The Effect of Dental Grinding and Sandblasting on the Biaxial Flexural Strength and Weibull Modulus of Tetragonal Zirconia

2003 ◽  
Vol 254-256 ◽  
pp. 683-686 ◽  
Author(s):  
Tomaž Kosmač
Keyword(s):  
Flexural Strength ◽  
Weibull Modulus ◽  
Tetragonal Zirconia ◽  
Biaxial Flexural Strength

Effect of Thermocycling on Biaxial Flexural Strength of CAD/CAM, Bulk Fill, and Conventional Resin Composite Materials

2019 ◽  
Vol 44 (5) ◽  
pp. E254-E262 ◽  
Author(s):  
EB Benalcázar Jalkh ◽  
CM Machado ◽  
M Gianinni ◽  
I Beltramini ◽  
MMT Piza ◽  
...  
Keyword(s):  
Composite Materials ◽  
Flexural Strength ◽  
Weibull Modulus ◽  
Resin Composite ◽  
Oral Care ◽  
Testing Machine ◽  
Biaxial Flexural Strength ◽  
Computer Aided ◽  
Cad Cam ◽  
Characteristic Stress

SUMMARY New resin-based restorative materials have been developed, such as computer-aided design/computer-aided manufacturing (CAD/CAM) and bulk-fill composites, as an alternative to traditional layering techniques. This study evaluated the biaxial flexural strength (BFS) before and after thermocycling of five different resin composites: one hybrid resin/ceramic CAD/CAM indirect material, Lava Ultimate CAD-CAM Restorative (LU, 3M Oral Care); a conventional composite, Filtek Z350 XT (Z350, 3M Oral Care); two bulk-fill composites, Tetric N-Ceram Bulk Fill (TBF, Ivoclar Vivadent) and Filtek Bulk Fill (FBF, 3M Oral Care); and one bulk-fill flow resin composite, Filtek Bulk Fill Flow (FBFF, 3M Oral Care). Three hundred disc-shaped specimens (6.5 mm in diameter and 0.5 mm thick) were fabricated and divided into five groups (n=30 for each composite and condition). The BFS test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min immediately (i, 24 hours) and after thermocycling (a, 500 thermal cycles of 5°C to 55°C with a 30-second dwell time). The Weibull modulus (m) and characteristic stress (η) were calculated, and a contour plot was used (m vs η) to detect differences between groups (95% two-sided confidence intervals). Significantly higher characteristic stress was observed for LUi (286.6 MPa) and Z350i (248.8 MPa) compared to the bulk-fill groups (FBFi=187.9 MPa, FBFFi=175.9 MPa, TBFi=149.9 MPa), with no differences between LUi and Z350i. Thermocycling significantly decreased the characteristic stress of all groups with the highest values observed for LUa (186.7 MPa) and Z350a (188.9 MPa) and the lowest for FBFFa (90.3 MPa). Intermediate values were observed for FBFa (151.6 MPa) and TBFa (122.8 MPa). The Weibull modulus decreased only for FBFa compared to FBFi. Composition and thermocycling significantly influenced the biaxial flexural strength of resin composite materials.

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.

scholarly journals Effect of Low-Concentration Hydrofluoric Acid Etching on Shear Bond Strength and Biaxial Flexural Strength after Thermocycling

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1409
Author(s):  
You-Jung Kang ◽  
Yooseok Shin ◽  
Jee-Hwan Kim
Keyword(s):  
Phase Transformation ◽  
Flexural Strength ◽  
Bond Strength ◽  
Hydrofluoric Acid ◽  
Shear Bond Strength ◽  
Tetragonal Zirconia ◽  
Resin Cement ◽  
Air Abrasion ◽  
Biaxial Flexural Strength ◽  
Group A

