• Journal of Technologic Dentistry
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• v.35 no.1
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• pp.19-27
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• 2013

Purpose: The aim of this research was to evaluate the shear bond strength of different zirconia veneering ceramics with and without liner glass materials to yttria partially-stabilized tetragonal zirconia polycrystalline(Y-TZP). Methods: Five co mmercial zirconia veneering ceramics were used in this study, E-Max(EM), Creation ZI(CR), Cercon ceram kiss(CE), Triceram(TR) and Zirkonzahn ICE(ZI). All samples were prepared according to manufacturer's instructions. Experimental industrially manufactured Y-TZP ceramic blocks(diameter: 2.7 mm; height: 13.5 mm) were used in this study. Shear bond strength between zirconia ceramic coping and zirconia veneering ceramics were evaluated by the push-shear bond test. The fracture load data were analyzed using ANOVA and Scheffe's test(${\alpha}$=0.05). The fractured surfaces of zirconia core ceraimc and zirconia veneering ceramics were observed using a scanning electron microscope(SEM). Results: The mean shear bond strengths ranged from 20 MPa ($20.12{\pm}6.34$ MPa) to 66.6 MPa ($66.62{\pm}10.01$ MPa). The Triceram(TRG) showed the highest value and Creation ZI(CR) showed the lowest value. In all groups, Zirconia liner and glass material groups was significantly higher shear bond strength than without liner(P<0.05), with the exception of Cercon ceram kiss(CE)groups. Conclusion: Zirconia bonding materials may have the advantage of improved bond strength between zirconia ceramic core and veneering ceramics.

• The Journal of the Korean dental association
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• v.51 no.1
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• pp.6-11
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• 2013

Dental ceramics is well known to have excellent esthetics, biocompatibility as well as high compressive strength. However, the fragility of ceramics against tensile and shear loads leading to the delayed fracture of micro crack on ceramic surface and the backwardness of ceramic fabrication technique limit the usage of ceramic materials in dentistry. Among all ceramic materials, zirconia has been introduced to overcome the drawback of conventional dental ceramics in the field of dentistry due to the nature of zirconia featuring proper opalescence and high fracture toughness. Also, novel manufacturing techniques enable ceramic materials to prepare high esthetic anterior and posterior all ceramic system. In this paper, it is introduced and discussed that novel techniques characterizing the bond strength between zirconia core and veneering ceramics and analyzing the fluorescence of dental ceramics in order to overcome the gap between the results of basic research and the feasibility of the results in the field of dental clinics.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.2
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• pp.119-130
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• 2007

Purpose: This investigation was designed to estimate the flexure strength, density, and microstructure of the colored and uncolored zirconia oxide ceramics for fixed partial denture. Material and Methods: LAVATM All Ceramic(3M-ESPE, USA), Cercon Smart Ceramic(Dentsply, USA), and Z-match Ceramic(DentAim, Korea) were used for this study. All specimen was fabricated by ASTM C1161. After preparing $25{\times}2{\times}1.5mm$ of rectangular column and sitting rectangular column on universal test machine (UTM), external supporting point distance is 20.0 mm, internal supporting point distance is 10.0 mm. Specimen was loaded with 0.2 mm/min of cross head speed until fracture and at the time of broken of specimen, measuring loading value with PC software. Results: The results were obtained as follows: 1. Flexure strength of uncolored zirconia was higher than that of colored zirconia. 2. In uncolored zirconia, flexure strength of LAVATM Ceramic was more higher than the other ceramics, and it showed statistical difference between LAVATM Ceramic and Cercon Smart Ceramic (P<0.05). 3. In colored zirconia, flexure strength of LAVATM Ceramic was more higher than the other ceramics too, but they did not show statistical difference (p>0.05). 4. In Weibull analysis, Characterastic strength was showed highest value to uncolored LAVATM Ceramic and lowest value to Z-match ceramic, and Weibull modulus(m) of uncolored zirconia was higher than that of colored zirconia. 5. In XRD analysis, all group except Z-match showed high peak of t-ZrO2 but they did not show m-ZrO2. Colored zirconia group showed lower peak of t-ZrO2 than that of uncolored zirconia group.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.335-340
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• 2010

