Strength, fracture toughness and microstructure of a selection of all-ceramic materials. Part II. Zirconia-based dental ceramics.
TL;DR: Microscope investigation and X-ray diffraction revealed the important role played by the tetragonal to monoclinic phase transformation and by the relationship between the glassy matrix and the crystalline phase in the strengthening and toughening mechanisms of these ceramics.
About: This article is published in Dental Materials.The article was published on 2004-06-01. It has received 828 citations till now. The article focuses on the topics: Yttria-stabilized zirconia & Fracture toughness.
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University of Cambridge1, Istituto Italiano di Tecnologia2, Lancaster University3, University of Manchester4, Catalan Institution for Research and Advanced Studies5, Technical University of Denmark6, Nokia7, fondazione bruno kessler8, University of Trento9, Queen Mary University of London10, Technische Universität München11, Polytechnic University of Milan12, Centre national de la recherche scientifique13, University of Trieste14, University of Ioannina15, University of Geneva16, Trinity College, Dublin17, Texas Instruments18, University of Paris19, Spanish National Research Council20, Leiden University21, Delft University of Technology22, University of Patras23, École Normale Supérieure24, Radboud University Nijmegen25, Nest Labs26, Airbus UK27, Seoul National University28, Yonsei University29, University of Oxford30, Chalmers University of Technology31, University of Groningen32, STMicroelectronics33, Chemnitz University of Technology34, Max Planck Society35, Aalto University36
TL;DR: An overview of the key aspects of graphene and related materials, ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries are provided.
Abstract: We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
2,560 citations
TL;DR: The two main processing techniques, soft and hard machining, are assessed in the light of their possible clinical implications and consequences on the long-term performance of zirconia.
1,696 citations
Cites background from "Strength, fracture toughness and mi..."
...In contrast, restorations produced by hard machining of fully sintered 3Y-TZP blocks have been shown to contain a significant amount of monoclinic zirconia [26]....
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...5 m in diameter, depending on the sintering temperature) [26]....
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...This partially explains the generally lower mechanical properties of In-Ceram® Zirconia® when compared to 3Y-TZP dental ceramics [26]....
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...[26] Guazzato M, Albakry M, Ringer SP, Swain MV....
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TL;DR: It is demonstrated that highly polished zirconia yielded lower antagonist wear compared with porcelains, and combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is currently one of the most reliable bonding systems for zirConia.
529 citations
Cites background from "Strength, fracture toughness and mi..."
...Ce-TZP/A is the toughest dental ceramic material available, with a fracture toughness of 19 MPa m1/2, and a flexural strength of 1400 MPa [12]....
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...Although there have not been many reports [42–44] concerning the evaluation of zirconia-to-porcelain integration using a bending test (ISO9693), all of those reported that the bond strength was 25 MPa or more....
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...Conventional porcelain is a partially glassy material; its fracture toughness is approximately 1.0 MPa m1/ 2 and flexural strength is approximately 100 MPa....
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...Y-TZP has a high fracture toughness, from 5 to 10 MPa m1/2, and a flexural strength of 900– 1400 MPa [8,9]....
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...Ceria-stabilized tetragonal zirconia polycrystalline (CeTZP) showed much higher fracture toughness of 19 MPa m1/ 2 but lower flexural strength and hardness than Y-TZP....
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TL;DR: The present study suggests that sandblasting and grinding may be recommended to increase the strength of dental Y-TZP, provided they are not followed by heat treatment.
457 citations
TL;DR: The central argument of this study is that residual stresses developed during the preparation of all-ceramic crowns and fixed partial dentures coupled with contact-induced cracking are the origin of the excessive chipping observed in clinical applications.
456 citations
References
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TL;DR: A review of fracture mechanics in structural ceramics can be found in this paper, where the authors provide a perspective regarding the evolution of this field and succinct descriptions of current understanding.
