Effect of in vitro aging on the flexural strength and probability to fracture of Y-TZP zirconia ceramics for all-ceramic restorations

2014 ◽  
Vol 30 (12) ◽  
pp. e306-e316 ◽  
Author(s):  
Eleni Siarampi ◽  
Eleana Kontonasaki ◽  
Konstantinos S. Andrikopoulos ◽  
Nikolaos Kantiranis ◽  
George A. Voyiatzis ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Zirconia Ceramics ◽  
In Vitro Aging ◽  
All Ceramic ◽  
Ceramic Restorations

Effect of In Vitro Ageing on a Cold Isostatic-Pressed Zirconia Ceramic for All Ceramic Restorations

2011 ◽  
Vol 493-494 ◽  
pp. 604-608
Author(s):  
A. Vatali ◽  
E. Siarampi ◽  
Eleana Kontonasaki ◽  
Nikolaos Kantiranis ◽  
T. Zorba ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Tetragonal Zirconia ◽  
Surface Profile ◽  
Zirconia Ceramic ◽  
Full Density ◽  
Zirconia Ceramics ◽  
All Ceramic ◽  
M Phase ◽  
Ceramic Restorations

High strength of Yttria stabilized tetragonal zirconia polycrystal (Y-TZP) zirconia ceramics are sensitive to low temperature degradation (LTD) that leads to exaggerated tetragonal to monoclinic transformation and a surface to depth propagating degradation that diminishes their mechanical properties. In vitro tests for accelerating ageing have been proposed for the prediction of zirconia ceramics clinical performance. The aim of the present work was to investigate the in vitro ageing of a cold isostatic-pressed zirconia ceramic for all ceramic restorations. Bar-shaped specimens milled from a zirconia block (Ivoclar IPS e.max ZirCAD) were sintered to full density, mirror-polished and cut into two equal pieces. One piece was used as control while the other was subsequently aged (steam 134°C / 2 bars / 10 hours). Atomic Force Microscopy (AFM) was used to evaluate the surface profile and the micro-structural features before and after ageing. Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction Analysis (XRD) were used to determine the degree of the m-ZrO2 transformation. Ageing resulted in an increase of the surface roughness, while the formation of monoclinic spots on the surface of the specimens was verified by surface uplifts in the AFM images. The peaks of the m-phase were clearly observed in the FTIR spectra while an average increase of 16% w.t. of the m-ZrO2 phase was recorded by XRD. Although, no sound lifetime predictions can be made from accelerated tests, based on the ISO standard that imposes that the m-phase should not exceed 25% wt after 5h at 134 °C and 2 bar pressure, it can be concluded that the tested ceramic resisted an extreme transformation that could negatively affect its clinical performance.

The Aesthetic Effect of All-Ceramic Pressed Crowns According to the Thickness and Color of the Materials Used - An In Vitro Study

2013 ◽  
Vol 587 ◽  
pp. 349-355
Author(s):  
Sergiu Drafta ◽  
Adelina Popescu ◽  
Vlad Naicu
Keyword(s):  
Human Eye ◽  
Color Parameters ◽  
Varying Thickness ◽  
Dental Abutment ◽  
All Ceramic ◽  
Materials Used ◽  
The Aesthetic ◽  
Ceramic Restorations ◽  
Final Color

The final color of all-ceramic restorations may be influenced by the varying thickness of the dental abutment. Eighty A2 color (MO and LT) ceramic discs and eighty A3.5 color and four different thicknesses composite discs of were produced. The measurements were performed using the Vita Easyshade spectrophotometer. The results were statistically analyzed. Conclusion: There are no significant differences (perceived by the human eye) of the color parameters in the CIE L*a*b* system when comparing different combinations.

Reliability and Properties of Ground Y-TZP-Zirconia Ceramics

2002 ◽  
Vol 81 (7) ◽  
pp. 487-491 ◽  
Author(s):  
R.G. Luthardt ◽  
M. Holzhüter ◽  
O. Sandkuhl ◽  
V. Herold ◽  
J.D. Schnapp ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
High Performance ◽  
Control Sample ◽  
Surface Grinding ◽  
Weibull Parameter ◽  
Zirconia Ceramics ◽  
Inner Surface ◽  
Cad Cam ◽  
Ceramic Restorations

Yttria-stabilized zirconia ceramics is a high-performance material with excellent biocompatibility and mechanical properties, which suggest its suitability for posterior fixed partial dentures. The hypothesis under examination is that the strength and reliability of Y-TZP zirconia ceramics are affected by the inner surface grinding of crowns, and vary with the grinding parameter. Flexural strength, surface roughness, and fracture toughness were determined on samples machined by face and peripheral grinding with varied feed velocities and cutting depths. Results have been compared with those on lapped samples. Analysis of variance and Weibull parameter were used for statistical analysis. It was found that inner surface grinding significantly reduces the strength and reliability of Y-TZP zirconia compared with the lapped control sample. Co-analysis of flexural strength, Weibull parameter, and fracture toughness showed counteracting effects of surface compressive stress and grinding-introduced surface flaws. In conclusion, grinding of Y-TZP needs to be optimized to achieve the CAD/CAM manufacture of all-ceramic restorations with improved strength and reliability.

scholarly journals Comparative analysis of flexural strength of abraded and polished porcelain surfaces – an in vitro study

2021 ◽  
Vol 14 (1) ◽  
pp. 61-67
Author(s):  
Prathibha Nandagiri ◽  
◽  
Mamidi Praveen ◽  
Shikha Singh ◽  
Monika Singh ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
The Other ◽  
Control Group ◽  
P Value ◽  
Diamond Bur ◽  
Significant Difference ◽  
Fine Diamond ◽  
Ceramic Restorations