This study evaluated the shear bond strength (SBS) and biaxial flexural strength (BFS) of resin cements according to the surface treatment method using low-temperature hot etching with hydrofluoric acid (HF) on a yttrium-stabilized tetragonal zirconia (Y-TZP) surface; 96 discs and 72 cubes for BFS and SBS tests for Y-TZP were randomly divided into four groups of BFS and three groups of SBS. Specimens were subjected to the following surface treatments: (1) no treatment (C), (2) air abrasion with 50 μm Al2O3 particles (A), (3) hot etching with HF at 100 °C for 10 min (E), and (4) air abrasion + hot etching (AE). After treatments, the specimens were coated with primer, and resin cement was applied with molds. The specimens were evaluated for roughness (Ra) via scanning electron microscopy and x-ray diffraction, and the data were analyzed by an analysis of variance (ANOVA) and Kruskal–Wallis tests. Group E produced significantly higher SBS compared to group A and AE before and after thermocycling. The BFSs of all groups showed no significant differences before thermocycling; however, after thermocycling, C and E treatment groups were significantly higher compared to group A and AE. All groups showed phase transformation. Group E was observed lower monoclinic phase transformation compared to other groups.

scholarly journals Additively Manufactured Zirconia for Dental Applications

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3694
Author(s):  
Hiroto Nakai ◽  
Masanao Inokoshi ◽  
Kosuke Nozaki ◽  
Keiji Komatsu ◽  
Shingo Kamijo ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Cross Sections ◽  
Oral Care ◽  
Tetragonal Zirconia ◽  
Crystallographic Analysis ◽  
Weibull Analysis ◽  
X Ray Diffraction ◽  
Biaxial Flexural Strength ◽  
Dental Applications ◽  
Similar Phase

We aimed to assess the crystallography, microstructure and flexural strength of zirconia-based ceramics made by stereolithography (SLA). Two additively manufactured 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP: LithaCon 3Y 230, Lithoz; 3D Mix zirconia, 3DCeram Sinto) and one alumina-toughened zirconia (ATZ: 3D Mix ATZ, 3DCeram Sinto) were compared to subtractively manufactured 3Y-TZP (control: LAVA Plus, 3M Oral Care). Crystallographic analysis was conducted by X-ray diffraction. Top surfaces and cross-sections of the subsurface microstructure were characterized using scanning electron microscopy (SEM). Biaxial flexural strength was statistically compared using Weibull analysis. The additively and subtractively manufactured zirconia grades revealed a similar phase composition. The residual porosity of the SLA 3Y-TZPs and ATZ was comparable to that of subtractively manufactured 3Y-TZP. Weibull analysis revealed that the additively manufactured LithaCon 3Y 230 (Lithoz) had a significantly lower biaxial flexural strength than 3D Mix ATZ (3D Ceram Sinto). The biaxial flexural strength of the subtractively manufactured LAVA Plus (3M Oral Care) was in between those of the additively manufactured 3Y-TZPs, with the additively manufactured ATZ significantly outperforming the subtractively manufactured 3Y-TZP. Additively manufactured 3Y-TZP showed comparable crystallography, microstructure and flexural strength as the subtractively manufactured zirconia, thus potentially being a good option for dental implants.

Mechanical Behavior of Ceramic Monolithic Systems With Different Thicknesses

2019 ◽  
Vol 44 (5) ◽  
pp. E244-E253
Author(s):  
D Longhini ◽  
COM Rocha ◽  
LT de Oliveira ◽  
NG Olenscki ◽  
EA Bonfante ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Mechanical Behavior ◽  
Weibull Modulus ◽  
Mechanical Characterization ◽  
Fracture Load ◽  
Stabilized Zirconia ◽  
Weibull Statistics ◽  
Static Test ◽  
Biaxial Flexural Strength ◽  
Post Hoc

