DENTAL MATERIALS 24(2008)289-298 availableatwww.sciencedirect.com materials ° Science Direct ElseVierjournalhomepagewww.intl.elsevierhealth.com/journals/dema Systematic review article Stabilized zirconia as a structural ceramic. an overview J. Robert Kelly a,, Isabelle Denry Department of Reconstructive Sciences, Center for Biomaterials, University of Connecticut Health Center, Farmington, CT USA b Department of Restorative and Prosthetic Dentistry, The Ohio State University, Columbus, OH USA ARTICLE INFO A BSTRACT This review introduces concepts and background from the ceramics engineering literature Received 24 April 2007 regarding metastable zirconia ceramics to establish a context for understanding current and Accepted 11 May 2007 emerging zirconia-based dental ceramics e 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. Zirconia ramiCs Dental ceramics ghening Stabilized tetragonal R-curve Dispersion-toughened zirconia Partially stabilized zirconia Toughened zirconia polycrystalline Y-TZP 1. Toward improved reliability: (1)flaw control and(2)flaw tolerance 2. Zirconia polymorphs: temperature dependence and transformation strains 3. Three distinct zirconia ceramics: terminology, processing and microstructures 3.1 rtially stabilized zi 3.3. Single-phase, polycrystalline t-zro2 4. Mechanism(s) and consequences of transformation 293 5. R-curve behavior: description, definition and implications 6. Strength versus toughness Cyclic fatigue of transformation-toughened ceramics Presentend nt the annua cessio hef th cecnatde ms f ental Materias, e Etobein 2t55 06 30 1615. sa Tll fax:+18606791370 E-mail address: Kelly@nsol. uchc. edu .R Kelly) 0109-5641/$-see front matter e 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. doi:10.1016/ denta2007.05005dental materials 24 (2008) 289–298 available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/dema Systematic review article Stabilized zirconia as a structural ceramic: An overview J. Robert Kelly a,∗, Isabelle Denry b a Department of Reconstructive Sciences, Center for Biomaterials, University of Connecticut Health Center, Farmington, CT USA b Department of Restorative and Prosthetic Dentistry, The Ohio State University, Columbus, OH USA article info Article history: Received 24 April 2007 Accepted 11 May 2007 Keywords: Zirconia Ceramics Dental ceramics Transformation toughening Stabilized tetragonal R-curve Dispersion-toughened zirconia Partially stabilized zirconia Toughened zirconia polycrystalline Y-TZP abstract This review introduces concepts and background from the ceramics engineering literature regarding metastable zirconia ceramics to establish a context for understanding current and emerging zirconia-based dental ceramics. © 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. Contents 1. Toward improved reliability: (1) flaw control and (2) flaw tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 2. Zirconia polymorphs: temperature dependence and transformation strains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 3. Three distinct zirconia ceramics: terminology, processing and microstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 3.1. Dispersion-toughened ceramics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 3.2. Partially stabilized zirconia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 3.3. Single-phase, polycrystalline t-ZrO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 4. Mechanism(s) and consequences of transformation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 5. R-curve behavior: description, definition and implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 6. Strength versus toughness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 7. Cyclic fatigue of transformation-toughened ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 Presented at the annual session of the Academy of Dental Materials, October 23–25, 2006, Sao Paulo, Brazil. ˜ ∗ Corresponding author at: UConn Health Center, 263 Farmington Avenue, Farmington, CT 06030-1615, USA. Tel.: +1 860 679 3747; fax: +1 860 679 1370. E-mail address: Kelly@nso1.uchc.edu (J.R. Kelly). 0109-5641/$ – see front matter © 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.dental.2007.05.005