• 대한치과보철학회지
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• 제39권6호
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• pp.641-658
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• 2001

All-ceramic restorations have become an attractive alternative to porcelain-fused-to-metal crowns. In-Ceram, and more recently IPS Empress 2 were introduced as a new all-ceramic system for single crowns and 3-unit fixed partial dentures. But their strength and marginal fit are still an important issue. This study evaluated the fracture resistance and marginal fit of three systems of 3 unit all-ceramic bridge fabricated on prepared maxillary anterior resin teeth in vitro. The 3 all-ceramic bridge systems were: (1) a glass-infiltrated, sintered alumina system (In-Ceram) fabricated conventionally, (2) the same system with copy-milled alumina cores (copy-milled In-Ceram), (3) a heat pressed, lithium disilicate reinforced glass-ceramic system (IPS Empress 2). Ten bridges of each system with standardized design of framework were fabricated. All specimens of each system were compressed at $55^{\circ}$ at the palatal surface of pontic until catastrophic fracture occurred. Another seven bridges of each system were fabricated with standard method. All of the bridge-die complexes were embedded in epoxy resin and sectioned buccolingually and mesiodistally. The absolute marginal discrepancy was measured with stereomicroscope at ${\times}50$ power. The following results were obtained: 1. There was no significant difference in the fracture strength among the 3 systems studied. 2. The Weibull modulus of copy-milled In-Ceram was higher than that of In-Ceram and IPS Empress 2 bridges. 3. Copy-milled In-Ceram($112{\mu}m$) exhibited significantly greater marginal discrepancy than In Ceram ($97{\mu}m$), and IPS Empress 2 ($94{\mu}m$) at P=0.05. 4. The lingual surfaces of the ceramic crowns showed smaller marginal discrepancies than mesial and distal points. There was no significant difference between teeth (incisor, canine) at P=0.05. 5. All-ceramic bridges of three systems appeared to exhibit sufficient initial strength and accept able marginal fit values to allow clinical application.

• 대한치과보철학회지
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• 제46권6호
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• pp.577-585
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• 2008

STATEMENT OF PROBLEM: The discoloration of anterior teeth restoration is one of the material problems demanding retreatment. OBJECTIVES: To evaluate the color stability and affecting factors on esthetic restorative materials when subjected to accelerated aging. MATERIAL AND METHODS: This study was conducted using porcelain disks (IPS Empress 2-glazed, IPS Empress 2-polished), direct restorative resin disks (SYNERGY Duo) and indirect restorative resin disks (Sinfony, TESCERA ATL). Accelerated aging was done by precipitating the specimens in 38.C distilled water and irradiating with xenon light, and the total irradiation was 397.98 KJ/mm. Color and microhardness change of the specimens were measured before accelerated aging and after 100 hours, 200 hours and 300 hours of accelerated aging, and Surface of the specimens were examined with SEM before and after 300 hours of accelerated aging. RESULTS: 1. After 300 hours' accelerated aging, a ${\Delta}E$ value was 3.3 or lower in IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony. 2. After 300 hours' accelerated aging, gloss was lost and surface changes including microcracks were observed in TESCERA ATL and SYNERGY Duo, and color changes of them ranged between 3.58 and 6.40 ${\Delta}E$ units. 3. During 300 hours' accelerated aging, the microhardness of surface was increased by 3.21 - 19.64% in all kinds of composites resin. CONCLUSION: After 300 hours' accelerated aging, SEM images IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony showed little morphological change and their color changes were considered to be clinically acceptable. And there was significant correlation between microhardness changes and color changes of composites (P < .05).

