothenburg 405 30, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Milleding
authors.affiliation: Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg, Medicinaregatan 12F, Gothenburg 405 30, Sweden; Department of Clinical Dentistry/Faculty of Health Sciences, The Arctic University of Norway, Tromsø 9037, Norway.
authors.forename: U
authors.initials: U
authors.lastname: Örtengren
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003116:Color; D004871:Erbium / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D006244:Hardness; D008422:Materials Testing; D055595:Mechanical Phenomena; D010087:Oxides / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014070:Tooth; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D010087:Oxides; C093389:erbium oxide; C000499:ferric oxide; D015019:Yttrium; D004871:Erbium; D015040:Zirconium; C028541:zirconium oxide; C091417:yttria
keywords: Coloring; Low-temperature degradation; Phase transformation; Weibull analysis; Zirconia