scholarly journals Effect of Cooling Rate during Glazing on the Mechanical and Optical Properties of Monolithic Zirconia with 3 mol% Yttria Content

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7474
Author(s):  
Mi-Hyang Cho ◽  
Hyo-Joung Seol
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Optical Properties ◽  
Flexural Strength ◽  
Cooling Rate ◽  
Weibull Modulus ◽  
Tetragonal Zirconia ◽  
General Cooling ◽  
Monolithic Zirconia ◽  
Tetragonal Zirconia Polycrystal

Glazing is the final heat treatment process in the manufacturing of a monolithic zirconia prosthesis. Herein, the effect of cooling rate during zirconia glazing was investigated. A 3 mol% yttria-stabilized tetragonal zirconia polycrystal was glazed at the general cooling rate suggested by the manufacturer, as well as at higher and lower cooling rates, and the differences in flexural strength, hardness, optical properties, and crystal structure were evaluated. A higher cooling rate did not affect the flexural strength, hardness, grain size, optical properties, or crystal structure; however, the Weibull modulus decreased by 1.3. A lower cooling rate did not affect the flexural strength, optical properties, or crystal structure; however, the Weibull characteristic strength increased by 26.7 MPa and the Weibull modulus increased by 0.9. The decrease in hardness and the increase in grain size were statistically significant; however, the numerical differences were negligible. This study revealed that a lower cooling rate provides more reliable flexural strength. Therefore, glazing can proceed at a general cooling rate, which takes 3–4 min; however, glazing at a lower cooling rate will provide a more consistent flexural strength if desired, despite being time-consuming.

Mechanical and Surface Properties of Monolithic Zirconia

2018 ◽  
Vol 43 (3) ◽  
pp. E119-E128 ◽  
Author(s):  
LM Candido ◽  
LN Miotto ◽  
LMG Fais ◽  
PF Cesar ◽  
LAP Pinelli
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Weibull Modulus ◽  
Testing Machine ◽  
Fracture Pattern ◽  
Honestly Significant Difference ◽  
Significant Difference ◽  
Tukey Honestly Significant Difference ◽  
Monolithic Zirconia ◽  
Standard Deviations

SUMMARY Purpose: This study compared monolithic zirconia with conventional ones based on mean roughness (Ra), Vickers hardness (VHN), topography, transmittance, grain size, flexural strength (FS), Weibull modulus, and fractographic behavior. Methods and Materials: One monolithic (Prettau Zircon [PR group]) and two conventional (ICE Zirkon Transluzent [IZ group] and BloomZir [BL group]) zirconias were used. Specimens were tested using a profilometer, a microhardness tester, a scanning electron microscope, a spectrophotometer, and a Universal Testing Machine (EMIC DL 2000). Ra, VHN, grain size, and transmittance were analyzed using the Kruskal-Wallis test associated with Dunn test (α=0.05). FS was analyzed using one-way analysis of variance with the Tukey honestly significant difference test (α=0.05). Results: Means and standard deviations of roughness, after sintering (Ra, in μm) and VHN, were, respectively, 0.11 ± 0.01, 1452.16 ± 79.49, for the PR group; 0.12 ± 0.02, 1466.72 ± 91.76, for the IZ group; and 0.21 ± 0.08, 1516.06 ± 104.02, for the BL group. BL was statistically rougher (p<0.01) than PR and IZ. Hardness was statistically similar (p=0.30) for all groups. Means and standard deviations of FS (in MPa) were 846.65 ± 81.97 for the PR group, 808.88 ± 117.99 for the IZ group, and 771.81 ± 114.43 for the BL group, with no statistical difference (p>0.05). Weibull moduli were 12.47 for the PR group, 7.24 for the IZ group, and 6.31 for the BL group, with no statistical differences. The PR and BL groups had higher transmittance values and grain sizes than the IZ group (p<0.05). Although the BL group had some fractures that originated in the center of the tensile surface, fractographic analyses showed the same fracture pattern. Conclusions: All tested zirconia showed similar VHN, and the monolithic zirconia had similar roughness compared to one of the conventional zirconias. In addition, the monolithic zirconia showed similar flexural strength and Weibull modulus compared to the others even though its mean grain size was larger. The total transmittance of monolithic zirconia was higher than only one of the conventional zirconias tested.

scholarly journals Comparison of four monolithic zirconia materials with conventional ones: Contrast ratio, grain size, four-point flexural strength and two-body wear

2016 ◽  
Vol 59 ◽  
pp. 128-138 ◽  
Author(s):  
Bogna Stawarczyk ◽  
Kathrin Frevert ◽  
Andreas Ender ◽  
Malgorzata Roos ◽  
Beatrice Sener ◽  
...  
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Contrast Ratio ◽  
Monolithic Zirconia

