• The Journal of Advanced Prosthodontics
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• 제11권5호
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• pp.297-304
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• 2019

PURPOSE. This in vitro study investigated the repair bond strength of the zirconia ceramic after different aging conditions. MATERIALS AND METHODS. In order to imitate the failure modes of veneered zirconia restorations, veneer ceramic, zirconia, and veneer ceramic-zirconia specimens were prepared and were divided into 4 subgroups as: control ($37^{\circ}C$ distilled water for 24 hours ) and 3000, 6000, 12000 thermal cycling groups (n=15). Then, specimens were bonded to composite resin using a porcelain repair kit according to the manufacturer recommendation. The repair bond strength (RBS) test was performed using a universal testing machine (0.5 mm/min). Failure types were analyzed under a stereomicroscope. Two-way ANOVA and Bonferroni test were used for statistical analysis. RESULTS. The RBS values of zirconia specimens were statistically significant and higher than veneer ceramic and veneer ceramic-zirconia specimens in control, 3000 and 6000 thermal cycling groups (P<.05). When 12000 thermal cycles were applied, the highest value was found in zirconia specimens but there was no statistically significant difference between veneer ceramic and veneer ceramic-zirconia specimens (P>.05). Veneer ceramic specimens exhibited cohesive failure types, zirconia specimens exhibited adhesive failure types, and veneer ceramic-zirconia specimens exhibited predominately mixed failure types. CONCLUSION. Thermal cycling can adversely affect RBS of composite resin binded to level of fractured zirconia ceramics.

• 대한치과보철학회지
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• 제52권2호
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• pp.136-142
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• 2014

최근 많이 이용되고 있는 지르코니아-도재 수복물은 그 적용범위가 점차로 증가하고 있다. 임상연구결과에서 지르코니아 코어는 매우 높은 성공율을 보이고 있으나 코어 위에 축성되는 전장도재는 기존에 이용되어온 금속-도재 수복물에 비해 높은 파절빈도를 나타내고 있다. 이러한 파절의 원인으로 여러가지 요소가 거론되고 있으나 아직 명확하게 설명하고 있지는 못하다. 최근 전장도재 축성 후 냉각과정에서 잔존하는 잔류응력이 전장도재의 파절에 영향을 미칠 수 있다는 연구결과가 속속 발표되고 있다. 본 고찰에서는 잔류응력이 무엇이며 도재 축성 후 냉각과정에서 어떤 기전을 통해 전장도재 내에 잔류응력이 발생하는지, 또한 기존의 금속-도재 수복물에서 발생하는 잔류응력과는 어떤 차이가 있는지 문헌고찰을 통해 살펴보고자 한다.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.451-455
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• 2014

PURPOSE. The most common failure seen in restorations with a zirconia core is total or layered delamination of the ceramic veneer. In the present study, the shear bond strengths between veneering ceramics and colored zirconia oxide core materials were evaluated. MATERIALS AND METHODS. Zirconia discs ($15{\times}12{\times}1.6mm$) were divided into 11 groups of 12 discs each. Groups were colored according to the Vita Classic scale: A3, B1, C4, D2, and D4. Each group was treated with the recommended shading time for 3 s, or with prolonged shading for 60 s, except for the control group. Samples were veneered with 3 mm thick and 3.5 mm in diameter translucent ceramic and subjected to shear test in a universal testing machine with a crosshead speed of 1 mm/min. One-way analysis of variance (ANOVA) and Tukey's HSD tests were used for comparisons of the groups having the same shading times. A paired t-test was used for groups of the same color (3 s/60 s). RESULTS. Among the 11 groups investigated C4 (3 s) had the highest bond strength with a value of 36.40 MPa, while A3 (3 s) showed the lowest bond strength with a value of 29.47 MPa. CONCLUSION. Coloring procedures can affect zirconia/ceramic bond strength. However, the results also showed that bond strengths of all the investigated groups were clinically acceptable.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.335-341
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• 2020

본 연구의 목적은 shear bond strength을 이용하여 pressed lithium disilicate 전장도재와 zirconia core의 접착을 비교 분석하는 것이다. Zirconia blank(Zirtooth, HASS, Gangneung, Korea)에 각 pressed ceramic(IPS e.max Zirpress, Vita PM9, GC Initial IQ, HASS Rosetta UP)이 적용된 시편을 제작하였다(N=40). 전단결합강도를 비교 평가하기 위해 The Schmitz-Schulmeyer test method을 이용하였고 산출된 파괴하중의 값을 분석했다. 산출된 네 가지 전단결합강도 값들 간의 평균 비교는 일원분산분석(one-way ANOVA)을 통해 이루어졌고, Tukey의 사후검정을 실시하여 서로 간의 평균 차이가 통계적으로 유의함을 검증하였다. 또 파절면의 3D 분석을 통하여 파괴 표면을 관찰하여, 그 파괴 양상도 분류하였다. 실험군별 전단결합강도는 IPS e.max Zirpress 16.69±3.11MPa, VITA PM9 14.21±3.63MPa, GC Initial IQ 11.17±2.92MPa, HASS Rosetta SM 27.90±5.71MPa이었으며, Lithium disilicate ceramic veneer(HASS Rosetta SM)의 결합 강도는 다른 제품들보다 통계적으로 유의하게 높았다(p<0.05). 또, 파괴면의 유형 분류 결과, 모든 시편에서 cohesive 파괴는 관찰되지 않았고 주로 adhesive와 cohesive가 같이 조합된 파괴 유형이 관찰되었다. 본 연구 결과에 의해서 pressed lithium disilicate 전장도재가 기존의 pressed to zirconia system보다 나은 접착력을 보여주었다.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.259-264
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• 2018