SUMMARY Objectives: This study assessed the fully stabilized zirconia (FSZ) Prettau Anterior, the partially stabilized zirconia (PSZ) Prettau, and the lithium disilicate IPS e.max CAD (LD) through microstructural and mechanical characterization and effect of thickness on fracture load of the ceramics. Methods and Materials: Disk-shaped specimens (12 mm diameter and 1.2 mm thickness) were prepared for biaxial flexural strength (BFS) and Weibull statistics (n=30). For the fracture load static test (FLST) and Weibull statistics (n=30), disk-shaped specimens 12 mm in diameter and thicknesses of 0.5 mm, 1 mm, and 1.5 mm were cemented on an epoxy-resin substrate. Results: BFS (MPa) results were PSZ: 683.0 ± 70.23; FSZ: 438.6 ± 64.1; and LD: 248.6 ± 37.3. One-way analysis of variance (ANOVA) for BFS was significant (p<0.001), and the Tukey post hoc test showed differences among all ceramics. There was difference in characteristic strength, but there was no difference in Weibull modulus. Two-way ANOVA for FLST was significant for ceramic (p<0001), thickness (p<0001), and interaction (p<0001). There was no difference among all ceramics at the 0.5 mm thickness. PSZ had higher values for the 1.0 mm and 1.5 mm thicknesses. LD of 1.5 mm thickness exhibited a higher FLST than FSZ. Conclusions: PSZ had the highest BFS, but when cemented on a substrate, all ceramics with 0.5 mm thickness behaved similarly. Despite the lower BFS, LD had a fracture load similar or superior to FSZ when cemented on a substrate.

Development of Y-TZP Pre-Sintered Blocks for CAD-CAM Machining of Dental Prostheses

2008 ◽  
Vol 591-593 ◽  
pp. 712-716 ◽  
Author(s):  
Roberta M.C. Sasahara ◽  
H.N. Yoshimura ◽  
Cátia Fredericci ◽  
Alberto Calasans ◽  
Paulo Francisco Cesar ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Vickers Hardness ◽  
Empirical Equation ◽  
Tetragonal Zirconia ◽  
Linear Shrinkage ◽  
Dental Prostheses ◽  
Biaxial Flexural Strength ◽  
Cad Cam ◽  
Dental Applications ◽  
Tetragonal Zirconia Polycrystal

The aim of this work was to establish a route to produce pre-sintered blocks of Y-TZP (yttria stabilized tetragonal zirconia polycrystal) suitable to be machined in a commercial CADCAM system, used to manufacture crowns and bridge frameworks for dental applications. Two commercial Y-TZP powders were investigated. The powders were pressed with different compaction pressures (40 to 500 MPa) and pre-sintered at temperature ranging from 900 to 1100°C. Vickers hardness, biaxial flexural strength, and linear shrinkage could be correlated to the relative density of pre-sintered samples. Using an empirical equation, pre-sintered blocks with a pre-defined density could be prepared. The blocks withstood the machining in a CAD-CAM system, and the machined and sintered crowns presented good adaptation.

Effects of Pretreatment, Specimen Thickness, and Artificial Aging on Biaxial Flexural Strength of Two Types of Y-TZP Ceramics

2019 ◽  
Vol 44 (6) ◽  
pp. 615-624
Author(s):  
A Sundh ◽  
W Kou ◽  
G Sjögren
Keyword(s):  
Flexural Strength ◽  
Surface Treatment ◽  
Pearson Correlation ◽  
Tetragonal Zirconia ◽  
Specimen Thickness ◽  
Test Analysis ◽  
Heat Treated ◽  
Biaxial Flexural Strength ◽  
Correlation Tests ◽  
Post Hoc

