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 surface roughness, phase transformation, and biaxial flexural strength of dental zirconia

2021 ◽  
Vol 15 (3) ◽  
pp. 210-218
Author(s):  
Niknaz Yahyazadehfar ◽  
Maryam Azimi Zavaree ◽  
Sayed Shojaedin Shayegh ◽  
Mobin Yahyazadehfar ◽  
Tabassom Hooshmand ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Phase Transformation ◽  
Flexural Strength ◽  
Surface Treatment ◽  
Monoclinic Phase ◽  
Pearson Correlation ◽  
Surface Treatments ◽  
Post Hoc ◽  
And Control

Background. Interfacial failures at the cement‒restoration interface highlights the importance of effective surface treatment with no adverse effect on the zirconia’s mechanical properties. This study aimed to determine the effect of different surface treatments on dental graded zirconia’s surface roughness and certain mechanical properties. Methods. Forty sintered zirconia specimens were randomly divided into four groups (n=10): control (no surface treatment), sandblasting (SA), grinding with diamond bur (GB), and Er,Cr:YSGG laser (LS). Following surface treatment, the surface roughness and surface topography of the specimens were examined. X-ray diffraction (XRD) was conducted. In addition, the biaxial flexural strengths of specimens were evaluated. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey tests; the Pearson correlation coefficient was calculated between either volumetric percentage of monoclinic phase or roughness and flexural strength of specimens (α=0.05). Results. The GB group exhibited significantly greater surface roughness compared to the other groups (P<0.005). The LS and control groups exhibited a significantly lower volumetric percentage of the monoclinic phase (P<0.001) than the GB and SA treatments. The SA group exhibited significantly higher flexural strength than the control (P=0.02) and GB groups (P<0.01). Furthermore, the Weibull analysis for the LS showed higher reliability for the flexural strength than other treatments. Conclusion. Er,Cr:YSGG laser treatment, with the lowest extent of phase transformation and reliable flexural strength, can be a promising choice for surface treatment of zirconia.

scholarly journals Biaxial Flexural Strength of Different Monolithic Zirconia upon Post-Sintering Processes

2022 ◽  
Author(s):  
Niwut Juntavee ◽  
Apa Juntavee ◽  
Thipradi Phattharasophachai
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Biaxial Flexural Strength ◽  
Monolithic Zirconia ◽  
Treatment Procedures ◽  
Post Hoc ◽  
Sintering Processes

Abstract Objective Different post-sintering processes are expected to be a reason for alteration in the strength of zirconia. This study evaluated the effect of post-sintering processes on the flexural strength of different types of monolithic zirconia. Materials and Methods A total of 120 classical- (Cz) and high-translucent (Hz) monolithic zirconia discs (1.2 mm thickness and 14 mm in Ø) were prepared, sintered, and randomly divided into four groups to be surface-treated with (1) as-glazed (AG); (2) finished and polished (FP); (3) finished, polished, and overglazed (FPOG); and (4) finished, polished, and heat-treated (FPHT) technique (n = 15). Biaxial flexural strength (σ) was determined on a piston-on-three ball in a universal testing machine at a speed of 0.5 mm/min. Statistical Analysis Analysis of variance, and post hoc Bonferroni multiple comparisons were determined for significant differences (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristic strength (σ0). The microstructures were examined with a scanning electron microscope and X-ray diffraction. Results The mean ± standard deviation value of σ (MPa), m, and σ0 were 1,626.43 ± 184.38, 9.51, and 1,709.79 for CzAG; 1,734.98 ± 136.15, 12.83, and 1,799.17 for CzFP; 1,636.92 ± 130.11, 14.66, and 1,697.63 for CzFPOG; and 1,590.78 ± 161.74, 10.13, and 1,663.82 for CzFPHT; 643.30 ± 118.59, 5.59, and 695.55 for HzAG; 671.52 ± 96.77, 3.28, and 782.61 for HzFP; 556.33 ± 122.85, 4.76, and 607.01 for HzFPOG; and 598.36 ± 57.96, 11.22, and 624.89 for HzFPHT. The σ was significantly affected by the post-sintering process and type of zirconia (p < 0.05), but not by their interactions (p > 0.05). The Cz indicated a significantly higher σ than Hz. The FP process significantly enhanced σ more than other treatment procedures. Conclusion Post-sintering processes enabled an alteration in σ of zirconia. FP enhanced σ, while FPOG and FPHT resulted in a reduction of σ. Glazing tends to induce defects at the glazing interface, while heat treatment induces a phase change to tetragonal, both resulted in reducing σ. Finishing and polishing for both Cz and Hz monolithic zirconia is recommended, while overglazed or heat-treated is not suggested.

