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Strength and aging resistance of monolithic zirconia: an update to current knowledge

Eleana kontonasaki, panagiotis giasimakopoulos, athanasios e rigos.

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Corresponding author at: Laboratory of Prosthodontics, Department of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece. [email protected]

Received 2019 May 20; Revised 2019 Aug 2; Accepted 2019 Sep 17; Issue date 2020 Nov.

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

New zirconia compositions with optimized esthetic properties have emerged due to the fast-growing technology in zirconia manufacturing. However, the large variety of commercial products and synthesis routes, make impossible to include all of them under the general term of “monolithic zirconia ceramics”. Ultra- or high translucent monolithic formulations contain 3–8 mol% yttria, which results in materials with completely different structure, optical and mechanical properties. The purpose of this study was to provide an update to the current knowledge concerning monolithic zirconia and to review factors related to strength and aging resistance. Factors such as composition, coloring procedures, sintering method and temperature, may affect both strength and aging resistance to a more or less extend. A significant reduction of mechanical properties has been correlated to high translucent zirconia formualtions while regarding aging resistance, the findings are contradictory, necessitating more and thorough investigation. Despite the obvious advantages of contemporary monolithic zirconia ceramics, further scientific evidence is required that will eventually lead to the appropriate laboratory and clinical guidelines for their use. Until then, a safe suggestion should be to utilize high-strength partially-stabilized zirconia for posterior or long span restorations and fully-stabilized ultra-translucent zirconia for anterior single crowns and short span fixed partial dentures.

Keywords: Monolithic zirconia ceramics, Strength, Aging

1. Introduction

Zirconia was suggested as the first candidate for full contour monolithic restorations due to its significant advantages, such as excellent mechanical properties, superior to those of other ceramic systems, esthetic performance comparable to that of metal-ceramic restorations, radiopacity, low corrosion potential, good chemical properties, volumetric stability and elastic modulus values comparable to steel [ [1] , [2] , [3] , [4] , [5] , [6] ]. According to in-vitro studies, zirconia restorations exhibit flexural or bending strength values of 900–1200 MPa and resistance to fracture of 9–10 MPa [ 7 ]. However, zirconia ceramics do suffer from low-temperature degradation (LTD), also known as aging [ 8 ]. In particular, the spontaneous and progressive transformation of the tetragonal phase to monoclinic degrades the mechanical properties of the Y-TZP and, in particular, its strength. Specific processing conditions, environmental humidity, stress and temperatures between 200–300 °C may accelerate it [ 5 , [8] , [9] , [10] ]. Many experimental studies have shown that water molecules can penetrate the zirconia structure when exposed to a hygroscopic environment. The triatomic character of yttrium contributes to the presence of several oxygen vacancies in the zirconia lattice, which facilitates the diffusion of water molecules into its mass [ 8 ]. The diffusion of water initially causes a lattice contraction that will result in tensile stresses’ concentration on the surface of the zirconia grains resulting in the transformation of the tetragonal phase to monoclinic phase. The increase in volume, that accompanies the transformation of a tetragonal grain to monoclinic, causes surface uplifts ( Fig. 1 ) and grain pull out. This causes microcracks, which facilitate further the access of the water molecules within the internal grains and therefore the surface initial tetragonal to monoclinic transformation progresses deeper and deeper into the bulk of the material. As the microcracks grow and this process continues, the material fractures. Microstructural factors such as grain size, percentage of stabilizer, residual stresses and manufacturing imperfections may affect this phenomenon [ [10] , [11] , [12] ].

AFM images showing increased roughness and surface uplifts (red arrows on the right image) of transformed 3Y-TZP zirconia grains after aging in autoclave for 10 h.

Although a remarkable number of studies investigating the properties of zirconia ceramics currently exists, due to the fast growing of zirconia technology, new materials are released in the dental market, which have not been adequately evaluated. Consequently, the purpose of this paper was to provide an update to the current knowledge concerning strength and aging resistance of monolithic zirconia ceramics, aiming at highlighting the advantages and weaknesses of conventional and newly-released materials, through the data presented in recent literature.

2. Factors affecting strength and aging resistance of monolithic zirconia

2.1. synthesis of zirconia nanowpowder for dental restorations.

The first step towards the fabrication of monolithic zirconia restorations is the synthesis of the appropriate yttrium stabilized zirconia nanopowder. Nanopowder should be of high purity and with a narrow range of particle sizes, in order to yield densified structures of the desired crystallography. The properties of the starting powders are controled by the method of their production. In order to achieve higher densification, various methods have been developed for synthesizing nanoscale zirconia. These include co-precipitation, hydrothermal treatment, sol-gel, solution combustion synthesis, and mechanochemical processing. In the co-precipitation method, the desired cations are dissolved in an aqueous solution where a chemical precipitant agent is added to cause the precipitation of metal hydroxides. The precipitated powder is filtered, dried and calcined. By modifying the pH and temperature of the solution nucleation and growth mechanisms can be controlled. Although it is a low-cost method, broad particle size distribution and grain agglomeration are unavoidable [ [13] , [14] , [15] ]. Hydrothermal treatment involves an initial co-precipitation, followed by heat treatment at high temperatures to obtain an anhydrous crystalline powder. It is a low cost, soft and ecological method that allows good chemical homogeneity of the product. It can be combined with microwave (microwave-hydrothermal route) to supply further heat for the reactions. Its drawbacks are the long processing time and agglomeration, which leads to low sinterability [ [16] , [17] , [18] ]. The sol-gel method is based on hydrolysis and condensation reactions of inorganic salts and metal-organic compounds that form a sol which is converted into a gel. The gel is then dried and thermally treated to obtain a homogenous nano-powder. It is a low cost method, with relatively simple reaction conditions, that if properly monitored can tailor the microstructure and the chemical composition of the powder. Agglomeration is also a drawback of this method. A modified, nonaqueous sol-gel process has been recently proposed as a novel green method for the preparation of highly dispersive 3 mol% yttria-stabilized zirconia nanopowder with particle sizes of 15–25 nm [ 19 ]. In the solution combustion synthesis , different types of organic fuels (i.e. urea, glycine, sucrose, glucose) or their mixtures are typically dissolved in a solvent (i.e. water, hydrocarbons) with metal nitrate hydrates [ 20 ]. Two modes can be applied for the thermal treatment of the mixture. The first (volume combustion or thermal explosion) involves a sequential thermal treatment in various stages and the second (self-propagating combustion) the locally heating of a small portion of the reactive mixture to initiate an exothermic redox reaction between nitrate ions and the fuel, which self-propagates along with the rest of the volume in the form of a combustion wave. It is a fast method for preparing multicomponent, crystalline, homogeneous, with high purity and narrow particle size oxide nanopowders [ [21] , [22] , [23] ]. For mechanochemical processing, very pure oxide powders are mechanically mixed and milled before calcination. The advantage of mechanochemical synthesis is that it does not require any additional chemicals, such as organic solvents, however milling can result in contamination of the nanopowder, coarser inhomogeneous product and destabilization of the tetragonal zirconia through diffusion of yttrium towards the grain surface [ 24 , 25 ]. The synthesis by chemical routes, is usually more expensive than the mechanical methods, but offers a strict control of the powder characteristics, provided that a very carefull consideration of all the specific synthesis variables is involved.

2.2. CAD/CAM milling

Monolithic and core zirconia frameworks are fabricated through the CAD/CAM technology by milling commercially available blocks, which can be either pre-sintered or fully sintered. Pre-sintered blocks come from a fine grain or nanograin zirconia powder, synthesized as described in section 2.1., which is pressed to high-density compacts through cold isostatic pressing (CIP). Cold isostatic pressing is the most common method for compacting ceramic powders. During cold-isostatic pressing, pressure is applied at ambient temperature, gradually increasing from 50 to 400–1000 MPa and transmitted uniformly on zirconia powder until the green compacts reach 40–60% of their theoretical density prior to sintering [ 26 , 27 ]. Factors enhancing the densification and pore elimination during CIP are nano-sized powder particles, uniform particle size distribution, high specific surface area and low degree of agglomeration. CIP zirconia blocks require a relatively easier and faster milling procedure causing less wear of the machining tools but frameworks present a linear and non-uniform shrinkage of 20–25% during sintering [ 1 , 28 ] leading to non-uniform internal fit of Y-TZP copings [ 28 ]. Fully sintered blocks are prepared by presintering zirconia compacts at temperatures below 1500 °C to reach a density of at least 95% of the theoretical density. Following, hot isostatic pressing (HIP) is performed to increase densification by applying high pressure (50–200 MPa) and high temperature (400–2000 °C) via an inert isostatic gas pressure (e.g., argon or nitrogen). This process aims at eliminating sub-surface voids through a combination of plastic flow and diffusion. For densification of zirconia ceramics the temperature is elevated at temperatures ∼100–200 °C below its sintering temperature and for optimally sintering “green bodies” with no open porosity a remarkable increase in strength can be achieved by HIP [ 29 ] along with a small increase in densification [ 30 ]. Due to their high hardness and low machinability hard machining of HIP processes zirconia ceramics is more time consuming, requires tougher cutting tools and has been correlated to increased roughness, plastic deformation, surface damage, residual stresses’ development [ 31 ] and higher monoclinic phase transformation. The generated cracks, flaws and surface damage cannot be removed during the sintering process, and thus can cause early failure under mechanical loading.

