Ultra-translucent zirconia processing and aging effect on microstructural, optical, and mechanical properties

Araújo-Júnior, Everardo N.S. de; Bergamo, Edmara Tatiely Pedroso; Bastos, Tiago M.C.; Jalkh, Ernesto B. Benalcázar; Lopes, António; Monteiro, K.N.; César, Paulo Francisco; Tognolo, Fernanda C.; Migliati, Rafael; Tanaka, Ricardo; Bonfante, Estevam Augusto

doi:10.1016/j.dental.2022.02.016

Cited by 31 publications

(11 citation statements)

References 46 publications

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“…The flexural strength results for 5Y-PSZ show the similar values when the specimens were not alumina particle air-abraded compared to existing studies [ 26 , 27 ]. This confirms the correct production of the specimen and the course of the test.…”

Section: Discussionsupporting

confidence: 69%

Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

2022

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The aim of this study was to analyze the influence of different surface treatments and the corresponding surface roughness on the ball-on-three-balls test and piston-on-three-balls test for measuring flexural strength 3Y-TZP and 5Y-PSZ. Additionally, the influence of cutting the material into the specimens when pre-sintered or fully sintered was analyzed. A total of 120 specimens for each material group, 3Y-TZP zirconia (Katana HT, Kuraray) and the 4 different layers of multilayered 5Y-PSZ zirconia (Katana UTML, Kuraray), were produced. The used material was cut into half of the specimens in a fully sintered stage, the other half was cut when pre-sintered. Each subgroup was divided into 3 different surface treatment groups being air abraded with 50 µm alumina particles at 1 bar pressure, ground with 600 SiC paper or polished up to 1 µm with a polycristalline diamond suspension. These were then analyzed by X-ray diffraction (XRD) (N = 3) and tested for flexural strength using the ball-on-three-balls test (N = 10) or piston-on-three-balls test (N = 10). For 3Y-TZP groups different surface roughness did not result in statistically significant differences in flexural strength but cutting the specimens in fully sintered state significantly reduced flexural strength of 1133 ± 109 to 741 ± 81 MPa. For 5Y-PSZ groups air abrasion of the specimens with alumina particles significantly reduced the flexural strength of 562 ± 68 MPa to 358 ± 58 MPa. Cutting and surface treatment in pre-sintered or fully sintered state had no significant influence. Flexural strength testing with the ball-on-three-balls test resulted in about 20% higher strengths compared to the piston-on-three-balls test. Results of both tests showed the same tendencies when compared.

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Section: Discussionsupporting

confidence: 69%

Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

2022

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“…Previous research on 3Y-TZP, 4Y-TZP, and 5Y-PSZ with different LTD treatment times showed that the biaxial flexural strength of 5Y-PSZ decreased from 618 MPa to 544 MPa after hydrothermal aging treatment for 160 h, but that the strength of commercial 5Y-PSZ hydrothermally aged for 20 h was 612 MPa without any significant effect of the aging protocol [22]. 5Y-PSZ contains a higher fraction of the cubic phase, which is maintained unchanged regardless of the sintering rate and the final temperature [39], and the cubic phase may confer better resistance to LTD [38].…”

Section: Discussionmentioning

confidence: 90%

“…So far, the inverse relationship between the mechanical and optical properties of zirconia is still a dominant issue, and the choice of 5Y-PSZ material is a compromise between strength and esthetics. Considering the strength of the material, 5Y-PSZ is inferior to 3Y-TZP, and the recommended indication is limited to short-span anterior prostheses [22].…”