Typically, prosthodontists adjust ceramic restorations glazed surface by grinding prior to insertion. Such alterations of surfaces are necessary for the correction of occlusal interferences. We aimed to evaluate and compare the change in flexural strength of ceramic surfaces after re-glazing and polishing. This study included 40 samples of ceramic blocks that were fabricated and glazed, and then fired in accordance with the manufacturer’s recommendations. The sample was randomly divided into four groups of 10 samples each. The first group was the control group with unaltered glazed samples. The second group was abraded with an extra-fine diamond bur followed by re-glazing, and the other two groups were polished with two commercially available polishing kits after abrading them with an extra-fine diamond bur. The samples were tested for their flexural strength using a universal testing machine. On the application of the F test on the means of all the groups, a value greater than 0.05 was found, which meant that there is no statistically significant difference in flexural strength values between the groups (P-value>0.05). Since the flexural strength values of the polished group were comparable to the other groups, polishing can be used instead of re-glazing for ceramic restorations. This reduces an additional clinical appointment for the patient and saves working time.

scholarly journals Comparative Analysis for Selection of Resin Luting Cements Based on Filler Content: An in vitro Study

2012 ◽  
Vol 13 (4) ◽  
pp. 481-486 ◽  
Author(s):  
Mandava Ramesh Babu ◽  
Vajapeyayajula RaviKiran ◽  
V Vinod ◽  
Devabhaktuni Saraswathi ◽  
Venugopal N Rao
Keyword(s):  
Comparative Analysis ◽  
Flexural Strength ◽  
Filler Content ◽  
Filler Loading ◽  
Luting Cements ◽  
Luting Agents ◽  
Luting Cement ◽  
All Ceramic ◽  
Selection Of

ABSTRACT Context Resin luting of all-ceramic restorations results in increased performance; however, the strengthening mechanism and the role of the mechanical properties of the resin are not fully understood. Objective The aim of this study was to investigate the effect of filler content on the flexural properties of resin luting agents and thereby selecting an appropriate resin luting cement. Materials and methods Three esthetic resin luting agents studied were Calibra (Dentsply); RelyX ARC and Panavia F. Ten beam-shaped specimen (L × W × H: 30 × 8 × 2 mm) were made for each of the material tests carried out. The specimens were stored in distilled water for 24 hours at 37°C. The specimens were then tested for flexural strength (MPa) and flexural modulus (GPa) using the three-point bending method on a universal material testing machine at a cross head speed of 0.5 mm/min. Data obtained were statistically analyzed using ANOVA followed by post-hoc - Tukey's test with p < 0.05 for statistical significance. Results Increase in mean strength related to an associated increase in the elastic modulus which in turn was related to the filler loading of the resin luting cements. Conclusion Strength and performance of resin-cemented allceramic restoration can be enhanced by the use of a resin luting cement having increased filler content. Clinical implications Resin-composite cements may be most suitable for adhesively bonded restorations, where margins are placed on supragingival enamel, and where ultimate strength and energy absorption are paramount. The selection criteria for a resin cement depends on its flexural strength. To a great extent, the flexural strength is dependent on the filler loading of the resin luting cement. Key message Fracture of brittle all-ceramic restoration can be prevented by using resin luting cement with higher filler loading. In other words, any resin luting cement with higher filler content has an improved performance in terms of clinical function and durability. How to cite this article Babu MR, RaviKiran V, Vinod V, Saraswathi D, Rao VN. Comparative Analysis for Selection of Resin Luting Cements Based on Filler Content: An in vitro Study. J Contemp Dent Pract 2012;13(4):481-486.

scholarly journals Evaluation of zirconia bonding to veneering porcelain

2014 ◽  
Vol 60 (02) ◽  
pp. 51-56 ◽  
Author(s):  
Aneta Mijoska ◽  
Mirjana Popovska
Keyword(s):  
Zirconium Dioxide ◽  
Adhesive Bonding ◽  
High Strength ◽  
Dental Tissues ◽  
Dental Crowns ◽  
Standard Procedures ◽  
All Ceramic ◽  
Hard Dental Tissues ◽  
Ceramic Restorations

Zirconium dioxide as core ceramic material for dental crowns and bridges, possess high strength, chemical stability and superior aesthetics after veneering. Veneering ceramic is considered to be the weakest part of all-ceramic restorations. The adhesion between the core and veneering porcelain is based on the manner in which the connection occurs in metal-ceramic structures. Standard procedures for connecting zirconia to hard dental tissues and veneering materials do not achieve the required strength of bonding. The aim of the paper is to investigate different surface treatments of the zirconium dioxide ceramic core and find the best, for achieving highest adhesive bonding values to veneering porcelain. The study was primarily designed to investigate the bonding strength of the veneering porcelain to zirconia with in vitro Macro shear bond strength test. The specimens with different surface treatment of the zirconia were divided in five groups of twelve according to the treatment of zirconium surface and results showed highest bonding values for specimens treated with Rocatec system.

scholarly journals Evaluation of wear characteristics of natural teeth opposing all-ceramic restorations: An in vitro study

2018 ◽  
Vol 4 (3e) ◽  
pp. 287-292
Author(s):  
Jayasree Komala ◽  
Sudhakar Reddy T ◽  
Subhasri Kandhati ◽  
Keerthi Edulapalli
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Wear Characteristics ◽  
All Ceramic ◽  
Natural Teeth ◽  
Ceramic Restorations
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