2.3. Sintering

Different sintering methods have been proposed for the densification of CIP zirconia blocks. In general, they include conventional, microwave [ 32 ] and spark plasma sintering [ 33 ].

Conventional sintering of monolithic zirconia includes high temperatures and long heating times, thus being a time and energy consuming process. As it constitutes the most applied method of sintering, various studies have shown that differences in sintering parameters of zirconia can directly affect its microstructure and properties, such as translucency, grain size, and biaxial flexural strength [ 34 , 35 ]. A general trend is that as the sintering temperature increases, translucency and grain size also increase [ [34] , [35] , [36] ], but conflicting evidence exists regarding its effect on flexural strength. For core zirconia ceramics, an increase of sintering temperature above 1550 °C can cause a decrease in flexural strength [ 34 ], probably due to yttrium migration to the grain boundaries [ 37 ]. In the study of Ebeid et al. [ 36 ], who investigated various sintering times for monolithic zirconia, the authors concluded that even at 1600 °C the biaxial flexural strength was not affected. Similar were the results in a recent study by Sen et al. [ 38 ], who investigated various monolithic zirconia ceramics. They reported an increase in translucency by the increase in temperature through grain enlargement and reduction of grain boundaries that act as scattering centers, but no effect on biaxial flexural strength. Although translucency can be improved, larger grain size makes the material more susceptible to transformation [ 39 ] which may jeopardize its mechanical performance.

Microwave sintering is a low cost and time-consuming method. Its main advantage is that heating takes place through molecular interactions with the applied electromagnetic field and effective heating is achieved throughout the material [ 40 ] in significantly less time. In this way, the temperature gradients within the bulk of the material that are usually encountered during conventional sintering are avoided [ 41 ], which is important especially for large and geometrically complicated specimens, such as dental crowns. Almazdi et al. [ 42 ] compared density and flexural strength of specimens prepared from a commercial dental zirconia, and reported that the microwave-sintered specimens had a more uniform grain size distribution and were more closely packed than conventionally sintered specimens. No statistically significant difference was observed in the fracture toughness of various dental zirconia ceramics sintered in microwave or conventional ovens [ 43 , 44 ], suggesting that this method can be widely applied alternatively to conventional sintering. Recently Kim et al. [ 45 ] reported that microwave-sintered pre-colored monolithic zirconia ceramics exhibited similar color appearance and smoother surfaces compared to those conventionally sintered, but with reduced processing time and cost.

Spark plasma sintering, or plasma-activated sintering or field-assisted sintering technique (FAST), is a new promising method for very fast sintering leading to homogeneous and crack-free microstructures [ 46 ] with very limited porosity and high transparency. This technique provides direct contact between heating elements and samples, very rapid heating/cooling rates (several hundreds of °C min −1 ), and uniaxial mechanical pressure. Concerning yttrium stabilized zirconia, limited literature exists [ [47] , [48] , [49] ] but the results show that the material can reach very rapid densification with no cracks, shape distortions or density gradients in sintered samples with complex shapes and dimensions of centimeters [ 49 ]. However in-vitro studies are needed to evaluate the feasibility and effectiveness of this sintering method for monolithic zirconia ceramics.

2.4. Coloring of monolithic zirconia

For monolithic zirconia restorations, coloring can be achieved either by using pre-colored blocks or by immersing white zirconia restorations in coloring liquid or brushing their surfaces with it. Coloring liquids are solutions of metal oxides such as ferric chloride, manganese chloride, cerium acetate, cerium chloride, bismuth chloride, terbium (III) chloride, chromium (III) chloride, manganese (II) sulfate, etc. The effects of liquid-coloring on the properties of zirconia have been investigated in a few studies. In regards to LTD, liquid coloring has not been correlated with phase transformation but on the other hand, higher resistance to LTD compared to uncolored control specimens has been reported [ 50 , 51 ]. However, the mechanical properties of the liquid colored zirconia ceramics seem to be affected by the process. Although a few studies report no effect on flexural strength [ [52] , [53] , [54] ], there are a lot of studies emphasizing that immersion in coloring liquid can have detrimental effects on its flexural and fracture strength, hardness and densification [ 51 , 55 ]. Ban et al. [ 56 ] reported that in cases of liquids containing erbium (Er), and neodymium (Nd), both crystalline changes (presence of cubic phases) and decrease in mechanical properties can occur, attributed to the stabilization of the ions in the crystal lattice. Although significant t→m transformation is not recorded after aging, the increased grain size and open porosity attributed to some coloring oxides after sintering may negatively affect both the optical and mechanical properties [ 51 ].

Pre-coloring involves the synthesis of colored nanopowder by incorporating metal oxides such as Fe 2 O 3 [ 57 , 58 ], Bi 2 O 3 [ 57 ], CeO 2 [ 59 ], Er 2 O 3 [ 59 , 60 ], MnO 2 [ 61 , 62 ] and Pr 6 O 11 [ 60 ]. Doping oxides in pre-colored zirconia may have a negative effect on its mechanical properties [ 60 ]. This comes as a result of the changes in the crystal lattice that take place due to the replacement of a Zr ion with a metal ion. Depending on the valence and the ionic radius of the metal ion that enters zirconia crystal lattice, formation of oxygen vacancies and changes in lattice dimension (expansion or contraction) can occur [ 63 ], variously affecting both the mechanical/physical properties and color characteristics of zirconia [ 64 , 65 ]. By adding various amounts of Fe 2 O 3 -which is the most common oxide for zirconia coloring- into a 3 mol% Y 2 O 3 zirconia powder, Kao et al. [ 66 ] produced powders with varying combinations of red and yellow. Although the densification and sintering of the powders were improved, the size of zirconia grains as well as the monoclinic content was increased along with Fe content, making it necessary to reduce the total amount of the applied oxide [ 66 ].

3. Strength of monolithic zirconia

Although dental zirconia is the strongest dental material in terms of flexural strength and fracture resistance, during the last few years, the translucency of zirconia ceramics has increased at the expense of strength, and translucent full-contour, monolithic zirconia restorations have become increasingly popular as a result of advances in CAD/CAM technology. There are 2 types of monolithic zirconia materials; opaque and translucent zirconia. Opaque zirconia offers significantly greater flexural strength and is indicated for the posterior regions of the mouth, while translucent zirconia has the more natural esthetic appearance but lower mechanical properties. The presence of cubic zirconia in translucent compositions is responsible for the enhanced optical properties; however, a significant reduction of the mechanical properties is a consequent drawback. The mechanical strength of monolithic zirconia was evaluated in many studies, depicted in the following tables ( Table 1 , Table 2 ).

Studies investigating the strength of monolithic zirconia crowns. Studies are presented in ascending chronological order.

The composition of the materials presented in this and all the tables in the manuscript are presented in Table 5 .

Studies investigating mechanical properties of monolithic zirconia specimens. Studies are presented in ascending chronological order.

Concerning fracture resistance of monolithic zirconia crowns, a clear superiority exists for full-contour monolithic crowns, even if they are glass-infiltrated [ 68 ], compared to veneered bilayer [ 67 , 77 , 78 ] and lithium disilicate crowns [ [69] , [70] , [71] , 79 ]. Reis et al. [ 80 ], used the sol-gel method to infiltrate zirconia surfaces with silica in order to eliminate veneering ceramic delamination. This procedure only enhanced the structural homogeneity and hardness of monolithic zirconia, but it reduced its fracture toughness.

After cyclic loading, high translucency tetragonal zirconia demonstrated the higher fatigue strength among a feldspathic ceramic, a polymer-infiltrated ceramic network, a lithium disilicate glass-ceramic and a zirconia-reinforced lithium silicate glass-ceramic [ 81 ]. According to Pereira et al. [ 82 ], third generation ultra-translucent monolithic zirconia materials present no transformation toughening when aged as well as significantly inferior mechanical properties. All fractures started from surface defects on the tensile surface. High-translucency monolithic zirconia has a reduced bi-axial flexural strength compared to conventional zirconia, but it is appropriate for clinical us [ 83 ]. According to Camposilva et al. [ 84 ], translucent zirconia presents significantly lower toughness and strength compared to conventional zirconia ceramics and it should be considered carefully for clinical application.

The occlusal thickness of the crown has shown to be correlated to fracture [ 69 , 70 ], as well as the presence of an occlusal groove [ 75 ]. Monolithic zirconia crowns cemented on abutments with an occlusal groove presented lower fracture resistance compared to crowns cemented on abutments with flat occlusal surfaces [ 75 ]. Sun et al. [ 69 ], reported a threefold increase from 0.6 to 1.5 mm, but on the contrary, Sorrentino et al. [ 72 ] did not find any significant correlation. It has recently been reported by Weigl et al. [ 85 ], that monolithic zirconia crowns with a thickness of 0.5 mm ensure acceptable strength regardless of the type of cementation, following in-vitro cyclic loading to simulate the clinical function of the restoration. However, thickness of 0.2 mm was too low to establish predictability, regardless of cement type. Ozer et al. [ 86 ] suggest that thickness between 0.7 and 1.3 mm are ideal for the fabrication of monolithic zirconia restorations and air-borne particle abrasion enhances the materials flexural strength, whereas grinding and polishing did not influence the material’s strength. Schriwer et al. [ 73 ] investigated the strength of hard machined versus soft machined premolar crowns and resulted that the hard-machined Y-TZP crowns had the best margin quality and the highest load at fracture, pointing out the significance of good marginal fit for higher performance. Sarikaya et al. [ 87 ] reported that Bruxzir and Incoris TZI monolithic zirconia systems present acceptable resistance to fracture for the fabrication of monolithic crowns when tested at physiologic mastication forces. Overall, several studies have concluded that high translucency cubic zirconia presents significantly lower mechanical properties due to the absence of transformation toughening mechanism and this can compromise their use in clinical cases where high loads are applied [ 84 , 88 ]. An increase of yttrium oxide percentage in zirconia ceramics can lead to a reduction of the mechanical strength, but only following artificial aging [ 88 ]. However, even the high-translucency materials demonstrate fracture strength acceptable for clinical application exceeding 3000 N [ 88 ]. According to Yin et al. [ 89 ], the fracture strength of monolithic zirconia crowns increased after treatment with polishing burs and polishing can reduce the monoclinic phase.

