• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.358-363
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• 2015

Previously, the usage of monolithic zirconia in anterior restoration was limited because of problems such as the monotony of tones and shades which would compromise the outcome of esthetic purpose. Zirconia was merely used as a coping with additional porcelain veneering whereas porcelain chipping cannot be evaded. Recently, with the improvement of monolithic zirconia, the various translucency and tones made it possible to use zirconia for anterior restoration. In this case, a male patient of 63 years old received a full mouth rehabilitation with monolithic zirconia. After a period of time usage, the outcome showed a favorable result functionally and esthetically.

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.449-454
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• 2015

The fabrication process of zirconia gel-casting was studied to obtain dense zirconia on a large scale or with complicated shapes. As an experimental parameter, two different particle sizes ($0.1{\mu}m$ and $0.7{\mu}m$) of zirconia powder were applied to the gel-casting process. The viscosity behavior of slurries incorporating 40 vol% of zirconia powder was examined as a function of the dispersant content and the solid load to determine the optimum dispersion conditions. In addition, the gelation time with an initiator, the de-binding behavior, and the main factors affecting densification were examined. The densification of the gel-casted zirconia green body depended on the mixing ratio between the monomer and the dimer and on the zirconia particle size. A green body with a small particle size of $0.1{\mu}m$ showed less densification, with a relative density of 93%. This may be due to the excess number of bubbles created through interactions between the larger particle surface and polymer additives during the ball-milling process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.3
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• pp.99-104
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• 2003

Alumina/zirconia-glass composites prepared by melt-infiltration were investigated to evaluate the influence of zirconia addition on mechanical and optical properties of the composites and glass penetration kinetics. The infiltration distance was parabolic with respect to time as described by the Washburn equation and the penetration rate constant, K, decreased due to the reduction In pore size as the amount of zirconia rose. The zirconia addition increased lightness ($L^*$) but reduced K, transmittance and color sharpness ($C^*$) It can be concluded that the zirconia addition was not effective to the mechanical properties of the composites due to the increase in porosity even though the toughness of the composites increased when zirconia was added up to 15 wt%.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.283-289
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• 2011

Purpose: The purpose of this study was to evaluate flexural strength of full zirconia crown using block after clinical work. Methods: The three point bending test was used to measure the flexural strength of zirconia block. Statistical analysis was done using the Statistical Package for Social Sciences version 19.0 for Windows. As for the analysis methods, the study used analysis of variance, Tukey's test. Results: The ave Rage value of flexural strengths of WIELAND, Zirkonzahn, Hass, D-MAX were 516.2 MPa, 612.6MPa, 566.2MPa, 744.6MPa. The ave Rage value of Surface Roughness of WIELAND, Zirkonzahn, Hass, D-MAX were 0.39Ra, 0.33Ra, 0.33Ra, 0.47Ra. Conclusion: Flexural strength of zirconia block decreased after clinical work. Flexural strength of zirconia block is equal to or higher than flexural strength of dental metal, so zirconia block can be used as dental material.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.91-94
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• 2003

Ceramic femoral heads in the total hip replacement have been developed to reduce the polyethylene liner wear. Alumina and zirconia (3Y-TZP) are using in clinical application worldwide and there are many good test reports. However, alumina has a risk of catastrophic failure, and zirconia has the low temperature degradation in spite of enhanced fracture toughness. Recently, novel zirconia/alumina composite having low temperature degradation-free character and high fracture tough . was developed and it leads the lower wear 3f polyethylene than alumina and zirconia. In the present study, in order to optimise the microstructure of low temperature degradation (LTD)-free zirconia/alumina composite for the best wear resistance of polyethylene, various compositions of (LTD)-free zirconia/alumina composites were fabricated, and the sliding wear of UHMWPE against these novel composites were examined and compared with that against alumina and zirconia ceramics used for total hip joint heads.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.1
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• pp.4-14
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• 2016

Although CAD/CAM technology has been used in dentistry for more than decades, the present CAD/CAM dentistry is still quite inefficient or unesthetic. Zirconia restoration has faced with two contradictory words, 'Efficiency' and 'Esthetics'. One can consider monolithic zirconia restoration to be efficient with CAD/CAM. The monolithic zirconia restoration, however, is rarely esthetic due to the current limitations with zirconia. On the contrary, porcelain build-up is almost indispensible in fabricating esthetic restoration, especially in anterior region. In this article, the current status of monolithic zirconia restoration and clinical cases will be presented.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.306-316
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• 2018

Monolithic zirconia has been widely used in fixed partial dentures due to high strength and fracture toughness. Nevertheless, the usage of monolithic zirconia in anterior restoration was limited because of opacity. Recently, esthetic monolithic zirconia blocks are developed by improving translucency and using various shading systems. Manufacturer introduces 3M $Lava^{TM}$ Esthetic with increased cubic phase and fluorescent ingredients is more esthetic than previous monolithic zirconia. This case report describes favorable anterior restorations using translucent monolithic zirconia.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.307-312
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• 2020

Application of ceramic materials for fabrication of dental restoration materials has been a focus of interest in the field of esthetic dentistry. The ceramic materials of choice are glass ceramics, spinel, alumina, and zirconia. The development of yttrium tetragonal zirconia polycrystal (YTZP)-based systems is a recent addition to all-ceramic systems that have high strength and are used for crowns and fixed partial dentures. Computer-aided design/computer-aided manufacturing (CAD/CAM)-produced, YTZP-based systems are popular with respect to their esthetic appeal for use in stress-bearing regions. The highly esthetic nature of zirconia and its superior physical properties and biocompatibility have enabled the development of restorative systems that meet the demands of today's patients. Many in vitro trials have been performed on the use of zirconia; however, relatively fewer long-term clinical studies have been published on this subject. The use of zirconia frameworks for long-span fixed partial dentures is currently being evaluated; in the future, more in vivo research and long-term clinical studies are required to provide scientific evidence for drawing solid guidelines. Further clinical and in vitro studies are required to obtain data regarding the long-term clinical use of zirconia-based restorations.

• Journal of Technologic Dentistry
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• v.44 no.4
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• pp.118-125
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• 2022

Purpose: The color of dental zirconia is very important in terms of aesthetics. To reproduce the color tone, a colorant is applied to zirconia to express the color tone. I would like to point out that the color, brightness, and saturation of the colorant used to express the color A3 may vary depending on the manufacturer. Methods: Each zirconia block received a total of 25 circular specimens for the experiment. The zirconia specimen was then deposited by colorant type to reproduce the color tone. Color differences and translucency were measured using a spectrophotometer. To compare and analyze the zirconia color according to the type of colorant, one-way ANOVA was used. Results: For each type of zirconia colorant, there was no statistically significant difference in translucency or b^* (p>0.05). There was a statistical difference in L^* and a^* (p<0.05). Conclusion: The ΔE^*ab (D65) value is less than 5.5 or less, and the color difference is within an acceptable range.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1028-1034
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• 2002

Spinel/zirconia-glass composites prepared by melt-infiltration were fabricated to investigate the effect of zirconia addition on mechanical and optical properties of the composites. The infiltration distance was parabolic with respect to time as described by the Washburn equation and the penetration rate constant, K, decreased due to the reduction in pore size as the amount of zirconia rose. Although the optimum strength(308 MPa) of the Spinel/zirconia-glass composites was observed when the zirconia was added up to 20 wt%, K and transmittance decreased as the zirconia content rose. In conclusion, it suggested that the positive effect of strength as a result of the addition of zirconia was not effective.