Evaluation of Biaxial Flexural Strength and Translucency of Multichromatic Translucent Zirconia and Lithium Disilicate Ceramics (original) (raw)
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Journal of dentistry, 2017
To compare three different compositions of Yttria-Tetragonal Zirconia Polycrystal (Y-TZP) ceramic and a lithium disilicate ceramic in terms of flexural strength and translucency. Three zirconia materials of different composition and translucency, Aadva ST [ST], Aadva EI [EI] and Aadva NT [NT](GC Tech, Leuven, Belgium) were cut with a slow speed diamond saw into beams and tabs in order to obtain, after sintering, dimensions of 1.2×4.0×15.0mm and 15.0×15.0×1.0mm respectively. Blocks of IPS e.max CAD LT were cut and crystallized in the same shapes and dimensions and used as a reference group [LD]. Beams (n=15) were tested in a universal testing machine for three-point bending strength. Critical fracture load was recorded in N, flexural strength (σ in MPa), Weibull modulus (m) and Weibull characteristic strength (σ(0) in MPa) were then calculated. Tabs (n=10) were measured with a spectrophotometer equipped with an integrating sphere. Contrast Ratios were calculated as CR=Yb/Yw. SEM of t...
Translucency and flexural strength of monolithic translucent zirconia and porcelain-layered zirconia
Dental materials journal, 2015
This study aims to investigate the effectiveness of monolithic translucent TZP with different colors and porcelain-layered TZP by evaluating their colors and strengths. Different mixing ratios of Zpex to Zpex-Yellow as translucent TZP, conventional opaque TZP (TZ-3YB-E) (Tosoh, Tokyo) as a control, and veneering porcelain (CERABIEN ZR, body porcelain, Noritake, Tokyo) with shade A3 as a typical shade. Disk-shaped specimens of 13 mm diameter and 1.5 mm thickness were prepared. These specimens were observed under reflected and transmitted light, and the translucency parameter (TP) values were measured. Strength was also evaluated with flexural strength in a biaxial bending test. The TP values of the monolithic TZP, Zpex100>Zpex70>Zpex50>TZ3YB, were larger in this order. The flexural strength of all the monolithic TZP showed approximately 1,000 MPa. It is suggested that colored translucent TZP is clinically useful when used as monolithic restorations.
Effect of different sintering process on flexural strength of translucency monolithic zirconia
Journal of Clinical and Experimental Dentistry, 2018
Background: Sintering process is responsible for the strength of zirconia restoration. This study evaluated the effect of different sintering temperatures and sintered-holding times on flexural strength of translucency monolithic zirconia. Material and Methods: One hundred and thirty five zirconia bar specimens (width-length-thickness = 10×20×1.5 mm) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic and randomly divided into nine groups to be sintered at different temperatures [decreasing-(S D , 1350°C), regular-(S R , 1450°C), and increasing-(S I , 1550°C) sintering temperature] and different sintered-holding times [shortening-(H S , 60 min), regular-(H R , 120 min), and prolonged-(H P , 180 min) sintered-holding time]. Flexural strength was determined using three-point bending test in a universal testing machine at 1 mm/min crosshead speed. An analysis of variance (ANOVA) and Tukey's multiple comparisons were used to determine for statistically significant difference of flexural strength (α=0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σ o) of the flexural strength. The crystal sizes were microscopically examined using scanning electron microscope (SEM). The phase composition of zirconia was determined using X-ray diffraction (XRD).
Comparative Evaluation of the Translucency of Monolithic Zirconia
The Journal of Contemporary Dental Practice
Aims and objectives: New techniques are being developed to invent zirconia with high translucency and better esthetics leading to the development of several brands of monolithic zirconia. The aim of this study is to compare the translucency of three brands of zirconia available for the fabrication of monolithic restorations. Materials and methods: An in vitro study was designed to compare the translucency of three brands of zirconia available for the fabrication of monolithic restorations: Zirlux Zirconia (Vivadent Ivoclar), Zenostar Zr Translucent Zirconia (Weiland), and BruxZir Zirconia (Glidewell). All specimens were prepared to 0.5 mm thickness. Thirty zirconia specimens from each material were finished and polished. After drying, specimens were fired according to the manufacturers' recommendations. A spectrophotometer (Color i5) was used for the translucency test. Each specimen was presented at the view port permitting the light to hit the center of the specimen. Results were saved into the software until all measurements were completed. The data were then transferred to an Excel sheet where translucency parameters were calculated. The one-way analysis of variance (ANOVA) test and the post hoc Bonferroni test were performed to analyze the results. Results: The one-way ANOVA test revealed that there was a statistically significant difference between the groups. This study showed lower translucency of BruxZir in comparison to Zenostar and Zirlux when tested under standardized conditions. Conclusion: There is a statistically significant difference in the translucency between the different brands of zirconia available for monolithic restoration fabrication. Clinical significance: Different brands of zirconia have different degrees of translucency. Material selection should be customized in each case.