Several studies have evaluated the fracture resistance of monolithic zirconia crowns retained by implants. According to Moilanen et al. [ 76 ], the fabrication technique of monolithic zirconia implant-retained crowns using a prefabricated titanium base led to crowns with superior strength to static mechanical testing compared to crowns fabricated directly on the implant surface. According to Rohr et al. [ 74 ], the use of resin cements with high compressive strength was found to be correlated linearly to fracture resistance and flexural strength of implant-supported monolithic zirconia crowns. Elshiyab et al. [ 90 ] proved that after 5 years equivalent chewing simulation, implant retained monolithic zirconia crowns survived, although their resistance to fracture had decreased.

The effect of grinding and polishing on monolithic zirconia restorations has been evaluated by a few studies. In the study of Khayat et al. [ 91 ], grinding was found to increase the surface roughness of monolithic zirconia and decrease the flexural strength. However, polishing after grinding leads to the preservation of the flexural strength. The authors suggest that monolithic zirconia’s mechanical strength can be compromised when zirconia surfaces are left rough leading to higher susceptibility to aging. The monolithic zirconia ceramic evaluated was not compromised by grinding and low-temperature degradation and both thicknesses tested maintained acceptable mechanical strength [ 92 ]. Polishing after grinding was determined mandatory in order to prevent crack propagation and to enhance the material’s fatigue [ 93 ]. A 2nd generation zirconia ceramic was submitted to grinding and artificial aging to assess its fatigue strength and survival rates and it was found that its properties were not compromised [ 94 ].

In order to evaluate sintering parameters for monolithic zirconia, specimens were submitted to air-borne particle abrasion and silica coating in the pre-sintered stage and this led to higher biaxial flexural strength. Thus, surface pre-treatment in the pre-sintered stage of monolithic zirconia might be beneficial to the final restoration’s strength [ 95 ]. Juntavee et al. [ 96 ] studied the effect of sintering temperature and duration alterations and proved that high sintering temperature combined with long sintering time attribute higher flexural strength and hence translucent monolithic zirconia restorations with higher strength.

Based on the majority of the studies included in Table 2 , it can be concluded that high translucent specimens of zirconia ceramics with yttrium content >3 mol% present significantly lower strength compared to the partial stabilized 3 mol% Y-TZP ones ( Fig. 2 ) [ [97] , [98] , [99] , [100] , [101] , [102] , [103] ]. However, translucent zirconia ceramics with 3 mol% Y-TZP presented similar strength compared to conventional 3 mol% Y-TZP ceramics [ 64 , 104 ]. In addition, Candido et al. [ 105 ] reported that the monolithic zirconia tested showed similar flexural strength to a conventional zirconia ceramic. All monolithic zirconia specimens presented higher strength compared to lithium disilicate ones [ 64 , 106 ], although this is not in agreement with a recent study by Yan et al. [ 107 ] who reported that when bonded on a dentin-like substrate, lithium disilicate presented higher load-bearing capacity compared to an ultra-translucent 5Y-PSZ ceramic. Compared to veneered specimens one study reported higher strength for bilayer [ 106 ] and another similar strength for trilayer specimens [ 108 ]. Sakai et al. [ 109 ] reported that layering zirconia of various translucencies with resin cement between the layers is a method that improves the optical properties of the restoration while maintaining the flexural strength of the monolithic zirconia ceramic. Sulaiman et al. [ 100 , 101 ] investigated the effect of staining on partially and fully stabilized zirconia specimens and reported a significant increase of strength for fully stabilized monolithic zirconia ceramics. Air-borne particle abrasion had a positive effect on the strength of partially stabilized but a detrimental effect to fully stabilized zirconia specimens [ 100 , 110 ], while glazing had either no effect [ 111 ] or positive effect [ 112 ] on partially stabilized zirconia specimens. According to Nam et al. [ 113 ], glazing of translucent monolithic zirconia plates led to a significant reduction in flexural strength, whereas low-temperature degradation did not present any significant effects.

Graphical summary with the major findings of this review regarding strength and aging resistance of high translucency zirconia ceramics.

3.1. Aging resistance

Aging resistance of monolithic zirconia restorations is a fundamental property as the whole surface is exposed to aggressive oral conditions. The aging behavior of zirconia is generally investigated through an accelerating aging test in an autoclave [ 116 ]. According to theoretical calculations, 1 h at 134 °C corresponds to 3–4 years in-vivo . By this, 10 h of in-vitro aging, have theoretically the same effect as a restoration in the oral cavity for 30–40 years, which is a more than sufficient lifespan for a fixed partial denture (FPD). Despite the criticism that this test does not correspond to actual clinical conditions and that it may underestimate the actual degradation of zirconia ceramics in the oral environment [ 117 ], it still remains an efficient method to estimate the long-term performance of these materials. Other tests include boiling in hot water or artificial saliva, mechanical cyclic loading, thermocycling, and combinations of mechanical and thermal fatigue.

Autoclave aging has been correlated to no significant change in strength [ 84 , 118 , 119 ], as well as to significant decrease and increase depending on time of treatment, brand and composition [ 120 , 121 ] of the zirconia system investigated ( Table 3 , Table 4 ). Comparing 3 mol% Y-TZP ceramics with translucent monolithic ceramics of higher yttrium amount [ 101 , 121 , 122 ], significantly higher resistance to aging degradation was recorded for the new generation translucent ceramics, but only after prolonged aging [ 84 , 121 ]. This is not in agreement with Almansour et al. [ 83 ], whose study found significant differences in several monolithic zirconia systems following shorter periods of aging. In a recent study [ 121 ], the monoclinic phase fraction increased remarkably between 5 and 50 h of aging, especially for Prettau and BruxZir, and less for Katana ML and Katana HT13. The aged specimens had a detectable layer of transformed material which reached ˜60 μm in Prettau and BruxZir and less than 5 μm in Katana ML and HT13. Although significant differences were recorded, these exceedingly long periods of accelerating autoclave treatment (usually after 10 h) are beyond the clinical lifespan of a restoration. In the other three studies [ 99 , 101 , 122 ] investigating the ultra-translucent Pretau Anterior zirconia, no significant differences in strength were recorded after 8 h of steam autoclave treatment in two of the studies [ 101 , 122 ] and significant reduction in one studies [ 99 ]. Similarly, no significant change in strength was recorded in another study [ 84 ], neither for 3 mol% nor for 5.5 and >6 mol% translucent zirconia ceramics, even after the significant amount of m-ZrO 2 present on their surface ( Table 5 ).

Studies investigating mechanical properties of monolithic zirconia specimens/crowns after hydrothermal aging (steam autoclave and boiled water/artificial saliva). Studies are presented in ascending chronological order.

Studies investigating mechanical properties of monolithic zirconia specimens/crowns after cycling loading, mechanical loading and various combinations of thermomechanical loading. Studies are presented in chronological order.

Commercial products listed in the studies included in the review, manufacturers and compositions.

Guilardi et al. [ 123 ] examined the effects of grinding and low temperature aging on flexural strength, roughness, and phase transformation of Y-TZP ceramics. Grinding increased significantly the characteristic strength and affected positively the material’s sensitivity to the tetragonal to monoclinic phase transformation during aging, a transformation which was less for the fine ground specimens. Exactly the same results came from the study of Pereira et al. [ 124 ]. On the other side, Khayat et al. [ 91 ] reported that grinding alone can significantly increase roughness and make the material more prone to aging, however they did not investigate the effect of aging on the strength of rough grinded specimens. Polishing after grinding, however, significantly reduced roughness. Although boiling in artificial saliva for 7 days increased monoclinic fraction from 2.4% to 21%, the increase was superficial and there was no reduction in strength, but in some ceramics, an increase was recorded instead [ 118 ]. The flexural strength was not affected by the amount of monoclinic fraction on the surface. Dehestani and Adolfsson [ 125 ] found no significant change in strength after immersion in boiling water up to 6 months, although a significant amount of monoclinic fraction was recorded after 32 days (50% for 3 Y-TZP monolithic ceramics). On the recent study of Pereira et al. [ 82 ], three different translucencies of monolithic zirconia ceramics were evaluated following autoclave aging at 134 °C under pressure of 2 bars pressure for 20 h and it was reported that the high translucency system presented a significant increase in flexural strength as well as increased monoclinic phase percentage, compared to the super- and ultra-translucency systems. Another recent study’s findings, in which monolithic zirconia specimens were submitted to fatigue strength test, have shown that ground specimens presented higher fatigue strength, whereas ground specimens which were submitted to autoclave aging presented lower percentages of monoclinic phase [ 94 ]. This is in agreement with previous findings from Prado et al. [ 92 ].