Effect of TiN Addition on Microstructure and Mechanical Properties of Zirconia Matrix Ceramic Tool Material

2004 ◽  
Vol 471-472 ◽  
pp. 321-325 ◽  
Author(s):  
Jing Sun ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Sui Lian Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Monoclinic Phase ◽  
Tetragonal Zirconia ◽  
Tool Material ◽  
Strengthening Mechanisms ◽  
Microstructure And Mechanical Properties ◽  
Ceramic Tool Material ◽  
Tetragonal Zirconia Polycrystal

In this paper, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) and TiN/3Y-TZP(adding TiN particles to 3Y-TZP) composites were fabricated by hot-pressing technique. Phase composition, microstructure and mechanical properties of the composites were investigated. It is shown that the flexural strength, fracture toughness and Vickers hardness of TiN/3Y-TZP was significantly improved by the addition of TiN particles compared with 3Y-TZP. The flexural strength of ZYT2 (20wt% TiN addition) is 1318 MPa. The fracture toughness of ZYT4 (40wt% TiN addition) is 16.8MPa·m1/2. The toughening and strengthening mechanisms were analyzed. The XRD results show that the additing of TiN can hinder the transformation from tetragonal phase to monoclinic phase of 3Y-TZP during fabrication process.

Does Diamond Stone Grinding Change the Surface Characteristics and Flexural Strength of Monolithic Zirconia?

2020 ◽  
Vol 45 (3) ◽  
pp. 318-326
Author(s):  
R Aliaga ◽  
LN Miotto ◽  
LM Candido ◽  
LMG Fais ◽  
LAP Pinelli
Keyword(s):  
Flexural Strength ◽  
Surface Morphology ◽  
Weibull Modulus ◽  
Rietveld Method ◽  
Surface Characteristics ◽  
Strength Test ◽  
X Ray ◽  
Dry Grinding ◽  
Monolithic Zirconia ◽  
Scanning Electron

SUMMARY Purpose: The present study evaluated the effect of grinding on the surface morphology, mean roughness, crystalline phase, flexural strength, and Weibull modulus of monolithic (MZ) and conventional (CZ) zirconias. Methods and Materials: CZ and MZ bars and square-shaped specimens were distributed into three subgroups, combining grinding (G) and irrigation (W) with distilled water: Ctrl (Control: no grinding, 20 × 4 × 1.2 mm and 12 × 1.2 mm), DG (dry grinding, 20 × 4 × 1.5 mm and 12 × 1.5 mm), and WG (grinding with irrigation, 20 × 4 × 1.5 mm and 12 × 1.5 mm). The grinding (0.3 mm) was performed on a standardized device using a low-rotation wheel-shaped diamond stone. The four-point flexural strength test was performed on the EMIC 2000 machine (5 KN, 0.5 mm/min). Scanning electron microscopy (SEM) was used to evaluate the surface morphology. An X-ray diffractometer (XRD) was used to obtain the crystalline structures that were analyzed by the Rietveld method. Flexural strength (FS) values were subjected to the Shapiro-Wilk test and two-way analysis of variance followed by the Tukey's test (for all tests, α=0.05). Results: Grinding, either with or without irrigation, did not change the FS of the MZ but increased the FS of the CZ. Both MZ and CZ showed similar morphologic patterns after grinding, and in the WG groups, the grinding was more aggressive. The MZ had greater monoclinic content in all groups; grinding without irrigation caused the smallest t→m transformation. Conclusion: The grinding, when necessary, should be carried out without irrigation for conventional and monolithic zirconias.

Structure and Optical Properties of Al1−xScxN Thin Films

2013 ◽  
Vol 537 ◽  
pp. 140-143 ◽  
Author(s):  
Jing Yang ◽  
Miao Miao Cao ◽  
Yu Dong Li ◽  
Yi Gang Chen
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Band Gap Energy ◽  
Wave Number ◽  
Gap Energy ◽  
Aln Film ◽  
Dc Magnetron Reactive Sputtering ◽  
Xrd Patterns

In this study, c-axis oriented AlN and Al1−xScxN films have been successfully grown on Si (100) and quartz glass by DC magnetron reactive sputtering method. The XRD patterns show that the crystal structure of the Al1−xScxN films is (002) orientation. The grain size and band gap energy (Eg) of the Al1−xScxN films decrease as the Sc concentration increases. The frequency of the E2 (high) mode observed in the Al1−xScxN films shows higher red shift compared to that observed in AlN film and the peak shifts to the low wave number with the increasing of Sc concentration.