PURPOSE. The purpose of this study was to evaluate the effect of the zirconia surface architecturing technique (ZSAT) on the bond strength between veneering porcelain and zirconia ceramic. MATERIALS AND METHODS. 20 sintered zirconia ceramic specimens were used to determine the optimal surface treatment time, and were randomly divided into 4 groups based on treatment times of 0, 1, 2, and 3 hours. After etching with a special solution, the surface was observed under scanning electron microscope, and then the porcelain was veneered for scratch testing. Sixty 3 mol% yttria-stabilized tetragonal zirconia polycrystal ceramic blocks were used for tensile strength testing; 30 of these blocks were surface treated and the rest were not. Statistical analysis was performed using ANOVA, the Tukey post-hoc test, and independent t-test, and the level of significance was set at ${\alpha}=.05$. RESULTS. The surface treatment of the zirconia using ZSAT increased the surface roughness, and tensile strength test results showed that the ZSAT group significantly increased the bond strength between zirconia and veneering porcelain compared to the untreated group (36 MPa vs. 30 MPa). Optimal etching time was determined to be 2 hours based on the scratch test results. CONCLUSION. ZSAT increases the surface roughness of zirconia, and this might contribute to the increased interfacial bond strength between zirconia and veneering porcelain.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.415-422
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• 2014

PURPOSE. The purpose of this study was to evaluate and compare the translucency of shaded zirconia allceramic systems. MATERIALS AND METHODS. Translucency of 3 different zirconia all-ceramic systems colored by different techniques was compared with a lithium disilicate glass-ceramic (IPS e.max Press). Square-shaped specimens with 0.5 mm thickness were fabricated from In-Ceram YZ, ICE Zirkon and Katana systems in A1, A2 and A3.5 shades according to Vitapan Classical shade tab (n=11). Specimens were then veneered and glazed with corresponding veneer ceramic recommended by each zirconia system manufacturer and the total thickness was set to 1.5 mm. Translucency measurements were performed with VITA Easyshade Compact spectrophotometer after each stage and translucency parameter was calculated. Data were statistically analyzed with repeated measures ANOVA and Tukey multiple comparison test. RESULTS. The control group was significantly more translucent than the zirconia systems (P<.05). ICE Zirkon cores showed the least translucency; neither In-Ceram YZ nor Katana systems were superior to each other in terms of translucency. Translucency of all specimens was decreased after veneering, and the translucency rankings were changed. CONCLUSION. Coloring technique did not have a significant effect on translucency of zirconia cores. Although zirconia systems were less translucent than lithium disilicate glass ceramic, they had partial translucency and there were translucency differences among the zirconia systems. Chroma affected the translucency of precolored zirconia cores.

• The Journal of Advanced Prosthodontics
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• 제11권1호
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• pp.65-74
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• 2019

PURPOSE. To evaluate and compare the effect of different materials and techniques on the shear bond strength of veneering ceramic materials to zirconia. MATERIALS AND METHODS. 136 sintered zirconia cubes were prepared and randomly divided into four study groups according to corresponding methods of surface treatment and materials: GLN (grinding followed by laser scanning using Noritake Cerabien ZR), SLN (sandblasting followed by laser scanning using Noritake Cerabien ZR), GLV (grinding followed by laser scanning using VITA VM 9), and SLV (sandblasting followed by laser scanning using VITA VM 9). Spraying technique was performed to coat the core. Profilometer, SEM, XRD, EDS, universal testing machine, and stereomicroscope were used to record surface roughness Ra, surface morphology, phase transformation, elemental compositions, shear bond strength SBS values, and failure types, respectively. Specimens were investigated in unaged (not immersed in artificial saliva) and aged (stored in artificial saliva for a month) conditions to evaluate SBS values. RESULTS. Grinding and GLN as first and second surface treatments provided satisfactory Ra values in both conditions ($1.05{\pm}0.24{\mu}m$, $1.30{\pm}0.21{\mu}m$) compared to sandblasting and other groups (P<.05). The group GLN showed the highest SBS values in both conditions ($30.97{\pm}3.12MPa$, $29.09{\pm}4.17MPa$), while group SLV recorded the lowest ($23.96{\pm}3.60MPa$, $22.95{\pm}3.68Mpa$) (P<.05). Sandblasting showed phase transformation from t-m. Mixed failure type was the commonest among all groups. CONCLUSION. GLN showed to be a reliable method which provided satisfactory bond strength between the veneer ceramic and zirconia. This method might preserve the integrity of fixed dental crowns.