Concerning the effect of steam autoclave aging on molar crowns’ strength, significant reduction of strength up to 50 h of autoclave treatment has been reported [ 126 ] and no further reduction afterwards, while Leone et al. [ 127 ] reported significant reduction after 54 h of autoclave treatment only for the 3 mol% Y-TZP, and no change for the ultra high translucent zirconia, which however presented the lowest mechanical properties. On the other hand, in other studies [ 120 , 128 ], no significant difference among various brands of 3–5 mol% Y-TZP monolithic zirconia crowns was found, even after 50 h of aging [ 120 , 126 ]. Although limited evidence exists concerning ultra high translucent ceramics, they seem to present a high resistance to degradation, but lower mechanical strength [ 127 ].

Chewing simulator did not induce any significant alterations in the strength values of 3 mol% Y-TZ specimens, but all monolithic zirconia materials presented lower values compared to the conventional one [ 119 ]. In a recent study by Elsayed et al. [ 88 ], which evaluated the fracture strength of 3Y-TZP, 4Y-TZP and 5Y-TZP molar crowns following chewing simulation with simultaneous thermocycling, supports that crowns from zirconia with high Y 2 O 3 content presented higher fracture strength. On the contrary, significantly higher decrease in strength after mechanical cyclic loading was recorded for 8 mol% monolithic zirconia specimens, especially after the combination of thermal and mechanical cycling [ 99 ]. In another study, unglazed monolithic crowns presented the lowest strength after thermal cycling in water [ 129 ]. In the opposite direction, other studies report that thermal cycling alone does not decrease significantly the fracture load of monolithic zirconia crowns as does the combination of mechanical and thermal aging, which according to Bergamo et al. [ 28 ], also increases the amount of monoclinic phase more than eightfold on the mesial palatal cusp of the crowns (8.3–8.9%). It was further reported that circumferential shoulderless preparation had a significantly higher fracture load than other groups [ 130 ]. No difference in strength between crowns made of high-translucent (HTZ) or low-translucent (LTZ) zirconia has been reported [ 131 ] while yttria stabilized zirconia presented higher resistance to fracture compared to lithium disilicate crowns [ 90 , 132 ]. According to Sarıkaya et al. [ 87 ], Bruxzir monolithic zirconia crowns and FPDs present higher fracture strength compared to Incoris TZI following simultaneous chewing simulation (1,200,000 cycles) and thermocycling (10,000 cycles). With regards to material thickness, according to Weigl et al. [ 85 ], monolithic zirconia crowns as thin as 0.2 mm present acceptable fracture strength test when they are cemented with adhesive luting agents. The fracture strength of 3 mol% Y-TZP monolithic 3-unit FDPs has been found similar to that of veneered bilayer FDPs [ 97 , 99 ], while glass infiltration of a sol-gel glass has been found to increase the fatigue limits of the restorations [ 100 ]. As expected, increased occluso-cervical thickness and decreased length of cantilevered frameworks were advantageous for higher loads. Sarıkaya et al. [ 87 ] reported that monolithic zirconia 3-unit FDPs fabricated with two different ceramic systems demonstrate acceptable fracture strength even after 5 years equivalent of chewing simulation.

4. Conclusions

Latest developments in CAD-CAM technology have rendered monolithic zirconia restorations a well-established restorative treatment in prosthodontic cases with advanced mechanical and esthetic needs. Various production synthesis and sintering parameters have been utilized, leading to promising results, however, further research is still needed for solid conclusions. Concerning tooth color reproduction, there are a lot of issues to be resolved, as multiple factors can affect the final color of a monolithic zirconia restoration. In regards to strength, ultra translucent fully stabilized monolithic zirconia ceramics present significantly lower strength compared to tetragonal partially stabilized ones, and thus should probably be applied only in areas with minimal biting forces, such as the anterior regions of the mouth or in patients without parufunctional habits and bruxism. The absence of aging sensitivity, however, may overwhelm their low strength, but only well designed clinical studies can verify or reject this hypothesis. However, it would be safe to suggest the utilization of the high-strength partially stabilized zirconia for posterior or long span restorations and fully stabilized ultra-translucent zirconia for anterior short span fixed partial dentures.

To summarize, despite the obvious advantages of contemporary monolithic zirconia ceramics, new scientific data emerges constantly about their properties, the limitations in their application and their resistance to low-temperature degradation that will eventually reach to laboratory and clinical guidelines for their use. However, monolithic zirconia ceramics include a group of materials with different properties and sound scientific knowledge should guide the selection of the appropriate material in each clinical situation.

