Table 2.
Studies investigating mechanical properties of monolithic zirconia specimens. Studies are presented in ascending chronological order.
| Authors | Zirconia system | Test type/Methodology | Results | |
|---|---|---|---|---|
| Zhang et al. (2013) [106] | Experimental monolithic zirconia | Chipping (Vickers) and flexural strength (3- and 4- point bending, specimens cemented on composite), crosshead speed 1 mm min−1 | Monolithic restorations exhibited superior fracture resistance relative to their porcelain-veneered counterparts and higher resistance to failure than lithium disilicate glass–ceramics | |
| Basso et al. (2015) [108] | - IPS e.max ZirCAD | Flexural strength (3-point bending), monolithic and trilayer (zirconia core, fusion glass, veneer) specimens, crosshead-speed 0.5 mm min−1. | No significant differences between monolithic and trilayer structures | |
| Sulaiman et al. (2015) [100] | - Prettau (PSZ) | Biaxial strength test (piston-on-three balls), crosshead-speed 1 mm min−1. | Unstained PSZ had significantly higher strength than unstained FSZ. After staining both had similar strength. | |
| - Prettau, Anterior (FSZ) | ||||
| Schatz et al. (2016) [114] | - Ceramill Zolid (C) | Biaxial, 3-point, and 4-point flexural strength testing, crosshead speed 1 mm min−1 | No significant difference among the different ceramics. | |
| - Zenostar Zr (Z) | The 4-point flexural strength testing shows the lowest flexural strength data; biaxial test method the highest. | |||
| - DD Bio ZX2 | ||||
| Tong et al. (2016) [97] | - Zpex (High-Translucency) | Fracture toughness test (edge chipping), Vickers hardness test and flexural strength test (4-point bending) of specimens, crosshead-speed 0.1 mm min−1. | High-strength Y-TZP exhibited the best and high-translucency the worst mechanical properties. The opposite was for the translucency. | |
| - TZ-3YS-E (High-Strength) | ||||
| - TZ-3Y-E (High-Surface Area) | ||||
| Vichi et al. (2016) [104] | - IPS e.max Zir-CAD | Flexural strength (3-point bending test), crosshead-speed 1 mm min−1. | The new “augmented translucency” TZPs (VITA In-Ceram YZ HT and inCoris TZI) specimens showed higher translucency and similar flexural strength than “traditional” TZPs. | |
| - inCoris ZI | ||||
| - inCoris TZI | ||||
| - In-Ceram YZ | ||||
| - In-Ceram YZ HT | ||||
| Zhang et al. (2016) [102] | - TZ-3YE | Flexural strength (4-point bending), crosshead speed 1 mm min−1, hardness (Vickers indentation), toughness (Single-etchV-notch beam) | Increasing the yttria content decreased the fracture toughness and flexural strength but increased resistance to aging. The addition of La2O3 decreased the flexural strength but did not influence hardness and toughness. | |
| - Zpex | ||||
| - Zpex Smile | ||||
| - Experimental monolithic 1 | ||||
| - Experimental monolithic 2 | ||||
| Carrabba et al. (2017) [103] | - Aadva Standard Translucency [ST] | Flexural strength (3-point bending), crosshead-speed 1 mm min−1. | There was an inverse relationship between strength and translucency for the materials tested. Addition of Al2O3 and increased yttria content strongly downgraded the mechanical properties. | |
| - Aadva Enamel Intensive [EI] | ||||
| - Aadva Natural Translucency [NT] | ||||
| Chougule et al. (2017) [112] | Lava | Flexural strength (3-point bending test), crosshead-speed of 0.5 mm min−1. | Flexural strength was significantly higher after glazing but not after polishing. | |
| Church et al. (2017) [64] | BruXZir Shaded 16 | Flexural strength (3-point bending), crosshead-speed of 1 mm min−1. | The flexural strength of highly translucent zirconia materials was significantly higher than those of lithium disilicate. No statistically significant differences among the various monolithic ceramics were recorded. | |
| BruXZir HT | ||||
| Lava Plus | ||||
| inCoris TZI C | ||||
| Elsaka et al. (2017) [98] | - Ceramill Zolid FX | Flexural strength (3-point bending test), crosshead-speed 0.5 mm min−1, fracture toughness (3-point bending test), crosshead speed 0.5 mm min−1, Vickers hardness | ZT monolithic zirconia revealed higher flexural strength and fracture toughness compared with CZF and PA | |
| - Multilayer (CZF) | CZF revealed higher hardness compared with PA and ZT. | |||
| - Prettau Anterior (PA) | ||||
| - Zenostar T (ZT) | ||||
| Munoz et al. (2017) [99] | - Prettau Anterior | Biaxial flexural strength, crosshead-speed 1 mm min−1 | Pretatu Anterior presented the lowest strength which was significantly reduced by mechanical and thermomechanical cycling | |
| - Prettau | Hydrothermal degradation; mechanical cyclic load; mechanical cyclic plus hydrothermal degradation (H + M); non-treated specimens (control group). | |||
| - ICE Zirkon | ||||
| Ozer et al. (2017) [110] | - Pretau | Biaxial flexural strength (piston-on-three balls strength), crosshead-speed 0.5 mm min−1 | Statistically higher strength of the thicker specimens, but both had higher than the reported masticatory forces Airborne-particle abrasion increased the flexural strength of monolithic zirconia. Grinding did not affect flexural strength if subsequently polished | |
| Disc specimens of 0.8 and 1.3 mm : | ||||