Translucency and Biaxial Flexural Strength of Monolithic Zirconia as Affected by Sintering Speeds
Egyptian Dental Journal
Statement of the problem: Approaches towards reducing fixed prosthetic restoration fabrication times include; (CAD/CAM) chair side systems in addition to rapid sintering cycles, which can be carried out in minutes rather than hours in order to deliver zirconia-based restorations in one visit .However, limited information is available regarding the effect of rapid sintering on properties of monolithic translucent zirconia. Aim of the study: The aim of this study was to evaluate the effect of changing the sintering speed (classic, speed and super speed cycles) on translucency and biaxial flexural strength of monolithic translucent zirconia before and after thermodynamic aging. Materials & Methods: 36 monolithic translucent zirconia discs (10mm diameter×0.8mm thickness) were CAD/CAM fabricated from translucent zirconia blocks(In Coris TZI) and randomly divided into three main groups (n=12 each) according to the sintering speed; group I: samples sintered by classic sintering cycle (sintering at 1510°C for 120 min holding time & 8 hours total cycle time), group II: speed sintering (sintering at 1540°C for 25 min holding time & 2 hours total cycle time) and group III: super speed sintering (sintering at 1580°C for 10 min holding time representing the total firing cycle). In each group, half of the samples were evaluated in the non-aged condition (subgroup1, n=6) while the other half were evaluated after thermodynamic aging (subgroup2, n=6) in a chewing simulator. Translucency parameter (TP) and contrast ratio (CR) were measured using a digital reflective spectrophotometer. Biaxial flexural strength (MPa) was tested using piston on three ball technique in a universal testing machine. Representative sample from each subgroup was analyzed by Scanning electron microscope. Statistical analysis was performed using Two-way ANOVA and Tukey's post-hoc tests (P ≤ 0.05). Results: Two-way ANOVA revealed that sintering speed and thermodynamic aging had a statistically significant effect on mean (TP), (CR).Either before or after aging, classic cycle showed the statistically significantly highest mean (TP) & lowest (CR) values. On the other hand, biaxial flexural strength was statistically significantly affected by the sintering speed only and not by thermodynamic aging; the super speed cycle registered the lowest mean biaxial flexural strength before and after thermodynamic aging.
Influence of aging on flexural strength of translucent zirconia for monolithic restorations
Journal of Prosthetic Dentistry, 2017
In addition to its mechanical and physical properties, which are superior to other ceramic materials, 1,2 yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) is tooth colored and is considered biocompatible in terms of soft tissue response, which may facilitate soft tissue health and esthetics. 3-6 Consequently, for the past decade, Y-TZP has been used as a restorative material for multiple dental applications including crown copings, fixed dental prosthesis (FDP) frameworks, implant abutments, and screw-retained implant frameworks. 1,7,8 The first generation of Y-TZP was considered opaque 9 and therefore indicated for crown copings and FDP frameworks in both the anterior and the posterior segments, layered with veneering
The Journal of prosthetic dentistry, 2016
Studies comparing the translucency of zirconias and lithium disilicates are limited. The purpose of this in vitro study was to measure the translucency of recently developed translucent zirconias and compare them with lithium disilicate. Five types of zirconia, Prettau Anterior (Zirkonzahn GmbH), BruxZir (Glidewell Laboratories), Katana HT, Katana ST, and Katana UT (Kurary Noritake Dental Inc), and 1 type of lithium disilicate, e.max CAD LT (Ivoclar Vivadent AG), were assessed. Non-colored zirconia test specimens (n=5) were prepared as rectangles with dimensions of 15×10×0.5 and 15×10×1.0 mm. The shade of lithium disilicate was B1. A spectrophotometer (Evolution 300 UV-Vis) with an integrating sphere was used to evaluate the total transmittance of light as a percentage (Tt%) at a wavelength of 555 nm for comparison among groups. The Welch robust test for equality of means was used to compare group means (α=.025) and post hoc pairwise comparisons among groups were performed with the ...
Effect of Glazing on Flexural Strength of Full-Contour Zirconia
International Journal of Dentistry, 2018
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 diffe...
The use of monolithic [yttria (Y2O3)-stabilized tetragonal zirconia (ZrO2) polycrystalline] (Y-TZP) ceramics to restore teeth is expanding in dentistry. However, there are still some problems about color matching and the translucency of these ceramics. The employment of Y-TZP ceramics in aesthetically critical regions is questionable due to the insufficient translucency and opacity of the restorations. The objective of this review was to assess the factors affecting the translucency of monolithic Y-TZP ceramics for a better understanding the relevant parameters in restorations. The translucency of polycrystalline ceramics is a complex phenomenon. Apprehending the translucency regarding ceramics requires their knowledge of physical, chemical and microstructural characteristics with the light interactions among them.
Biaxial Flexural Strength of Different Monolithic Zirconia upon Post-Sintering Processes
European Journal of Dentistry
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 ...