Mechanical and microstructural properties of ultra-translucent dental zirconia ceramic stabilized with 5 mol% yttria

Harada, Akio; Shishido, Shunichi; Barkarmo, Sargon; Inagaki, Ryoichi; Kanno, Taro; Örtengren, Ulf; Egusa, Hiroshi; Nakamura, Keisuke

doi:10.1016/j.jmbbm.2020.103974

Cited by 28 publications

(28 citation statements)

References 33 publications

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“…Harada CH 3 . 40 observed phase composition of 5Y-TZP before and after low-temperature degradation. Using backscattered electron image (BSE), 5Y-TZP surfaces were divided into L-region (Ø > 1 µm) and S-region (Ø < 1 µm) by grain sizes.…”

Section: Discussionmentioning

confidence: 81%

Comparison of surface topography and roughness in different yttrium oxide compositions of dental zirconia after grinding and polishing

Shin

Lee

2021

J Adv Prosthodont

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PURPOSE The purpose of this study was to compare the surface roughness, phase transformation, and surface topography of dental zirconia with three different yttrium oxide compositions under same grinding and polishing conditions. MATERIALS AND METHODS Three zirconia disks (IPS e.max ZirCAD LT, MT, MT multi, Ivoclar Vivadent AG, Schaan, Liechtenstein) were selected for experimental materials. Sixty-nine bar-shaped specimens were fabricated as 12.0 × 6.0 × 4.0 mm using a milling machine and glazing was conducted on 12.0 × 6.0 mm surface by same operator. With a custom polishing device, 12.0 × 6.0 mm surfaces were polished under same condition. Surface roughness (Ra[µm]) was measured before grinding (C), after grinding (G), and at every 3 steps of polishing (P1, P2, P3). X-ray diffraction and FE-SEM observation was conducted before grinding, after grinding, and after fine polishing (P3). Statistical analysis of surface roughness was performed using Kruskal-Wallis test and Mann-Whitney-U test was used as a post hoc test (α = .05). RESULTS There were no significant differences of surface roughness between LT, MT, and MM groups. In LT, MT, and MM groups, P3 groups showed significantly lower surface roughness than C groups. X-ray diffraction showed grinding and polishing didn't lead to phase transformation on zirconia surface. In FE-SEM images, growths in grain size of zirconia were observed as yttrium oxide composition increases. CONCLUSION Polished zirconia surface showed clinically acceptable surface roughness, but difference in yttrium oxide composition had no significant influence on the surface roughness. Therefore, in clinical situation, zirconia polishing burs could be used regardless of yttrium oxide composition.

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Section: Discussionmentioning

confidence: 81%

Comparison of surface topography and roughness in different yttrium oxide compositions of dental zirconia after grinding and polishing

Shin

Lee

2021

J Adv Prosthodont

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“…Cubic grain formation led to larger grain size and fewer grain boundaries so light scattering at these small amounts of grain boundaries enhance the translucency. 27,41 CSP and especially CSM, which are monolithic zirconia materials with higher cubic phase ratios due to the yttria amount in their content, are expected to show a more homogeneous grain size distribution, but this situation could not be observed when SEM images are examined. This result might be achieved due to the effect of different sintering regimes on grain size and phase type.…”

Section: Pekkanmentioning

confidence: 99%

Effect of sintering regimes and thickness on optical properties of zirconia ceramics for dental applications