Conflicts of interest

1. Denry I., Kelly J.R. State of the art of zirconia for dental applications. Dent Mater. 2008;24:299–307. doi: 10.1016/j.dental.2007.05.007. [ DOI ] [ PubMed ] [ Google Scholar ]
2. Denry I., Kelly J.R. Emerging ceramic-based materials for dentistry. J Dent Res. 2014;93:1235–1242. doi: 10.1177/0022034514553627. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
3. Piconi C., Maccauro G. Zirconia as a ceramic biomaterial. Biomaterials. 1999;20:1–25. doi: 10.1016/s0142-9612(98)00010-6. [ DOI ] [ PubMed ] [ Google Scholar ]
4. Garvie R.C., Hannink R.H., Pascoe R.T. Ceramic steel? Nature. 1975;258:703–704. [ Google Scholar ]
5. Vagkopoulou T., Koutayas S.O., Koidis P., Strub J.R. Zirconia in dentistry: part 1. Discovering the nature of an upcoming bioceramic. Eur J Esthet Dent. 2009;4:130–151. [ PubMed ] [ Google Scholar ]
6. Koutayas S.O., Vagkopoulou T., Pelekanos S., Koidis P., Strub J.R. Zirconia in dentistry: part 2. Evidence-based clinical breakthrough. Eur J Esthet Dent. 2009;4:348–380. [ PubMed ] [ Google Scholar ]
7. Gupta T.K., Lange F.F., Bechtold J.H. Effect of stress-induced phase transformation on the properties of polycrystalline zirconia containing metastable tetragonal phase. J Mater Sci. 1978;13:1464–1470. [ Google Scholar ]
8. Chevalier J., Gremillard L., Deville S. Low-temperature degradation of zirconia and implications for biomedical implants. Annu Rev Mater Res. 2007;37:1–32. [ Google Scholar ]
9. Chevalier J., Cales B., Drouin J.M. Low-temperature aging of Y-TZP ceramics. J Am Ceram Soc. 2004;82:2150–2154. [ Google Scholar ]
10. Lawson S. Environmental degradation of zirconia ceramics. J Eur Ceram Soc. 1995;15:485–502. [ Google Scholar ]
11. Deville S., Chevalier J., Gremillard L. Influence of surface finish and residual stresses on the ageing sensitivity of biomedical grade zirconia. Biomaterials. 2006;27:2186–2192. doi: 10.1016/j.biomaterials.2005.11.021. [ DOI ] [ PubMed ] [ Google Scholar ]
12. Chevalier J., Gremillard L., Virkar A.V., Clarke D.R. The tetragonal-monoclinic transformation in zirconia: lessons learned and future trends. J Am Ceram Soc. 2009;92:1901–1920. [ Google Scholar ]
13. Hsu Y.W., Yang K.H., Chang K.M., Yeh S.W., Wang M.C. Synthesis and crystallization behavior of 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) nanosized powders prepared using a simple co-precipitation process. J Alloys Compd. 2011;509:6864–6870. [ Google Scholar ]
14. Maridurai T., Balaji D., Sagadevan S. Synthesis and characterization of yttrium stabilized zirconia nanoparticles. Mater Res. 2016;19:812–816. [ Google Scholar ]
15. Geethalakshmi K., Prabhakaran T., Hemalatha J. Dielectric studies on nano zirconium dioxide synthesized through co-precipitation process. World Acad Sci Eng Technol. 2012;64:179–182. [ Google Scholar ]
16. Gonzalo-Juan I., Ferrari B., Colomer M.T. Influence of the urea content on the YSZ hydrothermal synthesis under dilute conditions and its role as dispersant agent in the post-reaction medium. J Eur Ceram Soc. 2009;29:3185–3195. [ Google Scholar ]
17. Lach R., Bu M.M., Haberko K., Marian R. Translucent zirconia polycrystals prepared from nanometric powders. Procesing Apl Dent Ceram. 2015:175–180. [ Google Scholar ]
18. Sato K., Horiguchi K., Nishikawa T., Yagishita S., Kuruma K., Murakami T. Hydrothermal synthesis of yttria-stabilized zirconia nanocrystals with controlled yttria content. Inorg Chem. 2015;54:7976–7984. doi: 10.1021/acs.inorgchem.5b01112. [ DOI ] [ PubMed ] [ Google Scholar ]
19. Feng G., Jiang W., Liu J., Zhang Q., Wu Q., Miao L. A novel green nonaqueous sol-gel process for preparation of partially stabilized zirconia nanopowder. Process Appl Ceram. 2017;11:220–224. [ Google Scholar ]
20. Varma A., Mukasyan, Rogachev A., Manukyan K. Solution combustion synthesis of nanoscale materials. Chem Rev. 2016;116:14493–14586. doi: 10.1021/acs.chemrev.6b00279. [ DOI ] [ PubMed ] [ Google Scholar ]
21. Silva D., A. C, Ribeiro N.F.P., Souza M.M.V.M. Effect of the fuel type on the synthesis of yttria stabilized zirconia by combustion method. Ceram Int. 2009;35:3441–3446. [ Google Scholar ]
22. Limaye A., Helble J. Morphological control of zirconia nanoparticles through combustion aerosol synthesis. J Am Ceram Soc. 2002;32:1127–1132. [ Google Scholar ]
23. Han A., Wu Z., Zou H. One-step alkali chloride-assisted solution combustion synthesis of 3YSZ nanopowders with ultrahigh specific surface area. Ceram Int. 2017;43:16043–16047. [ Google Scholar ]
24. Dodd A.C., Tsuzuki T., McCormick P.G. Nanocrystalline zirconia powders synthesised by mechanochemical processing. Mater Sci Eng A. 2001;301:54–58. [ Google Scholar ]
25. Macan J., Brcković L., Gajović A. Influence of preparation method and alumina content on crystallization and morphology of porous yttria stabilized zirconia. J Eur Ceram Soc. 2017;37:3137–3149. [ Google Scholar ]
26. Amat N.F., Muchtar A., Amril M.S., Ghazali M.J., Yahaya N. Preparation of presintered zirconia blocks for dental restorations through colloidal dispersion and cold isostatic pressing. Ceram Int. 2018;44:6409–6416. [ Google Scholar ]
27. Akimov G.Y. Cold isostatic pressing as a method for fabricating ceramic products with high physicomechanical properties. Refract Ind Ceram. 1998;39:283–287. [ Google Scholar ]
28. Edwards Rezende C.E., Sanches Borges A.F., Macedo R.M., Rubo J.H., Griggs J.A. Dimensional changes from the sintering process and fit of Y-TZP copings: micro-CT analysis. Dent Mater. 2017;33:e405–e413. doi: 10.1016/j.dental.2017.08.191. [ DOI ] [ PubMed ] [ Google Scholar ]
29. Druschitz A.P., Schroth J.G. Hot isostatic pressing of a presintered yttria-stabilized zirconia ceramic. J Am Ceram Soc. 1989;72:1591–1597. [ Google Scholar ]
30. Scherrer S.S., Cattani-Lorente M., Yoon S., Karvonen L., Pokrant S., Rothbrust F. Post-hot isostatic pressing: a healing treatment for process related defects and laboratory grinding damage of dental zirconia? Dent Mater. 2013;29:e180–190. doi: 10.1016/j.dental.2013.04.014. [ DOI ] [ PubMed ] [ Google Scholar ]
31. Denkena B., Breidenstein B., Busemann S., Lehr C.M. Impact of hard machining on zirconia based ceramics for dental applications. Procedia Cirp. 2017;65:248–252. [ Google Scholar ]
32. Borrell A., Salvador M.D., Peñaranda-Foix F.L., Cátala-Civera J.M. Microwave sintering of Zirconia materials: mechanical and microstructural properties. Int J Appl Ceram Technol. 2013;10:313–320. [ Google Scholar ]
33. Ahsanzadeh-Vadeqani M., Razavi R.S. Spark plasma sintering of zirconia-doped yttria ceramic and evaluation of the microstructure and optical properties. Ceram Int. 2016;42:18931–18936. [ Google Scholar ]
34. Stawarczyk B., Özcan M., Hallmann L., Ender A., Mehl A., Hämmerlet C.H.F. The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio. Clin Oral Invest. 2013;17:269–274. doi: 10.1007/s00784-012-0692-6. [ DOI ] [ PubMed ] [ Google Scholar ]
35. Kim M.-J., Ahn J.-S., Kim J.-H., Kim H.-Y., Kim W.-C. Effects of the sintering conditions of dental zirconia ceramics on the grain size and translucency. J Adv Prosthodont. 2013;5:161–166. doi: 10.4047/jap.2013.5.2.161. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
36. Ebeid K., Wille S., Hamdy A., Salah T., El-Etreby A., Kern M. Effect of changes in sintering parameters on monolithic translucent zirconia. Dent Mater. 2014;30 doi: 10.1016/j.dental.2014.09.003. e419–24. [ DOI ] [ PubMed ] [ Google Scholar ]
37. Jiang L., Liao Y., Wan Q., Li W. Effects of sintering temperature and particle size on the translucency of zirconium dioxide dental ceramic. J Mater Sci Mater Med. 2011;22:2429–2435. doi: 10.1007/s10856-011-4438-9. [ DOI ] [ PubMed ] [ Google Scholar ]
38. Sen N., Sermet I.B., Cinar S. Effect of coloring and sintering on the translucency and biaxial strength of monolithic zirconia. J Prosthet Dent. 2017;19(2) doi: 10.1016/j.prosdent.2017.08.013. 308.e1-308.e7. [ DOI ] [ PubMed ] [ Google Scholar ]
39. Lucas T.J., Lawson N.C., Janowski G.M., Burgess J.O. Effect of grain size on the monoclinic transformation, hardness, roughness, and modulus of aged partially stabilized zirconia. Dent Mater. 2015;31:1487–1492. doi: 10.1016/j.dental.2015.09.014. [ DOI ] [ PubMed ] [ Google Scholar ]
40. Menezes R.R., Souto P.M., Kiminami R.H.G.A. Microwave sintering of ceramic materials. IOP Conf Ser Mater Sci Eng. 2016;161 [ Google Scholar ]
41. Karayannis V.G. Microwave sintering of ceramic materials. IOP Conf Ser Mater Sci Eng. 2016;161 [ Google Scholar ]
42. Almazdi A.A., Khajah H.M., Monaco E.A., Kim H. Applying microwave technology to sintering dental zirconia. J Prosthet Dent. 2012;108:304–309. doi: 10.1016/S0022-3913(12)60181-4. [ DOI ] [ PubMed ] [ Google Scholar ]