| - untreated (control) | ||||
| - airborne-particle abrasion | ||||
| - grinding with a diamond rotary instrument followed by polishing. | ||||
| Sulaiman et al. (2017) [101] | - Prettau | Flexural strength (3-point bending), crosshead-speed 0.5 mm min−1. | The strength of FSZ was approximately half that of PSZ. Staining enhanced the strength of FSZ, with no effect on PSZ. Airborne-particle abrasion lowered the strength of FSZ, while enhanced that of PSZ. Artificial aging had no effect on the flexural strength of either. | |
| - Prettau, Anterior | ||||
| - ICE Zircon | ||||
| Kumchai et al. (2018) [111] | - inCoris TZI | Flexural strength (3-point bending test), crosshead-speed of 0.5 mm min−1. | Overglazing significantly decreased the flexural strength. | |
| - Prettau | - heat treated (glazed with no paste) | Heat treatment had no significant effect on the flexural strength. There was no significant difference in the flexural strengths of different brands | ||
| - Zirlux FC | - overglazed (use of glaze paste) | |||
| Two different glaze materials: | ||||
| - Zirkonzahn glaze paste + liquid | ||||
| - Zirlux FC glaze paste + liquid | ||||
| Sakai et al. (2019) [109] | - translucent TZP (Zpex, Tosoh) | Biaxial flexural strength, Monolithic zirconia materials of different tranclucencies were adhered and evaluated as a method for more accurate colour simulation. | Flexural strength was not affected negatively. | |
| - high- translucency PSZ (ZpexSmile, Tosoh) | ||||
| Reis et al. (2019) [80] | Vita In Ceram YZ | Nano-indentation (hardness evaluation), pulse-echo (elastic modulus), scratch test | Silica infiltration increased the hardness but reduced the fracture toughness. Adhesion of feldspathic porcelain to non-infiltrated zirconia proved to be stronger | |
| - monolithic zirconia | ||||
| - silica infiltrated monolithic zirconia(via the sol-gel method) | ||||
| - zirconia + feldspathic porcelain of two thicknesses | ||||
| - silica infiltrated zirconia + feldspathic porcelain of two thicknesses | ||||
| Juntavee et al. (2018) [96] | Y-TZP, VITA YZ HT color® | Flexural strength (3-point bending), crosshead speed 1 mm min−1 | Increasedsintering temperature and prolonged sintering holding time was correlated with higher flexural strength | |
| Sintering at different temperatures: | Sintered holding times: | |||
| - decreasing | - shortening | |||
| - regular | - regular | |||
| - increasing | - prolonged | |||
| Yan et al. (2018) [107] | dental zirconias (the Luxisse series) | Flexural strength (piston-on-three balls) ceosshead speed 1 mm min−1, specimens bonded to a dentin-like substrate | The load-bearing capacity of the lithium disilicate ceramic presented higher values than 5Y-TZP. | |
| - 5Y-PSZ | ||||
| - 4Y-PSZ | ||||
| - 3Y- TZP (control) | ||||
| IPS e.max CAD | ||||
| Candido et al. (2018) [105] | - Prettau Zircon | Flexural strength (four-point bending) crosshead speed 1 mm min−1 | Flexural strength did not present significant difference between monolithic and conventional zirconia. | |
| - ICE Zirkon Transluzent | ||||
| - BloomZir | ||||
| Nishioka et al. (2018) [81] | - Feldspathic ceramic (VITABLOCS Mark II) | Flexural strength (piston-on-three balls) under water (staircase approach :100,000 cycles at 10 Hz) | The highly translucent polycrystalline zirconia can withstand a higher cyclic load before failure | |
| - Polymer-infiltrated ceramic network (VITA Enamic) | ||||
| - Zirconia-reinforced lithium silicate glass-ceramic (VITA Suprinity) | ||||
| - Lithium disilicate glass-ceramic (IPS e.Max CAD) | ||||
| - High translucent yttrium partially stabilized tetragonal zirconia polycrystals (Zirconia YZ HT) | ||||
| Ozer et al. (2018) [86] | Prettau | Flexural strength (piston-on-three balls), crosshead speed 0.5 mm min−1 (disks of thickness 0.8 mm and 1.3 mm) | 1.3 mm specimens presented significantly higher flexural strength. Airborne-particle abrasion significantly increased the flexural strength. Grinding and polishing didn not affect the flexural strength | |
| - airborne-particle abrasion, 50-mmAl2O3 particles (pressure of 400 kPa, distance of 10 mm) | ||||
| - grinding with a diamond rotary instrument followed by polishing | ||||
| - control | ||||
| Ebeid et al. (2018) [95] | Bruxzir | Biaxial flexural strength (piston-on-three balls), crosshead speed 0.5 mm min−1 | Surface treatment at the pre-sintered was correlated with higher flexural strength | |
| - air-abrasion with Al2O3 50 mm particles | ||||
| - silica coating with 30 mm Rocatec soft particles | ||||
| - control (no surface treatment) | ||||
| - the surface treatments were performed either at the pre-sintered stage or the post-sintered stage | ||||
| Zucuni et al. (2017) [115] | Zenostar blank | Flexural strength (piston-on-three balls), fatigue tests included 20,000 cycles and a frequency of 6 Hz | -polishing after grinding is mandatory in order to avoid strength deterioration | |
| - control | - heat treatment is not a good alternative to polishing | |||
| - grinding | - polishing enhances fatigue | |||
| - polishing | ||||
| - glazing | ||||
| - heat treatment | ||||
| - polishing + heat treatment | ||||
| - polishing + glazing | ||||