Abstract: The science governing the strength and fracture of structural ceramics has developed from a mostly empirical topic in 1965 into a mature discipline that now sets the standards in the field of mechanical behavior. The intent of this review is to provide a perspective regarding this evolution, followed by succinct descriptions of current understanding. The rapid developments in the field are considered to have commenced upon the first concerted attempt to apply fracture mechanics concepts to ceramics, beginning in the middle 1960s. This allowed a distinction between the separate contributions to strength from the flaws in the material and from the microstructure, as manifest in the fracture toughness. Another contribution that accelerated the learning process was the development of indentation techniques, which allowed trends in the damage resistance of new ceramics to be assessed on a routine basis. However, the most important development, which originated at about the same time, was the discovery of toughened zirconia alloys. The ensuing research on these alloys established two vital precedents.
1,462 citations
TL;DR: In this article, the content of free ZrO2 in partially stabilized zirconia ceramics by X-ray diffraction techniques was determined by linear calibration curves.
Abstract: Linear calibration curves were developed for determining the content of free ZrO2 in partially stabilized zirconia ceramics by X-ray diffraction techniques. Two methods were studied. The matrix method, in which free ZrO2 was considered to be distributed in a matrix (the cubic phase), gave approximately equal mass absorption coefficients for the monoclinic and cubic phases. The polymorph technique, in which the cubic phase was considered to be a polymorph of ZrO2 and in which integrated intensities were used, gave the better results.
1,302 citations
"Strength, fracture toughness and mi..." refers methods in this paper
...The relative amount ðXMÞ of the monoclinic phase was calculated as suggested by Garvie and Nicholson.(17)...
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...The relative amount ðXMÞ of the monoclinic phase was calculated as suggested by Garvie and Nicholson.17...
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TL;DR: In this paper, the sharp-indentation technique of strength-test precracking for toughness evaluation is examined and the residual-stress term discussed in Part I of this study is now introduced explicitly into the strength formulation.
Abstract: An examination is made of the sharp-indentation technique of strength-test precracking for toughness evaluation. The experimental approach follows that proposed by other workers but the theoretical analysis contains one vital new feature; the residual-stress term discussed in Part I of this study is now introduced explicitly into the strength formulation. This modification overcomes a major systematic discrepancy evident in the previous models and at the same time, by virtue of attendant changes in the nature of the crack stability prior to attaining a failure configuration, eliminates the need for frac-tographic measurements. Other advantages are also apparent, notably an insensitivity to postindentation radial crack extension. The main disadvantage is that only one result is obtained per specimen. Indentation/strength data from ceramics listed in Part I confirm the essential features of the theory and provide a suitable calibration factor. The method has special application to those materials which do not necessarily produce a well-defined radial crack pattern, in which case an “effective”Kc appropriate to fracture properties at the flaw level is obtained.
1,146 citations
TL;DR: Comparing three hot-pressed glass-ceramics and alumina glass-infiltrated ceramics, processed by both slip casting and dry pressing, revealed the relationship between the glass matrix and the crystalline phase and the characteristics of the latter were correlated to the strengthening and toughening mechanisms of these glass- Aceramics.
451 citations
"Strength, fracture toughness and mi..." refers background or methods in this paper
...The present paper focuses on IZ slip, IZ dry-pressed, DZ and YZ and compares these ceramics to peer materials already discussed in part I.(11)...
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...1) are very similar and resemble that of IA slip as described in part I.(11) Although the values of tensile strength (Table 1) may induce one to associate IA Figure 2 Micrographs of fully sintered zirconias....
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...Strength was measured with a three-point bending technique as described in part I and reported by ISO 6872.(11,12) M....
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TL;DR: Both tetragonal (t) and monoclinic (m) ZrO2 particles in Al2O3 can give rise to toughening, and the residual stresses around already-transformed m-ZrO 2 particles can cause microcracking as discussed by the authors.
Abstract: Both tetragonal (t) and monoclinic (m) ZrO2 particles in ZrO2-toughened Al2O3 can give rise to toughening. In the stress field of propagating cracks, the t-ZrO2 particles can undergo the stress-induced t→m transformation, and the residual stresses around already-transformed m-ZrO2 particles can cause microcracking. The t-ZrO2 particles transformed in crack tip stress fields do not, however, also cause appreciable microcracking. The toughening increments via these distinct mechanisms are comparable. It appears that optimally fabricated Zr02-toughened Al2O3's should contain a mixture of t- and m-ZrO2.
225 citations