• 구강회복응용과학지
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• 제24권3호
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• pp.231-242
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• 2008

본 연구의 목적은 전부 도재관 시스템에서 코어-비니어 결합계면에서의 결합 강도를 평가하는데 있다. 본 연구에서 사용되어진 전부 도재관 시스템은 IPS Empress2 with IPS Eris, IPS e.max Press with IPS e.max Ceram과 IPS e.max ZirCAD with IPS e.max Ceram이다. 제조사의 지시에 따라 코어(N=36, N=12/system, 직경: 10mm, 두께: 3mm)를 제작하였고 초음파 세척을 시행하였다. 특별히 제작된 스테인리스 스틸 몰드를 이용하여 코어 상부에 비니어(직경: 3mm, 두께: 2mm)를 축성한 후 소성하였다. 소성 후, 초음파 세척을 시행하고 아크릴릭 레진에 매몰하였다. 제작된 시편은 $37^{\circ}C$의 증류수에 1주일간 보관하였다. 만능시험기(Z020, Zwick, Germany)로 시편의 전단결합강도를 측정하였고, 하중이 코어-비니어 계면에 가능한 가깝게 가해지도록 시편을 위치시키고, 파절이 일어날 때까지 1.00mm/min의 crosshead speed로 하중을 가하였다. 측정된 각 군의 평균전단결합강도($MPa{\pm}SD$)에 대한 통계적 유의성을 검증하기 위해 일원 분산분석을 시행하였으며, 사후검정은 Tukey test를 이용하였다(p=0.05). 또한 파절된 시편을 주사전자현미경(JSM-6360,JEOL, Japan)으로 파절양상을 관찰하였다. 파절양상은 코어 내에서의 응집성 파절, 비니어 내에서의 응집성 파절, 혼합형 파절 혹은 접착성 파절로 분류하였다. 코어와 비니어 계면에서의 평균전단결합강도($MPa{\pm}SD$)는 IPS-e.max Press가 $32.85{\pm}6.75MPa$, IPS Empress 2가 $29.30{\pm}6.51MPa$, IPS e.max ZirCAD가 $28.10{\pm}4.28MPa$로 나타났다. 통계적 분석 결과 각 시스템 간에서 유의한 차이가 없었다(P>0.05). 어떠한 시스템에서도 접착성 파절은 관찰되지 않았다. IPS Empress 2와 IPS e.max Press에서는 코어와 비니어 내에서의 응집성 파절이 관찰되었으며, IPS e.max ZirCAD에서는 혼합형 파절과 비니어 내에서의 응집성 파절이 관찰되었다.

• 대한치과보철학회지
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• 제35권2호
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• pp.357-364
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• 1997

IPS-empress system is one of widely used all ceramic system. The purpose of this study was to determine the pressing accuracy of reused IPS%Empress ingot. 10 specimens were made using new ingot first, and using the rests of the specimen the another group of specimens were made next. finally, the third group of specimens were made with same procedure mentioned above. The results obtained in this study were as follows ; 1. The pressing accuracy of the first group of specimen was 96.1%, that of the second group was 95.4%, and that of the third group was 95.4%. There was no statistical significance among them, that is, the reuse of the IPS-Empress ingot did not influence on the pressing accuracy. 2. the common site of the defect in pressed ingot was central area at the margin opposite of sprue hole.

• 대한치과보철학회지
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• 제35권2호
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• pp.344-356
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• 1997

The purpose of this study was to evaluate the long term tooth-brushing effect on the color change of specially treated IPS Empress porcelain surface. Staining techique with blue stain and liquid was used. The surfaces of the specimen were treated with 5% and 10% Hydrofluoric acid, 50mm and 250mm alumina sandblast, and then blue stain and liquid were used for external stain. After 29,200, 58,400, 87,600, 116,200 brushing strokes (equivalent to 2, 4, 6, 8 years each), color changes of the stained layer were measured with spectrophotometer(CM-3500d, MINOLTA, Tolkyo, Japan). The result of this study was obtained as follows : 1. The color changes were great after 29,200 tooth brushing strokes in every group, but from 29,200 strokes to 116,800 strokes, there were no significant color changes in each group. (p>0.05) 2. The greastest color changes were observed in 5% HF treated group and the least color changes were observed in $50{\mu}m$ aluminar sandblast treated group in every stroke (p<0.05), but no statistical difference between groups compared with control group (p>0.05). According to these results, pretreatment of I.P.S. Empress porcelain with alumina sandblast improved the color stability It is thought that about 8 year-tooth brushing strokes does not change the color of IPS Empress porcelain significantly on this condition, but long term follow-up will be needed.