scholarly journals Fracture Load and Failure Mode of CAD-on Ceramic Structures

2019 ◽  
Vol 30 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Rodrigo Alessandretti ◽  
Raissa Ribeiro ◽  
Marcia Borba ◽  
Alvaro Della Bona
Keyword(s):  
Failure Mode ◽  
Glass Ceramic ◽  
Tetragonal Zirconia ◽  
Lithium Disilicate ◽  
Fracture Load ◽  
Weibull Statistics ◽  
Monolithic Zirconia ◽  
Trilayer Structure ◽  
Monolithic Structures ◽  
Tetragonal Zirconia Polycrystal

Abstract This study evaluated the fracture load (Lf) and the failure mode of CAD-on (Ivoclar Vivadent) ceramic structures, testing the hypotheses that Lf of multilayer structures is governed by the veneering ceramic strength and that chipping is more frequent in multilayer than monolithic structures. Disc-shaped specimens were fabricated as follows: CAD-on- trilayer structure composed of Y-TZP (yttria stabilized tetragonal zirconia polycrystal- IPS e.max ZirCAD) infrastructure, fusion glass-ceramic (IPS e.max CAD Crystall/Connect) and lithium disilicate-based glass-ceramic (IPS e.max CAD); YLD- bilayer structure composed of Y-TZP infrastructure and fluorapatite layering ceramic (IPS e.max Ceram); LDC- monolithic lithium-disilicate glass-ceramic (IPS e.max CAD); and YZW- monolithic Y-TZP (Zenostar Zr Translucent). The specimens were loaded in compression until failure and fracture surfaces were evaluated using fractographic principles. Lf values were statistically analyzed using the Weibull statistics, Kruskal-Wallis and Dunn tests (a= 0.05). YZW (1329 N) and CAD-on (1085 N) showed the greatest Lf median values, followed by YLD (832 N) and LDC (421 N). All monolithic structures (LDC and YZW) fractured catastrophically and all YLD structures failed by chipping. The CAD-on technique seems to be a very promising fabrication process because it showed high Lf, similar to monolithic zirconia, and small chipping rate.

scholarly journals Effect of Sintering Time on The Marginal and Internal Fit of Monolithic Zirconia Crowns Containing 3-4 Mol% Y2O3

2021 ◽  
Author(s):  
Yunus Emre Ozden ◽  
M.Baris Guncu ◽  
Guliz Aktas ◽  
Senay Canay
Keyword(s):  
Tetragonal Zirconia ◽  
Cubic Phase ◽  
Marginal Gap ◽  
Sintering Time ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Tetragonal Zirconia Polycrystal ◽  
Gap Values

Abstract Background Short-time sintering may offer advantages including saving time and energy but there is limited evidence on the effect that altering sintering time has on the accuracy of monolithic zirconia crowns. The purpose of this in vitro study was to investigate the effect of shortened sintering time on the marginal and internal fit of 3Y-TZP (three mol% yttria-stabilized tetragonal zirconia polycrystal) and 4Y-TZP (four mol% yttria-stabilized tetragonal zirconia polycrystal) monolithic crowns. Methods Sixty monolithic zirconia crowns were fabricated for the maxillary first molar tooth on the prefabricated implant abutment. Groups were created according to the material composition: 3Y-TZP Generation 1 (alumina wt; ≤0.5%, < 15% cubic phase), 3Y-TZP Generation 2 (alumina wt; ≤0.05%, < 15% cubic phase) and 4Y-TZP (alumina wt; ≤0.05%, > 25% cubic phase). Two different sintering protocols were performed: same final sintering temperature (1500°C) and various rates of heating (10°C/min and 40°C/min), cooling down speed (-10°C/min and − 40°C/min), holding time (45 and 120 minutes), and total sintering time (approximately 2 and 7 hours, respectively). The marginal and internal fit of the crowns were determined using the silicone replica technique. Comparisons between groups and sintering times were analyzed using two-way ANOVA. Pairwise multiple comparisons were performed using the t-test (p < 0.05). Results The mean marginal gap values of 4Y-TZP zirconia revealed statistically significant increase for the speed sintering protocol (p < 0.0001), while no difference was observed between the sintering protocols for the mean marginal gap values of 3Y-TZP groups. Conclusions Although all groups showed clinically acceptable gap values (<120 µm), altering the sintering time had an effect on the marginal fit of the crowns manufactured from 4Y-TZP zirconia. Shortening the sintering time may lead to differences within clinically acceptable limits. The manufacturer's recommendations according to material composition should be implemented with care.

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