43. Marinis A., Aquilino S.A., Lund P.S., Gratton D.G., Stanford C.M., Diaz-Arnold A.M. Fracture toughness of yttria-stabilized zirconia sintered in conventional and microwave ovens. J Prosthet Dent. 2013;109:165–171. doi: 10.1016/S0022-3913(13)60037-2. [ DOI ] [ PubMed ] [ Google Scholar ]
44. Upadhyaya D.D., Ghosh A., Dey G.K., Prasad R., Suri A.K. Microwave sintering of zirconia ceramics. J Mater Sci. 2001;36:4707–4710. [ Google Scholar ]
45. Kim H.-K., Kim S.-H. Comparison of the optical properties of pre-colored dental monolithic zirconia ceramics sintered in a conventional furnace versus a microwave oven. J Adv Prosthodont. 2017;9:394–401. doi: 10.4047/jap.2017.9.5.394. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
46. Anselmi-Tamburini U., Woolman J.N., Munir Z.A. Transparent nanometric cubic and tetragonal zirconia obtained by high-pressure pulsed electric current sintering. Adv Funct Mater. 2007;17:3267–3273. [ Google Scholar ]
47. Vasylkiv O., Borodianska H., Sakka Y., Demirskyi D. Flash spark plasma sintering of ultrafine yttria-stabilized zirconia ceramics. Scr Mater. 2016;121:32–36. [ Google Scholar ]
48. Lei L., Fu Z., Wang H., Lee S.W., Niihara K. Transparent yttria stabilized zirconia from glycine-nitrate process by spark plasma sintering. Ceram Int. 2012;38:23–28. [ Google Scholar ]
49. Salamon D., MacA K., Shen Z. Rapid sintering of crack-free zirconia ceramics by pressure-less spark plasma sintering. Scr Mater. 2012;66:899–902. [ Google Scholar ]
50. Kaplan M., Park J., Young Kim S., Ozturk A. Production and properties of tooth-colored yttria stabilized zirconia ceramics for dental applications. Ceram Int. 2018;44:2413–2418. [ Google Scholar ]
51. Shah K., Holloway J.A., Denry I.L. Effect of coloring with various metal oxides on the microstructure, color, and flexural strength of 3Y-TZP. J Biomed Mater Res - Part B Appl Biomater. 2008;87:329–337. doi: 10.1002/jbm.b.31107. [ DOI ] [ PubMed ] [ Google Scholar ]
52. Sedda M., Vichi A., Carrabba M., Capperucci A., Louca C., Ferrari M. Influence of coloring procedure on flexural resistance of zirconia blocks. J Prosthet Dent. 2015;114:98–102. doi: 10.1016/j.prosdent.2015.02.001. [ DOI ] [ PubMed ] [ Google Scholar ]
53. Oh G.J., Lee K., Lee D.J., Lim H.P., Yun K.D., Ban J.S. Effect of metal chloride solutions on coloration and biaxial flexural strength of yttria-stabilized zirconia. Met Mater Int. 2012;18:805–812. [ Google Scholar ]
54. Pittayachawan P., McDonald A., Petrie A., Knowles J.C. The biaxial flexural strength and fatigue property of LavaTM Y-TZP dental ceramic. Dent Mater. 2007;23:1018–1029. doi: 10.1016/j.dental.2006.09.003. [ DOI ] [ PubMed ] [ Google Scholar ]
55. Hjerppe J., Närhi T., Fröberg K., Vallittu P.K., Lassila L.V.J. Effect of shading the zirconia framework on biaxial strength and surface microhardness. Acta Odontol Scand. 2008;66:262–267. doi: 10.1080/00016350802247123. [ DOI ] [ PubMed ] [ Google Scholar ]
56. Ban S., Suzuki T., Yoshihara K., Sasaki K., Kawai T., Kono H. Effect of coloring on mechanical properties of dental zirconia. J Med Biol Eng. 2014;34:24–29. [ Google Scholar ]
57. Wen N., Yi Y., Zhang W., Deng B., Shao L., Dong L. The color of Fe2O3 and Bi2O3 pigmented dental zirconia ceramic. Key Eng Mater. 2010;435:582–585. [ Google Scholar ]
58. Kaya G. Production and characterization of self-colored dental zirconia blocks. Ceram Int. 2013;39:511–517. [ Google Scholar ]
59. Huang H., Zhang F.Q., Sun J., Gao L. Effect of three kinds of rare earth oxides on chromaticity and mechanical properties of zirconia ceramic. Zhonghua Kou Qiang Yi Xue Za Zhi. 2006;41:327–330. [ PubMed ] [ Google Scholar ]
60. Li J., Liu S.M., Lin Y.H. Synthesis of coloured dental zirconia ceramics and their mechanical behaviors. Key Eng Mater. 2014;602–603:594–597. [ Google Scholar ]
61. Liu S.M., Liu J., Deng X.L., Lin Y.H., Liu F. Color reproduction and shade stability of zirconia ceramics. Key Eng Mater. 2014;602–603:610–614. [ Google Scholar ]
62. Huang H., Zheng Y.L., Zhang F.Q., Sun J., Gao L. [Effect of five kinds of pigments on the chromaticity of dental zirconia ceramic] Shanghai Kou Qiang Yi Xue. 2007;16:413–417. [ PubMed ] [ Google Scholar ]
63. Rada S., Culea E., Rada M. Novel ZrO2based ceramics stabilized by Fe2O3, SiO2 and Y2O3. Chem Phys Lett. 2018;696:92–99. [ Google Scholar ]
64. Church T.D., Jessup J.P., Guillory V.L., Vandewalle K.S. Translucency and strength of high-translucency monolithic zirconium oxide materials. Gen Dent. 2017;65:48–52. [ PubMed ] [ Google Scholar ]
65. Casolco S.R., Xu J., Garay J.E. Transparent/translucent polycrystalline nanostructured yttria stabilized zirconia with varying colors. Scr Mater. 2008;58:516–519. [ Google Scholar ]
66. Kao C.T., Tuan W.H., Liu C.Y., Chen S.C. Effect of iron oxide coloring agent on the sintering behavior of dental yttria-stabilized zirconia. Ceram Int. 2017;44:4689–4693. [ Google Scholar ]
67. Beuer F., Stimmelmayr M., Gueth J.F., Edelhoff D., Naumann M. In vitro performance of full-contour zirconia single crowns. Dent Mater. 2012;28:449–456. doi: 10.1016/j.dental.2011.11.024. [ DOI ] [ PubMed ] [ Google Scholar ]
68. Zhang Y., Chai H., Lee J.J.W., Lawn B.R. Chipping resistance of graded zirconia ceramics for dental crowns. J Dent Res. 2012;91:311–315. doi: 10.1177/0022034511434356. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
69. Sun T., Zhou S., Lai R., Liu R., Ma S., Zhou Z. Load-bearing capacity and the recommended thickness of dental monolithic zirconia single crowns. J Mech Behav Biomed Mater. 2014;35:93–101. doi: 10.1016/j.jmbbm.2014.03.014. [ DOI ] [ PubMed ] [ Google Scholar ]
70. Nakamura K., Harada A., Inagaki R., Kanno T., Niwano Y., Milleding P. Fracture resistance of monolithic zirconia molar crowns with reduced thickness. Acta Odontol Scand. 2015;73:602–608. doi: 10.3109/00016357.2015.1007479. [ DOI ] [ PubMed ] [ Google Scholar ]
71. Zhang Y., Mai Z., Barani A., Bush M., Lawn B. Fracture-resistant monolithic dental crowns. Dent Mater. 2016;32:442–449. doi: 10.1016/j.dental.2015.12.010. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
72. Sorrentino R., Triulzio C., Tricarico M.G., Bonadeo G., Gherlone E.F., Ferrari M. In vitro analysis of the fracture resistance of CAD-CAM monolithic zirconia molar crowns with different occlusal thickness. J Mech Behav Biomed Mater. 2016;61:328–333. doi: 10.1016/j.jmbbm.2016.04.014. [ DOI ] [ PubMed ] [ Google Scholar ]
73. Schriwer C., Skjold A., Gjerdet N.R., Øilo M. Monolithic zirconia dental crowns. Internal fit, margin quality, fracture mode and load at fracture. Dent Mater. 2017;33:1012–1020. doi: 10.1016/j.dental.2017.06.009. [ DOI ] [ PubMed ] [ Google Scholar ]
74. Rohr N., Märtin S., Fischer J. Correlations between fracture load of zirconia implant supported single crowns and mechanical properties of restorative material and cement. Dent Mater J. 2018;37:222–228. doi: 10.4012/dmj.2017-111. [ DOI ] [ PubMed ] [ Google Scholar ]
75. Tsuyuki Y., Sato T., Nomoto S., Yotsuya M., Koshihara T. Effect of occlusal groove on abutment, crown thickness, and cement-type on fracture load of monolithic zirconia crowns. Dent Mater J. 2018;7:843–850. doi: 10.4012/dmj.2017-350. [ DOI ] [ PubMed ] [ Google Scholar ]
76. Moilanen P., Hjerppe J., Lassila L.V.J.N.T. Fracture strength and precision of fit of implant-retained monolithic zirconia crowns. J Oral Implant. 2018;44:330–334. doi: 10.1563/aaid-joi-D-17-00249. [ DOI ] [ PubMed ] [ Google Scholar ]
77. Lameira D.P., WABE Silva, Silva F.A.E., De Souza G.M. Fracture strength of aged monolithic and bilayer zirconia-based crowns. Biomed Res Int. 2015;15 doi: 10.1155/2015/418641. Article ID 418641, 7 pages. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
78. Johansson C., Kmet G., Rivera J., Larsson C., Vult Von Steyern P. Fracture strength of monolithic all-ceramic crowns made of high translucent yttrium oxide-stabilized zirconium dioxide compared to porcelain-veneered crowns and lithium disilicate crowns. Acta Odontol Scand. 2014;72:145–153. doi: 10.3109/00016357.2013.822098. [ DOI ] [ PubMed ] [ Google Scholar ]
79. Bankoğlu Güngör M., Karakoca Nemli S. Fracture resistance of CAD-CAM monolithic ceramic and veneered zirconia molar crowns after aging in a mastication simulator. J Prosthet Dent. 2018;119:473–480. doi: 10.1016/j.prosdent.2017.05.003. [ DOI ] [ PubMed ] [ Google Scholar ]
80. AFNE Reis, Ramos G.F., Campos T.M.B., Prado P.H.C.O., Vasconcelos G., Borges ALS de M.R. The performance of sol-gel silica coated Y-TZP for veneered and monolithic dental restorations. J Mech Behav Biomed Mater. 2019;90:515–522. doi: 10.1016/j.jmbbm.2018.09.023. [ DOI ] [ PubMed ] [ Google Scholar ]
81. Nishioka G., Prochnow C., Firmino A., Amaral M., Bottino M.A., Valandro LF RM de M. Fatigue strength of several dental ceramics indicated for CAD-CAM monolithic restorations. Braz Oral Res. 2018;32:e53. doi: 10.1590/1807-3107bor-2018.vol32.0053. [ DOI ] [ PubMed ] [ Google Scholar ]