scholarly journals Biaxial flexural strength of different types of monolithic zirconia

2019 ◽  
Vol 22 (1) ◽  
pp. Process
Author(s):  
Shereen Ahmed Nossair ◽  
Tarek Salah ◽  
Kamal Khaled Ebeid
Keyword(s):  
Flexural Strength ◽  
Zirconia Ceramic ◽  
Group 4 ◽  
Dental Esthetics ◽  
Biaxial Flexural Strength ◽  
Different Types ◽  
Monolithic Zirconia ◽  
Group 5 ◽  
Group 2 ◽  
Post Hoc

Objective: This study was designed to evaluate the biaxial flexural strength (BFS) of different types of unshaded and shaded monolithic zirconia. Material and Methods: 120 monolithic zirconia ceramic discs were fabricated. They were divided into twelve groups (n=10), Group 1; Bruxzir unshaded, Group 2; Bruxzir shaded A2, Group 3; Bruxzir anterior white, Group 4; Bruxzir anterior shade A2, Group 5; Prettau unshaded, Group 6; Prettau shaded with A2 coloring liquid, Group 7; Prettau anterior white, Group 8; Prettau anterior shaded with A2 coloring liquid, Group 9; Katana HT white, Group 10; Katana HT shade A2, Group 11; Katana ST white, Group 12; Katana ST shade A2. All discs were milled using a dental milling machine, and had final dimensions after sintering of 15 mm diameter and 1 mm thickness. BFS was tested using piston on three ball technique. Results:  One-way ANOVA revealed significant differences among the 12 groups. Tukey post-hoc tests revealed no significant differences between the groups 3, 4, ,7 ,8 11, and 12. However, they all had BFS values that are significantly lower than all other groups. Group 2 showed statistically significant higher BFS values when compared to group 3,4, 7, 8, 11, and 12 while it showed statistically significant lower values when compared to groups 1, 5, 6, 9, and 10. Conclusion: Increase in the yttria content in zirconia led to a decrease in its BFS. Shading of zirconia did not have a significant effect on the final strength of zirconia. KeywordsDental ceramics; Dental esthetics; Flexural strength; Shaded zirconia. 

Effect of surface treatment on biaxial-flexural strength of lithium disilicate

2015 ◽  
Vol 31 ◽  
pp. e53-e54
Author(s):  
S. Singhal ◽  
T. Hill ◽  
O. Nihlawi ◽  
S.A. Antonson ◽  
G. Tysowsky
Keyword(s):  
Flexural Strength ◽  
Surface Treatment ◽  
Lithium Disilicate ◽  
Biaxial Flexural Strength ◽  
Effect Of Surface

scholarly journals Post-gel shrinkage, elastic modulus, and stress generated by orthodontic adhesives

2019 ◽  
Vol 90 (2) ◽  
pp. 278-284
Author(s):  
Michael J. Rasmussen ◽  
Cameron Togrye ◽  
Terry M. Trojan ◽  
Daranee Tantbirojn ◽  
Antheunis Versluis
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Color Change ◽  
Bending Test ◽  
Shrinkage Stress ◽  
Element Analysis ◽  
Cross Sectional ◽  
Test Analysis ◽  
Orthodontic Adhesives ◽  
Post Hoc

ABSTRACT Objectives: To measure post-gel shrinkage, elastic modulus, and flexural strength of orthodontic adhesives and to predict shrinkage stress using finite element analysis (FEA). Materials and Methods: The following 6 orthodontic adhesives were tested: Transbond XT (3M Unitek, Monrovia, Calif), Transbond Plus Color Change (3M Unitek), Greengloo (Ormco, Brea, Calif), Ortho Connect (GC America, Alsip, Ill), Trulock (RMO, Denver, Colo), GoTo (Reliance, Itasca, Ill). Post-gel shrinkage was measured using a biaxial strain gauge during light curing. Elastic modulus and flexural strength were measured with a 4-point bending test. Analysis of variance and Student-Newman-Keuls post hoc tests were used to compare the shrinkage, elastic modulus, and flexural strengths among the materials (α = .05). Shrinkage stresses caused by the post-gel shrinkage and elastic modulus values were calculated using a cross-sectional FEA of a metallic bracket bonded to an incisor. Results: Properties were highly different among the adhesives (P ≤ .0001). Transbond XT (0.38 ± 0.09 percent volumetric contraction) and GoTo (0.42 ± 0.05 percent volumetric contraction) had the lowest post-gel shrinkage; Transbond Plus Color Change had the highest (0.84 ± 0.08 percent volumetric contraction). OrthoConnect (6.8 ± 0.6 gigapascals) had the lowest elastic modulus; GoTo (28.3 ± 3.1 gigapascals) had the highest. Trulock (64.1 ± 8.2 megapascals) had the lowest flexural strength; Greengloo (139.1 ± 20.7 megapascals) had the highest. FEA showed that the highest shrinkage stresses were generated with Transbond Plus Color Change and the lowest with OrthoConnect. Conclusions: Post-gel shrinkage of orthodontic adhesives was comparable with restorative composites, which are known to create shrinkage stresses in restored teeth. FEA indicated that this shrinkage creates stresses in the adhesive and in the enamel around the brackets.