This study was performed to evaluate the fracture strength of the dental zirconia veneering ceramics for zirconia ceramic core. Six commercial zirconia veneering ceramics were used in this study, namely E-Max(Ivoclar vivadent, Inc, Liechtenstein), Creation ZI(KLEMA Dental produckte GmbH, Austria), Cercon ceram kiss(Degudent, GmbH, Hanau-Wolfgang, Germany), Triceram(Dentaurum, Ispringen, Germany), Zirkonzahn(Zirkonzahn GmbH, Italy), Zirmax(Alpadent, korea). All samples were prepared according to the relevant instructions of manufacture. Disc specimens were prepared to the final dimensions of 17 mm in diameter and 1.5 mm in thickness. The biaxial flexure strength test was conducted using a ball-on-three-ball method. All specimens were tested in a moisture-free environment. Average flexural strengths were analyzed with Weibull analysis and one-way analysis of variance(ANOVA). Significant differences were founded between the mean flexural strength values of five commercials zirconia veneering ceramics and the other. The flexural strengths and Weibull modulus were similar to those of five groups E-Max(EM), Creation ZI(CR), Cercon ceram kiss(CE), Triceram(TR), Zirkonzahn(ZI) with the exception of Zirmax(ZM). The biaxial flexural strength from Cercon ceram kiss(CE) was higher than those of other groups. Fracture analysis showed similar results for these five groups.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.365-366
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• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.

• The Journal of the Korean dental association
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• v.49 no.5
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• pp.279-285
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• 2011

Currently there is no dental ceramic material can be used in all dental situations need to be restored. However, in view of recent clinical reports, the most viable alternative is zirconia ceramic. Clinical success of dental zirconia restorations strongly depends on proper selection of materials, accurate laboratory procedure and final cementation, which can be achievable with the correct understanding of zirconia. As dental materials, zirconia ceramics have a very bright future, because they are being used increasingly in the anterior region as implant fixtures, as well as crown and bridge restorations and implant abutments. Many dental ceramics showing poor clinical performance have been gone from the dental market. However, in terms of outstanding mechanical properties and esthetic nature, new dental materials can replace zirconia ceramics will not be available in the foreseeable future.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.384-394
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• 2015

The purpose of this study was to evaluate the push-shear bond strength between five commercial zirconia veneering ceramics and zirconia core cylinder, and to investigate the effect of biaxial flexural strength and zirconia liner glass treatments. The biaxial flexural strengths of the veneering ceramics were evaluated by a piston-on-three-ball test. The bond strengths between the Y-TZP cylinder and zirconia veneering ceramics were evaluated using the push-shear bond strength test. The data was analyzed using two-way ANOVA and Scheffe's test. The biaxial flexural strength of Cercon ceram kiss (CE) was higher than those of the other groups. The glass-treated and Triceram zirconia groups showed the highest value and the Creation ZI(CR) showed the lowest. In all groups, the liner glass treatment groups showed significantly higher push-shear bond strength than those without(P<0.05). The liner glass treatments of zirconia can improve the bond strength between the zirconia ceramic core and veneering ceramics.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3898-3903
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• 2024

There is a lack of available data on the radioactivity levels of these materials, despite the potential risks they may pose to patients, dental technicians, and dentists. A total of forty samples were collected from different dental markets in Egypt. Using an NaI(Tl) detector, the gamma-ray spectrometer measured the activity levels of uranium-238, radium-226, thorium-232, and potassium-40. The findings revealed that the mean concentration of ²³⁸U (below the minimum detectable activity, MDA), ²²⁶Ra (135 ± 5 and 132 ± 5 Bq/kg), ²³²Th (187 ± 4 and 243 ± 8 Bq/kg), and ⁴⁰K (1560 ± 52 and 2501 ± 89 Bq/kg) in feldspar and zirconia (ZrO₂) dental ceramic samples, respectively, were all within the limits established by the International Organization for Standardization (ISO) and the European Commission (EC). The use of feldspar and zirconia dental ceramics to restore all teeth would result in an estimated maximum beta dose of 1.5 mGy/year to the oral tissue. The results suggest that there is no cause for concern regarding any additional beta dose to the oral cavity from the use of feldspar and zirconia dental ceramics.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.296-302
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• 2014

Objectives: It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of $CO_2$ and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods: In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness) were assigned to 3 groups (n = 15). In control group (CNT) no laser treatment was used. In groups COL and EYL, $CO_2$ and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results: The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were $8.65{\pm}1.75$, $12.12{\pm}3.02$, and $5.97{\pm}1.14MPa$, respectively. Data showed that application of $CO_2$ and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001). The highest bond strength was recorded in the COL group (p < 0.0001). In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions: Pretreatment of zirconia ceramic via $CO_2$ and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the $CO_2$ laser treated samples.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.219-224
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• 2011

Purpose: The current study focused on investigating color change of dental zirconia block with respect to the block coloring time. Methods: Three types of dental zirconia blocks(Zirtooth, Pearl-HT, D-Max) were tinted with coloring agent under four different time condition (0 minutes, 1 minutes, 10 minutes, 30 minutes). The quantitative evaluation of the tinted dental zirconia blocks was conducted with spectrophotometer. Results: The Zirtooth and D-Max blocks showed lower H value. The Pearl-HT blocks showed poor reflectivity(L value). Conclusion: The study of color change of zirconia block, which consists the substructure of all ceramic Crown, is applicable for deciding appropriate coloring condition when fabricating one layer ceramic Crown or double layer ceramic Crown.