82. Pereira G.K.R., Guilardi L.F., Kiara S., Kleverlaan C.J., Rippe M.P., Valandro L.F. Mechanical reliability, fatigue strength and survival analysis of new polycrystalline translucent zirconia ceramics for monolithic restorations. J Mech Behav Biomed Mater. 2018;85:57–65. doi: 10.1016/j.jmbbm.2018.05.029. [ DOI ] [ PubMed ] [ Google Scholar ]
83. Almansour H.M., Alqahtani F. The effect of in vitro aging and fatigue on the flexural strength of monolithic the effect of in vitro aging and fatigue on the flexural strength of monolithic high-translucency zirconia restorations. J Contemp Dent Pr. 2018;19:867–873. [ PubMed ] [ Google Scholar ]
84. Camposilvan E., Leone R., Gremillard L., Sorrentino R., Zarone F., Ferrari M. Aging resistance, mechanical properties and translucency of different yttria-stabilized zirconia ceramics for monolithic dental crown applications. Dent Mater. 2018;34:879–890. doi: 10.1016/j.dental.2018.03.006. [ DOI ] [ PubMed ] [ Google Scholar ]
85. Weigl P., Sander A., Wu Y., Felber R., Lauer H., Rosentritt M. In-vitro performance and fracture strength of thin monolithic zirconia crowns. J Adv Prosthodont. 2018;10:79–84. doi: 10.4047/jap.2018.10.2.79. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
86. Ozer F., Naden A., Turp V., Mante F. Effect of thickness and surface modifications on flexural strength of monolithic zirconia. J Prosthet Dent. 2018;119:987–993. doi: 10.1016/j.prosdent.2017.08.007. [ DOI ] [ PubMed ] [ Google Scholar ]
87. Sarıkaya I.H.Y. Effects of dynamic aging on the wear and fracture strength of monolithic zirconia restorations. BMC Oral Health. 2018;18(146):1–7. doi: 10.1186/s12903-018-0618-z. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
88. Elsayed A., Meyer G., Wille S.K.M. Influence of the yttrium content on the fracture strength of monolithic zirconia crowns after artificial aging. Quintessence Int. 2019;50:344–349. doi: 10.3290/j.qi.a42097. [ DOI ] [ PubMed ] [ Google Scholar ]
89. Yin R., Lee M., Bae T., Song K. Effect of finishing condition on fracture strength of monolithic zirconia crowns. Dent Mater J. 2019;38:203–210. doi: 10.4012/dmj.2017-391. [ DOI ] [ PubMed ] [ Google Scholar ]
90. Elshiyab S.H., Nawafleh N., Öchsner A., George R. Fracture resistance of implant-supported monolithic crowns cemented to zirconia hybrid-abutments : zirconia-based crowns vs. Lithium disilicate crowns. J Adv Prosthodont. 2018;10:65–72. doi: 10.4047/jap.2018.10.1.65. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
91. Khayat W., Chebib N., Finkelman M., Khayat S., Ali A. Effect of grinding and polishing on roughness and strength of zirconia. J Prosthet Dent. 2017;10:65–72. doi: 10.1016/j.prosdent.2017.04.003. [ DOI ] [ PubMed ] [ Google Scholar ]
92. Prado R.D., Pereira G.K.R., Bottino M.A., Melo R.M.V.L. Effect of ceramic thickness, grinding, and aging on the mechanical behavior of a polycrystalline zirconia. Braz Oral Res. 2017;31 doi: 10.1590/1807-3107BOR-2017.vol31.0082. e82:1–9. [ DOI ] [ PubMed ] [ Google Scholar ]
93. Zucuni C.P., Guilardi L.F., Rippe M.P., Kalil G., Pereira R., Valandro L.F. Fatigue strength of yttria-stabilized zirconia polycrystals: effects of grinding, polishing, glazing, and heat treatment. J Mech Behav Biomed Mater. 2017;75:512–520. doi: 10.1016/j.jmbbm.2017.06.016. [ DOI ] [ PubMed ] [ Google Scholar ]
94. Dapieve K.S., Guilardi L.F., Rippe M.P., Kalil G., Pereira R., Valandro L.F. Mechanical performance of Y-TZP monolithic ceramic after grinding and aging: survival estimates and fatigue strength. J Mech Behav Biomed Mater. 2018;87:288–295. doi: 10.1016/j.jmbbm.2018.07.041. [ DOI ] [ PubMed ] [ Google Scholar ]
95. Ebeid K., Wille S., Salah T., Wahsh M., Zohdy M., Kern M. Evaluation of surface treatments of monolithic zirconia in different sintering stages. J Prosthodont Res. 2018;62:210–217. doi: 10.1016/j.jpor.2017.09.001. [ DOI ] [ PubMed ] [ Google Scholar ]
96. Juntavee N., Attashu S. Effect of different sintering process on flexural strength of translucency monolithic zirconia. J Clin Exp Dent. 2018;10:e821–e830. doi: 10.4317/jced.54749. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
97. Tong H., Tanaka C.B., Kaizer M.R., Zhang Y. Characterization of three commercial Y-TZP ceramics produced for their high-translucency, high-strength and high-surface area. Ceram Int. 2016;42:1077–1085. doi: 10.1016/j.ceramint.2015.09.033. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
98. Elsaka S.E. Optical and mechanical properties of newly developed monolithic multilayer zirconia. J Prosthodont. 2017;28:e279–e284. doi: 10.1111/jopr.12730. [ DOI ] [ PubMed ] [ Google Scholar ]
99. Muñoz E.M., Longhini D., Antonio S.G., Adabo G.L. The effects of mechanical and hydrothermal aging on microstructure and biaxial flexural strength of an anterior and a posterior monolithic zirconia. J Dent. 2017;63:94–102. doi: 10.1016/j.jdent.2017.05.021. [ DOI ] [ PubMed ] [ Google Scholar ]
100. Sulaiman T.A., Abdulmajeed A.A., Donovan T.A., Vallittu P.K., Narhi T.O., Lassila L.V. The effect of staining and vacuum sintering on optical and mechanical properties of partially and fully stabilized monolithic zirconia. Dent Mater J. 2015;34:605–610. doi: 10.4012/dmj.2015-054. [ DOI ] [ PubMed ] [ Google Scholar ]
101. Sulaiman T.A., Abdulmajeed A.A., Shahramian K., Lassila L. Effect of different treatments on the flexural strength of fully versus partially stabilized monolithic zirconia. J Prosthet Dent. 2017;118:216–220. doi: 10.1016/j.prosdent.2016.10.031. [ DOI ] [ PubMed ] [ Google Scholar ]
102. Zhang F., Inokoshi M., Batuk M., Hadermann J., Naert I., Van Meerbeek B. Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations. Dent Mater. 2016;32:e327–e337. doi: 10.1016/j.dental.2016.09.025. [ DOI ] [ PubMed ] [ Google Scholar ]
103. Carrabba M., Keeling A.J., Aziz A., Vichi A., Fabian Fonzar R., Wood D. Translucent zirconia in the ceramic scenario for monolithic restorations: a flexural strength and translucency comparison test. J Dent. 2017;60:70–76. doi: 10.1016/j.jdent.2017.03.002. [ DOI ] [ PubMed ] [ Google Scholar ]
104. Vichi A., Sedda M., Fabian Fonzar R., Carrabba M., Ferrari M. Comparison of contrast ratio, translucency parameter, and flexural strength of traditional and “augmented translucency” zirconia for CEREC CAD/CAM system. J Esthet Restor Dent. 2016;28:S32–S39. doi: 10.1111/jerd.12172. [ DOI ] [ PubMed ] [ Google Scholar ]
105. Candido L.M., Miotto L.N., Fais L.M.G., Cesar P.F., Pinelli L.A.P. Mechanical and surface properties of monolithic zirconia. Oper Dent. 2018:119–128. doi: 10.2341/17-019-L. [ DOI ] [ PubMed ] [ Google Scholar ]
106. Zhang Y., Lee J.J., Srikanth R., Lawn B.R. Edge chipping and flexural resistance of monolithic ceramics. Dent Mater. 2013;29:1201–1208. doi: 10.1016/j.dental.2013.09.004. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
107. Yan J., Kaizer M.R., Zhang Y. Load-bearing capacity of lithium disilicate and ultra-translucent zirconias. J Mech Behav Biomed Mater. 2018;88:170–175. doi: 10.1016/j.jmbbm.2018.08.023. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
108. Basso G.R., Moraes R.R., Borba M., Griggs J.A., Della Bona A. Flexural strength and reliability of monolithic and trilayer ceramic structures obtained by the CAD-on technique. Dent Mater. 2015;31:1453–1459. doi: 10.1016/j.dental.2015.09.013. [ DOI ] [ PubMed ] [ Google Scholar ]
109. Sakai T., Sato T., Hisanaga R., Shinya A., Takemoto S., Yoshinari M. Optical properties and flexural strength of translucent zirconia layered with high-translucent zirconia. Dent Mater J. 2019;38:368–377. doi: 10.4012/dmj.2018-157. [ DOI ] [ PubMed ] [ Google Scholar ]
110. Ozer F., Naden A., Turp V., Mante F., Sen D., Blatz M.B. Effect of thickness and surface modifications on flexural strength of monolithic zirconia. J Prosthet Dent. 2017;119:987–993. doi: 10.1016/j.prosdent.2017.08.007. [ DOI ] [ PubMed ] [ Google Scholar ]
111. Kumchai H., Juntavee P., Sun A.F., Nathanson D. Effect of glazing on flexural strength of full-contour zirconia. Int J Dent. 2018 doi: 10.1155/2018/8793481. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
112. Chougule K.J., Wadkar A. An in vitro comparative evaluation of flexural strength of monolithic zirconia after surface alteration utilising two different techniques. J Clin Diagn Res. 2017;11:ZC20–ZC23. doi: 10.7860/JCDR/2017/25177.10361. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
113. Nam M., Park M. Changes in the flexural strength of translucent zirconia due to glazing and low-temperature degradation. J Prosthet Dent. 2018;120 doi: 10.1016/j.prosdent.2018.07.017. 969.e1-969.e6. [ DOI ] [ PubMed ] [ Google Scholar ]