SUMMARYObjectives:To evaluate the effects of surface treatment, specimen thickness, and aging on the biaxial flexural strength (BFS) of two types of yttria-stabilized, tetragonal zirconia polycrystal (Y-TZP) ceramics.Methods and Materials:Disc-shaped specimens, 0.4 and 1.3 mm thick, made from hot isostatic pressed (Denzir) and non–hot isostatic pressed (ZirPlus) Y-TZP, were sandblasted, heat treated, and autoclaved. The surface topography was assessed in accordance with European Standard 623-624:2004 and the BFS tests in accordance with International Organization for Standardization Standard 6872:2008. For statistical analyses, one-way Shapiro-Wilk test, analysis of variance (post hoc: least significant differences), Mann-Whitney U-test, and Pearson correlation tests (p<0.05) were used.Results:As delivered, the BFS of the 0.4-mm ZirPlus was >1.3-mm ZirPlus (p<0.01), and the BFS of the 0.4-mm Denzir was >1.3-mm Denzir (p<0.001). Sandblasting with 0.2 MPa reduced the BFS of the ZirPlus and Denzir discs (p<0.01), whereas sandblasting with 0.6 MPa increased the BFS of the 0.4-mm Denzir (p<0.001) and reduced the BFS of the 0.4-mm ZirPlus (p<0.05). Heat treatment significantly reduced the BFS of all the groups except for the 0.6 MPa sandblasted 0.4-mm ZirPlus. Autoclaving reduced the BFS of the as-delivered ZirPlus and Denzir specimens (p<0.001), whereas autoclaving the 0.6 MPa sandblasted and heat-treated specimens had no effect (p>0.05) on the BFS. The 0.6 MPa sandblasted, heat-treated, and autoclaved 0.4-mm Denzir exhibited higher BFS than the 0.6 MPa sandblasted, heat-treated, and autoclaved 0.4-mm ZirPlus (p<0.05).Conclusions:Thickness and surface treatment of Y-TZP–based ceramics should be considered since those factors could influence the BFS of the material.

scholarly journals Effect of Different Surface Treatments on Biaxial Flexural Strength of Yttria-stabilized Tetragonal Zirconia Polycrystal

2018 ◽  
Vol 19 (3) ◽  
pp. 318-323
Author(s):  
Teerthesh Jain ◽  
Amit Porwal ◽  
Sumanth Babu ◽  
Zahid A Khan ◽  
Chandeep Kaur ◽  
...  
Keyword(s):  
Low Temperature ◽  
Flexural Strength ◽  
Tetragonal Zirconia ◽  
Surface Treatments ◽  
Control Group ◽  
Significant Difference ◽  
Biaxial Flexural Strength ◽  
Computer Aided ◽  
The Impact ◽  
Tetragonal Zirconia Polycrystal

ABSTRACT Introduction Ceramics are widely applied in dentistry owing to their excellent mechanical and physical attributes. The most popular ceramics are Lava™, KaVo Everest, and Cercon. However, it is unclear whether or not a different surface treatment along with low-temperature aging and mechanical loading (ML) affects the physical properties of computer-aided design (CAD)/computer-aided manufacturing (CAM)-machined yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic. Aim The objective of this research was to assess the impact of various surface treatments as air-particle abrasion, ML, low-temperature degradation (LTD), and their cumulative effects on biaxial flexural properties of Y-TZP. Materials and methods Totally, 50 specimens were fabricated by CAD–CAM machining from Cercon® and divided into five groups following different surface treatments as control (C), air-particle abrasion (Si), ML, LTD, and cumulative treatment (CT) group. Results were investigated by two-way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) test. Results The highest biaxial flexural strength was observed in the Si group (950.2 ± 126.7 MPa), followed by the LTD group (861.3 ± 166.8 MPa), CT group (851.2 ± 126.5 MPa), and the least with ML (820 ± 110 MPa). A significant difference was observed in the two-way ANOVA test. X-ray diffraction (XRD) analysis showed that the control group consists of 100% tetragonal zirconia and the maximum amount of monoclinic phase was obtained after LTD. Conclusion No negative effect on biaxial flexural strength was observed; indeed, it increases the biaxial strength. Hence, these surface treatments can be done in routine clinical practice to improve the performance of ceramic restoration. How to cite this article Jain T, Porwal A, Babu S, Khan ZA, Kaur C, Jain RB. Effect of Different Surface Treatments on Biaxial Flexural Strength of Yttria-stabilized Tetragonal Zirconia Polycrystal. J Contemp Dent Pract 2018;19(3):318-323.

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