• 대한치과보철학회지
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• 제38권5호
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• pp.575-582
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• 2000

This investigation was designed to determine whether heat-pressing and/or simulated heat treatments affected the flexure strength and the microstructure of the lithium disilicate glass-ceramic in the IPS Empress 2 system. Four groups of the specimens were prepared as follows: group 1 - as-received material, group 2 - heat-pressed material; group 3 - heat-pressed and simulated initial heat-treated material; group 4 - heat-pressed and the simulated heat-treated material with full firings for a final restoration. The three-point bending test and the scanning elec-tron microscope (SEM) analysis was conducted for the purpose of this study. The flexure strength of group 2 was significantly higher than that of group 1. However, there were no significant differences in strength among group 2, 3, and 4, and between group 1 and 4. The SEM micrographs of the lithium disilicate glass-ceramic showed the closely packed, multi-directionally interlocking microstructure of numerous lithium disilicate crystals protruding from the glass matrix. The crystals of the heat-pressed materials (group 2, 3, and 4) were a little denser and about two times bigger than those of the as-received material (group 1). This change of microstructure is more obviously exhibited particularly between group 1 and 2. However, there was no a marked difference among group 2, 3, and 4 after the heat-pressing procedure. Although there were significant increase of the strength and some changes of the microstructure after the heat-pressing operation, the combination of the heat-pressing and the simulated subsequent heat treatments did not produce the increase of strength of IPS Empress 2 glass-ceramic.

• 구강회복응용과학지
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• 제18권2호
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• pp.93-99
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• 2002

This study was performed to investigate the color stability of IPS Empress 2 glass-ceramic after heat-pressing and/or heat-treatments. Three types of IPS Empress 2 ingots (shade 100, 300, 500) were tested. For this study, three groups were prepared as follows: group 1 is as-received material, group 2 is heat-pressed material, and group 3 is fully heat -treated material. The color of the specimens was measured with a colorimeter. The data were statistically evaluated with one-way ANOVA and Scheffe's multiple test. The results obtained were as follows: 1. IPS Empress 2 glass-ceramic demonstrated less color stability according as the shade is lighter. Namely, the shade 500 showed the lowest color shifts and the shade 100 showed the greatest color shifts after heat-pressing and heat-treatments. 2. In the cases of shade 100 and 300, the changes of ${\Delta}E^*$ were affected mostly by the changes of $L^*$ and $b^*$. 3. In ${\Delta}E^*$ of the shade 100, there were significant differences among the group 1, 2, and 3 (P<0.001). 4. In ${\Delta}E^*$ of the shade 300, there were significant differences between the group 1 and 2, and the group 1 and 3 (P<0.001). 5. In ${\Delta}E^*$ of the shade 500, there was significant difference only between the group 1 and 3 (P<0.001).

• 대한치과보철학회지
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• 제40권6호
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• pp.545-559
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• 2002