Pekkan

2021

Int J Applied Ceramic Tech

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In dentistry, monolithic zirconia restorations have been preferred over all-ceramic restorations in recent years. Translucency is an aesthetic demand in dental restorations, and it can be identified with translucency parameter (TP). Zirconia thickness, Y 2 O 3 content, and sintering conditions are important parameters that influence the translucency of the restorations. It is crucial to investigate monolithic zirconia ceramics under different sintering regimes and reveal the critical parameters for dental restorations. The aim of this study was to determine the optical and microstructural behaviors of monolithic zirconia ceramics containing different amounts of yttria depending on various sintering regimes and thicknesses. Therefore, a conventional zirconia CopranZri (CZI) and two monolithic zirconia materials, CopraSupreme (CSP), CopraSmile (CSM) were used. Slow, normal, speed, and translucency sintering regimes with thicknesses of 0.7, 1.0, 1.3 mm were selected. TP of the specimens was calculated, and statistical analyses were performed by using one-way ANOVA and Tukey-Kramer post hoc tests. Characterization of the specimens was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) techniques. The results showed that the effect of different sintering programs is more critical for CSP and CSM in terms of translucency variations and translucency program led to the most grain growth.

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“…The measured biaxial strength as well as the estimated 3-point and 4-point flexural strengths were at the top of currently available strengths of high-strength conventional 3Y-TZP [26,41] and overcame the strength of dental 3Y-TZP ceramics with improved translucency and even mostly surpassed the dental low translucent high-strength zirconia (i.e. opaque dental zirconia with alumina doping) [12,30,31,33,34,75,76]. Moreover, it must be noted that all the strength results in this study were obtained from tests performed on samples with no surface treatment after sintering (i.e.…”

Section: Mechanical and Optical Propertiesmentioning

confidence: 78%

“…The presence of the cubic phase (c-ZrO 2 ) in the tetragonal structure reduces the light scattering at grain boundaries and the tetragonal/cubic zirconia ceramics thus exhibit higher translucency compared with pure tetragonal zirconia ceramics. On the other hand, the c-ZrO 2 cannot undergo the transformation toughening effect, and the strength of tetragonal/cubic zirconia ceramics is lowered to 50-75% of the conventional high-strength tetragonal 3Y-TZP ceramics that can reach up to 1200 MPa in the 3-point bending [13,[33][34][35]. Recently, gradient multilayer pre-sintered discs have been developed with yttria content changing from 5 mol% at the top to 3 mol% at the bottom of the disc [36].…”

Section: Introductionmentioning

confidence: 99%

Gelcast Zirconia Ceramics With High Strength and Simultaneously High Translucency for Dental Applications

Kaštyl

Chlup

Pouchlý

et al. 2021

Preprint

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Translucent zirconia represents a favourite material for monolithic ceramic dental restorations. However, materials approaches employed so far to improve the translucency of zirconia ceramics are accompanied by a significant decline in strength. Thus, we aimed to develop dental 3Y-TZP ceramics that can provide excellent strength and, simultaneously, enhanced translucency. In this investigation, machinable tetragonal zirconia ceramics based on fine mesostructured zirconia particles stabilized with 3 mol% of yttria and prepared by the gelcasting processing method were developed. Properties of sintered samples were characterised, namely: shrinkage, density, structure, surface roughness, hardness, biaxial strength, and total forward transmittance. Zirconia ceramics with an average biaxial strength of 1184 MPa and a total forward transmittance of 46.7% for a 0.5 mm thick sample at a wavelength of 600 nm were obtained. These ceramics exhibited homogeneous structure with grains sizes up to 620 nm and purely tetragonal phase composition. The developed ceramics provided a favourable combination of high translucency comparable even with the mixed cubic/tetragonal structure of a common 4Y-TZP, and very high strength that is achievable only in the pure tetragonal 3Y-TZP.

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Mechanical and microstructural properties of ultra-translucent dental zirconia ceramic stabilized with 5 mol% yttria

Cited by 28 publications

References 33 publications

Comparison of surface topography and roughness in different yttrium oxide compositions of dental zirconia after grinding and polishing

Comparison of surface topography and roughness in different yttrium oxide compositions of dental zirconia after grinding and polishing

Effect of sintering regimes and thickness on optical properties of zirconia ceramics for dental applications

Gelcast Zirconia Ceramics With High Strength and Simultaneously High Translucency for Dental Applications

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