Section: Discussionmentioning

confidence: 99%

Aging resistance of highly translucent zirconia ceramics with rapid sintering

et al. 2023

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Purpose: Rapid sintering technology has become one of the most direct methods for shortening the manufacturing time of zirconia restorations. This study aimed to explore the aging resistance of rapid-sintered 5 mol% yttria-partially-stabilized zirconia (5Y-PSZ). Methods: Specimens were made from two types of 5Y-PSZ material and subjected to rapid sintering (RS) and conventional sintering (CS). After in vitro aging for 5 h, morphology observation, grain size measurement, and phase composition analysis were performed. The mechanical properties were evaluated by biaxial, three-point flexural tests, and the Vickers microhardness test. Results were analyzed by 3-way ANOVA. Results: Both the RS group and the CS group had a dense microstructure. The tested zirconia ceramics had different grain sizes, which were affected by the interaction between the sintering method and aging. Both groups revealed the same characteristic peaks of the cubic phase after aging. Regardless of the sintering method used, there was no significant difference in the mechanical properties of the tested zirconia before and after aging. Conclusion:The rapid-sintered 5Y-PSZ materials had a microstructure, phase composition and mechanical properties similar to those of conventional sintered materials. The characteristics of the materials prepared using the two sintering methods did not change significantly after aging.

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“…The LTD treatment activates and accelerates the t-to-m phase transformation, associated with the deterioration of surfaces exposed to moisture. In Pereira et al’s systematic review [ 29 ], the authors reported that the m-phase contents were about 0–14% before aging and 11–40% after accelerated aging for 10 h. An increase in translucency, explained by the reduction of light scattering from the boundaries of the cubic phase particles [ 41 ], was also observed. However, for super-high translucency zirconia, the presence of the cubic phase induces an insignificant hydrothermal degradation, with a minor increase in translucency; the lack of phase transformation and the coarser microstructure determine lower mechanical properties for this zirconia.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Polishing, Glazing, and Aging on Optical Characteristics of Multi-Layered Dental Zirconia with Different Degrees of Translucency

Toma

Vasiliu

Porojan

2023

JFB

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(1) Background: Considering that the appearance of a dental material is an important factor that contributes to the success of prosthetic restorations. The purpose of this study is to investigate the optical properties and color changes among the layers of three commercial zirconias, to compare the aspect of the polished and glazed surfaces before and after aging and to evaluate the effects of hydrothermal degradation on their aesthetics. (2) Methods: Forty-eight plate-shaped samples were sectioned from presintered blocks of each multilayer translucent zirconia with different Yttrium content: Ceramill Zolid fx ML (5 mol%) = CeZ, STML (4 mol%) = STM, IPS e.maxZirCAD CEREC/in Lab MT Multi (4 mol% + 5 mol%) = IPZ. The samples were sintered according to the recommendation of each manufacturer, and half (24) of them were polished and the other half (24) glazed on one of the surfaces. Each type was equally divided into one control and one aging group, and, for each material, this resulted in four groups (n = 12): polished-control, polished-autoclaved glazed-control, and glazed-autoclaved. The artificial aging was carried out with an autoclave and distilled water at 134 °C, 0.2 MPa for 1 h, and for optical parameters (TP, CR, OP) and color change (ΔE*) measurements on a black and white background in a CIE L*a*b* color system, a spectrophotometer was used. The specimens were evaluated in incisal, cervical, and medium areas on polished and glazed samples before and after the aging stage. Statistical analysis was achieved with a two-way ANOVA test, the unpaired t-test, and the paired t-test. (3) Results: Before and after aging, the mean TP values for polished samples were higher than the glazed ones. After aging, the mean TP values increased for all groups (except polished CeZ), and significant differences were reported for polished STM, IPZ. After LTD, the opalescence registered an increase for almost all groups (except polished CeZ, polished and glazed IPZ—medium area), and significant differences were reported for almost all groups (except STM—incisal, IPZ—cervical, medium areas). The levels of color change were between extremely slight to perceivable. (4) Conclusions: Optical properties of the selected multilayer zirconia were influenced by polishing and glazing as surface treatment and affected by artificial aging (CeZ the least); perceivable color changes for polished STM, IPZ were detected.

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Ultra-translucent zirconia processing and aging effect on microstructural, optical, and mechanical properties

Cited by 31 publications

References 46 publications

Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

Aging resistance of highly translucent zirconia ceramics with rapid sintering

The Effect of Polishing, Glazing, and Aging on Optical Characteristics of Multi-Layered Dental Zirconia with Different Degrees of Translucency

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