There has been increasing use of IPS Empress $2^{(R)}$ owing to easy fabrication method, high esthetics similar to natural teeth, good marginal accuracy, and sufficient fracture strength. However, in clinical application, although a luting agent and the tooth cementation bonding procedure influence the marginal accuracy and fracture strength restoration, there has been a controversy in the selection of proper luting agent. This study was to measure the marginal fidelites and fracture strength of IPS Empress crowns according to three cement types, Protec $cem^{(R)}$, Variolink $II^{(R)}$ and Panavia $21^{(R)}$. After construction of 12 experimental dies for each group, IPS Empress $2^{(R)}$ crowns were fabricated and luted the metal master die prepartion of the maxillary right premolar. Marginal gaps before cementation and after cementation were measured. Buccal incline on the functional cusp of specimens were loaded until the catastrophic failure and fracture strength was measured. The results of this study were as follows: 1. The range of gap was $34.04{\pm}4.84{\mu}m$ before cementation and $37.88{\pm}5.00{\mu}m$ after cementation, which showed significant difference by paired t-test (p<0.05). The difference in the results from marginal accuracy according to measuring point proved to be not statistically significant by two-way ANOVA test (p>0.05). 2. The difference in the results from marginal accuracy according to three cement types Proved that The Variolink $II^{(R)}$ cement group had the least gap, $35.43{\pm}5.03{\mu}m$, and showed superior marginal accuracy while there existed statistic significance in Protec $cem^{(R)}$ cement group, $39.06{\pm}4.41{\mu}m$ or Panavia $21^{(R)}$ cement group, $39.16{\pm}4.39{\mu}m$ by two-way ANOVA test & multiple range test (p<0.05). 3. The difference in the results from fractures strength testing according to three cement type groups proved to be statistically significant (p<0.05). The Variolink $II^{(R)}$ cement group shows highest fracture strength of $1257.33{\pm}226.77N$, Panavia $21^{(R)}$ cement group has $1098.08{\pm}138.45N$, and Protec $cem^{(R)}$ cement group represents the lowest fracture strength of $926.75{\pm}115.75N$. 4. Three different cement groups of different components showed acceptable marginal fidelity and fracture strength. It is concluded that IPS Empress $2^{(R)}$ crowns luted using Variolink $II^{(R)}$ cement group had stronger fracture strength and smaller marginal gap than the other cement groups. Although Variolink $II^{(R)}$ resin cement seemed acceptable to clinical applications in IPS Empress $2^{(R)}$ system, the IPS Empress $2^{(R)}$ system still requires long-term research due to the lack of data in clinical applications.

• 대한치과보철학회지
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• 제38권5호
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• pp.606-617
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• 2000

The purpose of this study was to measure the marginal fidelities and the fracture strength of IPS Empress $2^{(R)}\;and\;In-Ceram^{(R)}$ ceramic crowns. After constructed of 12 experimental dies for each group, ceramic crowns were fabricated on the metal master dies prepared on the maxillary right premolar Marginal gaps were measured on the specimen between the margin of each crown and finish-ing line of the metal master die by using stereo-microscope($SZ-ST^{(R)}$ Olympus, Japan) and all specimens were cemented on the metal master die with Bistite $II^{(R)}$ (Tokuyama soda Co, LTD., Japan) resin cement. Finally marginal gaps were measured again. To measure of the fracture strength, buccal incline on the functional cusp of specimens were loaded until the catastrophic failure occurred by using the AGS-1000 $D^{(R)}$(Shimadzu, Japan). The result of marginal fidelities and fracture strength were statistically analyzed with the SPSS version 8.0 programs. The results of this study were as follows : 1. No significant difference was found in the mean marginal fidelities and fracture strength between the IPS Empress $2^{(R)}\;and\;In-Ceram^{(R)}$. 2. In comparison of marginal fidelities between before and after cementation, there was significant difference(P<0.05). The IPS Empress 2 system was shown in this study that had good marginal fidelities and fracture strength compared to In-Ceram ceramics. Although this system was acceptable to clinical applications, the system still has to be considered long-term researches about marginal fidelities and fracture strength due to the lack of data about the clinical researches.

• 대한치과보철학회지
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• 제40권5호
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• pp.441-450
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• 2002

The purpose of this study was compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the lower second premolar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement. The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (1284 N). Crowns of 1.5mm depth and $8^{\circ}$ inclination had the lowest strength (951 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.