• 대한치과기공학회지
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• 제43권1호
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• pp.6-12
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• 2021

Purpose: This study aimed to compare the shear bond strength between zirconia cores and veneer ceramics as per the sand blasting and liner treatments. Methods: The following 4 groups of zirconia-veneering ceramic specimens were prepared: (1) Group I, untreated; (2) Group II, with 110 ㎛ aluminium oxide (Al2O3) sandblasting; (3) Group III, with liner (IPS e.max ZirLiner; Ivoclar Vivadent); and (4) Group IV, with 110 ㎛ Al2O3 sand blasting and liner. Surface roughness was measured for all the prepared specimens, and the surface morphology was observed using a scanning electron microscope. All the samples (n=40) were fixed with measuring jigs, and shear bond strengths were obtained using a universal testing machine with a crosshead speed of 0.5 mm/min. The shear bond strength data were analyzed using one-way analysis of variance and t-test. The post hoc comparison was performed using the Tukey's test (α=0.05). Results: A significant difference in the surface roughness was observed between the specimens of groups I and II (p<0.05). Surface treatment with liner and sandblasting showed higher shear bond strength between zirconia core and veneering ceramic (p<0.05). Conclusion: The sand blasting and liner treatment increased the shear bond strength between zirconia core and veneering ceramic.

• The Journal of Advanced Prosthodontics
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• 제1권3호
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• pp.129-135
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• 2009

STATEMENT OF PROBLEM. Zirconia-based restorations have the common technical complication of delamination, or porcelain chipping, from the zirconia core. Thus the shear bond strength between the zirconia core and the veneering porcelain requires investigation in order to facilitate the material's clinical use. PURPOSE. The purpose of this study was to evaluate the bonding strength of the porcelain veneer to the zirconia core and to other various metal alloys (high noble metal alloy and base metal alloy). MATERIAL AND METHODS. 15 rectangular ($4\times4\times9mm$) specimens each of zirconia (Cercon), base metal alloy (Tillite), high noble metal alloy (Degudent H) were fabricated for the shear bond strength test. The veneering porcelain recommended by the manufacturer for each type of material was fired to the core in thickness of 3mm. After firing, the specimens were embedded in the PTFE mold, placed on a mounting jig, and subjected to shear force in a universal testing machine. Load was applied at a crosshead speed of 0.5mm/min until fracture. The average shear strength (MPa) was analyzed with the oneway ANOVA and the Tukey's test ($\alpha$= .05). The fractured specimens were examined using SEM and EDX to determine the failure pattern. RESULTS. The mean shear strength ($\pm\;SD$) in MPa was 25.43 ($\pm\;3.12$) in the zirconia group, 35.87 ($\pm\;4.23$) in the base metal group, 38.00 ($\pm\;5.23$) in the high noble metal group. The ANOVA showed a significant difference among groups, and the Tukey' s test presented a significant difference between the zirconia group and the metal group. Microscopic examination showed that the failure primarily occurred near the interface with the residual veneering porcelain remaining on the core. CONCLUSION. There was a significant difference between the metal ceramic and zirconia ceramic group in shear bond strength. There was no significant difference between the base metal alloy and the high noble metal alloy.

• 대한치과기공학회지
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• 제32권4호
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• pp.341-350
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• 2010

Purpose: This study focused on achieving desired shades by combining zirconia core with different thickness porcelain in order to make dental prostheses effectively. Methods: White and colored $LAVA^{TM}$ All Ceramic (3M-ESPE, Seefeld, Germany), and Zirkonzahn (Bruneck, Italy) Trans and prettau were used to have Zirconia. LAVATM Ceram (3M-ESPE, Germany) and ICE (Zirkonzahn, Italy) powder were used to have the porcelain. We made quadrilateral specimen of thickness 0.3mm, 0.5mm, 0.7mm and diameter 10 to use zirconia ceramics system of 2 kinds that color tone reappearance way is different and produced total 120 specimens to 4 experimental groups. We used Spectrophotometer to analyze color tone. Data's value getting by dispersal colorimetry period found L*, a*, b* value using Excel program. We used one-way ANOVA to use SPSS WIN 12.0 program. Results: All L*, a*, b* indexes of zirconia core and porcelain veneer in LAVA group and Zirkonzahn group were different. When you combine the white zirconia core of LAVA group with a porcelain veneer, the thickness of the porcelain must be more than 0.5mm to meet the standard target. When all the colored zirconia cores of LAVA group were combined with porcelain veneers, there was no significant difference from the standard target. When the zirconia cores of Zirkonzahn group are combined with porcelain veneers, the thinner thicknesses were closer to the standard tab than thicker thicknesses; however, there was a significant difference in all combinations, with Delta E* value indicating more than 3. Conclusion: When it comes to colored zirconia, which is the most popular, the thicknesses of both a core and a dentin veneer must be more than 0.3mm to get an appropriate shade. There is more possibility to get desirable shades when the thicknesses of a white core are thinner; however, they would be vulnerable to the environment and lose their color. When combine a zirconia core with a dentin veneer, using Zirkonzahn group needs more considerations in order to meet the standard target.