114. Schatz C., Strickstrock M., Roos M., Edelhoff D., Eichberger M., Zylla I.M. Influence of specimen preparation and test methods on the flexural strength results of monolithic zirconia materials. Materials (Basel) 2016;9:E180. doi: 10.3390/ma9030180. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
115. Zucuni C.P., Guilardi L.F.F., Rippe M.P.P., Pereira G.K.R., Valandro L.F.F. Fatigue strength of yttria-stabilized zirconia polycrystals: effects of grinding, polishing, glazing, and heat treatment. J Mech Behav Biomed Mater. 2017;75:512–520. doi: 10.1016/j.jmbbm.2017.06.016. [ DOI ] [ PubMed ] [ Google Scholar ]
116. Chevalier J., Cales B., Drouin J.M. Low-temperature aging of Y-TZP ceramics. J Am Ceram Soc. 1999;82:2150–2154. [ Google Scholar ]
117. Lughi V., Sergo V. Low temperature degradation -aging- of zirconia: a critical review of the relevant aspects in dentistry. Dent Mater. 2010;26:807–820. doi: 10.1016/j.dental.2010.04.006. [ DOI ] [ PubMed ] [ Google Scholar ]
118. Alghazzawi T.F., Lemons J., Liu P.R., Essig M.E., Bartolucci A.A., Janowski G.M. Influence of low-temperature environmental exposure on the mechanical properties and structural stability of dental zirconia. J Prosthodont. 2012;21:363–369. doi: 10.1111/j.1532-849X.2011.00838.x. [ DOI ] [ PubMed ] [ Google Scholar ]
119. Stawarczyk B., Frevert K., Ender A., Roos M., Sener B., Wimmer T. Comparison of four monolithic zirconia materials with conventional ones: contrast ratio, grain size, four-point flexural strength and two-body wear. J Mech Behav Biomed Mater. 2016;59:128–138. doi: 10.1016/j.jmbbm.2015.11.040. [ DOI ] [ PubMed ] [ Google Scholar ]
120. Alghazzawi T.F., Janowski G.M. Correlation of flexural strength of coupons versus strength of crowns fabricated with different zirconia materials with and without aging. J Am Dent Assoc. 2015;146:904–912. doi: 10.1016/j.adaj.2015.06.006. [ DOI ] [ PubMed ] [ Google Scholar ]
121. Flinn B.D., Raigrodski A.J., Mancl L.A., Toivola R., Kuykendall T. Influence of aging on flexural strength of translucent zirconia for monolithic restorations. J Prosthet Dent. 2017;117:303–309. doi: 10.1016/j.prosdent.2016.06.010. [ DOI ] [ PubMed ] [ Google Scholar ]
122. Adabo G.L., Mariscal E.M., Hatanaka G.R. Flexural strength and microstructure of anterior/monolithic zirconia after low-temperature aging. Dent Mater. 2015;31:e48–e49. [ Google Scholar ]
123. Guilardi L.F., Pereira G.K.R., Gündel A., Rippe M.P., Valandro L.F. Surface micro-morphology, phase transformation, and mechanical reliability of ground and aged monolithic zirconia ceramic. J Mech Behav Biomed Mater. 2017;65:849–856. doi: 10.1016/j.jmbbm.2016.10.008. [ DOI ] [ PubMed ] [ Google Scholar ]
124. Pereira G.K.R., Silvestri T., Camargo R., Rippe M.P., Amaral M., Kleverlaan C.J. Mechanical behavior of a Y-TZP ceramic for monolithic restorations: effect of grinding and low-temperature aging. Mater Sci Eng C. 2016;63:70–77. doi: 10.1016/j.msec.2016.02.049. [ DOI ] [ PubMed ] [ Google Scholar ]
125. Dehestani M., Adolfsson E. Phase stability and mechanical properties of zirconia and zirconia composites. Int J Appl Ceram Technol. 2013;10:129–141. [ Google Scholar ]
126. Nakamura K., Harada A., Kanno T., Inagaki R., Niwano Y., Milleding P. The influence of low-temperature degradation and cyclic loading on the fracture resistance of monolithic zirconia molar crowns. J Mech Behav Biomed Mater. 2015;47:49–56. doi: 10.1016/j.jmbbm.2015.03.007. [ DOI ] [ PubMed ] [ Google Scholar ]
127. Leone R., Sorrentino R., Camposilvan E., Chevalier J., Zarone F., Ferrari M. In vitro aging and mechanical properties of translucent monolithic zirconia. Dent Mater. 2016;32:e98. doi: 10.1016/j.dental.2018.03.006. [ DOI ] [ PubMed ] [ Google Scholar ]
128. Bergamo E., da Silva W., Cesar P., Del Bel Cury A. Fracture load and phase transformation of monolithic zirconia crowns submitted to different aging protocols. Oper Dent. 2016;41:E118–E130. doi: 10.2341/15-154-L. [ DOI ] [ PubMed ] [ Google Scholar ]
129. Salihoglu Yener E., Ozcan M., Kazazoglu E. A comparative study of biaxial flexural strength and Vickers microhardness of different zirconia materials: effect of glazing and thermal cycling. Brazilian Dent Sci. 2015;18:19. [ Google Scholar ]
130. Mitov G., Anastassova-Yoshida Y., Nothdurft F.P., von See C., Pospiech P. Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns. J Adv Prosthodont. 2016;8:30–36. doi: 10.4047/jap.2016.8.1.30. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
131. Nordahl N., Vult von Steyern P., Larsson C. Fracture strength of ceramic monolithic crown systems of different thickness. J Oral Sci. 2015;57:255–261. doi: 10.2334/josnusd.57.255. [ DOI ] [ PubMed ] [ Google Scholar ]
132. Bankoğlu Güngör M., Karakoca Nemli S. Fracture resistance of CAD-CAM monolithic ceramic and veneered zirconia molar crowns after aging in a mastication simulator. J Prosthet Dent. 2017;119:473–480. doi: 10.1016/j.prosdent.2017.05.003. [ DOI ] [ PubMed ] [ Google Scholar ]
133. Preis V., Behr M., Hahnel S., Handel G., Rosentritt M. In vitro failure and fracture resistance of veneered and full-contour zirconia restorations. J Dent. 2012;40:921–928. doi: 10.1016/j.jdent.2012.07.010. [ DOI ] [ PubMed ] [ Google Scholar ]
134. Alshahrani F.A., Yilmaz B., Seidt J.D., McGlumphy E.A., Brantley W.A. A load-to-fracture and strain analysis of monolithic zirconia cantilevered frameworks. J Prosthet Dent. 2017;118:752–758. doi: 10.1016/j.prosdent.2017.01.028. [ DOI ] [ PubMed ] [ Google Scholar ]
135. Villefort R.F., Amaral M., Pereira G.K.R., Campos T.M.B., Zhang Y., Bottino M.A. Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses. Dent Mater. 2017;33:e155–e164. doi: 10.1016/j.dental.2016.12.010. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
136. Lopez-Suarez C., Rodriguez V., Pelaez J., Agustin-Panadero R., Suarez M.j. Comparative fracture behavior of monolithic and veneered zirconia posterior fixed dental prostheses. Dent Mater J. 2017;36:816–821. doi: 10.4012/dmj.2016-391. [ DOI ] [ PubMed ] [ Google Scholar ]
137. Feitosa S., Patel D., Borges A., Alshehri E., Bottino M., Özcan M. Effect of cleansing methods on saliva-contaminated zirconia—an evaluation of resin bond durability. Oper Dent. 2015;40:163–171. doi: 10.2341/13-323-L. [ DOI ] [ PubMed ] [ Google Scholar ]
138. Sharafeddin F., Shoale S. Effects of universal and conventional MDP primers on the shear bond strength of zirconia ceramic and nanofilled composite resin. J Dent (Shiraz, Iran) 2018;19:48–56. [ PMC free article ] [ PubMed ] [ Google Scholar ]
139. Rosentritt M., Preis V., Behr M., Hahnel S., Handel G., Kolbeck C. Two-body wear of dental porcelain and substructure oxide ceramics. Clin Oral Invest. 2012;16:935–943. doi: 10.1007/s00784-011-0589-9. [ DOI ] [ PubMed ] [ Google Scholar ]
140. Sasse M., Kern M. Survival of anterior cantilevered all-ceramic resin-bonded fixed dental prostheses made from zirconia ceramic. J Dent. 2014;42:660–663. doi: 10.1016/j.jdent.2014.02.021. [ DOI ] [ PubMed ] [ Google Scholar ]
141. Stawarczyk B., Frevert K., Ender A., Roos M., Sener B., Wimmer T. Comparison of four monolithic zirconia materials with conventional ones : contrast ratio, grain size, four-point fl exural strength and two-body wear. J Mech Behav Biomed Mater. 2016;59:128–138. doi: 10.1016/j.jmbbm.2015.11.040. [ DOI ] [ PubMed ] [ Google Scholar ]
142. Aung S., Phyo M., Takagaki T., Kham S. Effects of alumina-blasting pressure on the bonding to super / ultra-translucent zirconia. Dent Mater. 2019;35:730–739. doi: 10.1016/j.dental.2019.02.025. [ DOI ] [ PubMed ] [ Google Scholar ]
143. Inokoshi M., Shimizu H., Nozaki K., Takagaki T., Yoshihara K., Nagaoka N. Crystallographic and morphological analysis of sandblasted highly translucent dental zirconia. Dent Mater. 2018;34:508–518. doi: 10.1016/j.dental.2017.12.008. [ DOI ] [ PubMed ] [ Google Scholar ]
144. Putra A., Chung K.H., Flinn B.D., Kuykendall T., Zheng C., Harada K. Effect of hydrothermal treatment on light transmission of translucent zirconias. J Prosthet Dent. 2017;118:422–429. doi: 10.1016/j.prosdent.2016.10.024. [ DOI ] [ PubMed ] [ Google Scholar ]
145. Xie H., Cheng Y., Chen Y., Qian M., Xia Y., Chen C. Improvement in the bonding of Y-TZP by room-temperature ultrasonic HF etching. J Adhes Dent. 2017;19:425–433. doi: 10.3290/j.jad.a39278. [ DOI ] [ PubMed ] [ Google Scholar ]
146. Torabi Ardekani K., Ahangari A.H., Farahi L. Marginal and internal fit of CAD/CAM and slip-cast made zirconia copings. J Dent Res Dent Clin Dent Prospects. 2012;6:42–48. doi: 10.5681/joddd.2012.010. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
147. Moon J.E., Kim S.H., Lee J.B., Han J.S., Yeo I.S., Ha S.R. Effects of airborne-particle abrasion protocol choice on the surface characteristics of monolithic zirconia materials and the shear bond strength of resin cement. Ceram Int. 2016;42:1552–1562. [ Google Scholar ]
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