scholarly journals Effect of Glazing on Flexural Strength of Full-Contour Zirconia

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Hattanas Kumchai ◽  
Patrapan Juntavee ◽  
Arthur F. Sun ◽  
Dan Nathanson
Keyword(s):  
Flexural Strength ◽  
Significant Influence ◽  
Testing Machine ◽  
Surface Treatments ◽  
Bending Test ◽  
Three Point Bending ◽  
Universal Testing ◽  
Heat Treated ◽  
Significant Difference ◽  
Post Hoc

Objective. The purpose of this study was to evaluate the effect of glazing on flexural strength of highly translucent zirconia materials. Materials and Methods. Specimens of three brands of zirconia bars (Prettau Zirconia, Zirkonzahn; inCoris TZI, Sirona; and Zirlux FC, Pentron Ceramics) were prepared and polished according to manufacturers’ instructions. Final specimen dimensions were 20 × 4 × 2 mm. The specimens from each brand were divided into 3 groups (N = 10): control, heat-treated, and glazed. Heat-treated specimens were fired without the application of the glaze material. The glaze material was applied to the glazed specimens before being fired. A three-point bending test (15 mm span) was performed in an Instron universal testing machine (ISO 6872). Data were analyzed by ANOVA and Tukey’s HSD post hoc test (α = 0.05). Results. Two-way ANOVA showed a significant influence of surface treatments on flexural strength of zirconia materials (P≤0.05). There was no significant difference in flexural strength among the different brands of highly translucent zirconia (P≥0.05). Tukey’s HSD post hoc test showed that specimens in the “glazed” group had significantly lower flexural strength than the control and heat-treated groups (P≤0.05). Conclusion. Within the limitations of the study, external glazing decreased the flexural strength of highly translucent zirconia.

scholarly journals Surface Topography, Gloss and Flexural Strength of Pressable Ceramic After Finishing-Polishing Protocols

2019 ◽  
Vol 30 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Fernanda P. Silva ◽  
Ana L. R. Vilela ◽  
Matheus M. G. Almeida ◽  
André R. F. Oliveira ◽  
Luís H. A. Raposo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Lower Surface ◽  
Good Alternative ◽  
Sem Analysis ◽  
Force Microscopy ◽  
Biaxial Flexural Strength ◽  
Surface Irregularities ◽  
Post Hoc

Abstract This study evaluated the effect of different finishing-polishing protocols on surface roughness, gloss, morphology and biaxial flexural strength of pressable fluorapatite glass ceramic. Thirty ceramic discs (12x1 mm) were produced and divided into five groups (n=6): CT: control (glaze); DA: fine grit diamond bur; DG: DA + new glaze layer; DP: DA + felt disk with fine grit diamond paste; DK: DA+ sequential polishing with silicon abrasive instruments, goat hair brush and cotton wheel. The specimens were analyzed for surface roughness (Ra) under profilometry and atomic force microscopy (AFM). Gloss was measured with spectrophotometry and micromorphology with scanning electron microscopy (SEM). Flexural strength was assessed by biaxial flexural strength test. Data were analyzed using one-way ANOVA and Tukey’s post hoc test (a=0.05). DK showed the lowest surface roughness values and DA presented the highest in the perfilometer analysis. No significant differences were observed in the AFM for the CT, DG and DK groups, which presented the lower surface roughness; DA and DP had the higher Ra values. The DA, DP and CT showed the lowest surface gloss values, and the reflectance was significantly different from those observed for DK and DG groups. SEM analysis revealed the smoothest surface for DK group, followed by DG and CT groups; DA and DP groups exhibited variable degrees of surface irregularities. No significant differences were observed among groups for the biaxial flexural strength. The polishing protocol used in DK group can be a good alternative for chairside finishing of adjusted pressable fluorapatite glass ceramic surfaces.

Sign in / Sign up

Export Citation Format

Share Document