• 대한치과보철학회지
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• 제39권2호
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• pp.171-183
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• 2001

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 upper first molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and were cemented with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a 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 $8^{\circ}$ inclination was the highest (1393N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength (1015N) 2. There were no significant differences of the fracture strength according to occlusal depth and axial inclination. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth. 4. There was positive correlation between the fracture strength and the fracture surface area of crowns.

• 대한치과보철학회지
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• 제37권1호
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• pp.127-133
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• 1999

The purpose of this study was to 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 upper first premolar. After 10 metal dies were made fir each group, the IPS Empress ceramic crowns were fabricated and each crown was cemented on each metal die with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a universal testing machine was used to measure the fracture strength. The results were : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (630N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength(378N). There were no significant differences of the fracture strength by axial inclination in same occlusal depth group. 2. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.

• 대한치과보철학회지
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• 제40권6호
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• pp.572-576
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• 2002

This investigation was designed to estimate the biaxial flexure strength and fracture toughness of lithium disilicate glass-ceramics of IPS Empress 2 system pressed with as-received ingots and their sprue buttons. Two groups of the lithium disilicate glass-ceramics were prepared as follows: group 1 is ingot-pressed group; group 2 is sprue button-pressed group. A ball-on-three-ball test was used to determine biaxial flexure strength (BFS) of disks in wet environment. Scanning electron microscopy(SEM) analysis was conducted to observe the microstructure of the ceramics. Unpaired t-test showed that there were no differences in the mean biaxial Hem strength (BFS) and KIC values between group 1 and 2 (p > 0.05). Two groups showed similar values in the KIC and the strength at 5% failure probability. The SEM micrographs of the IPS Empress 2 glass-ceramic showed a closely packed, multi-directionally interlocking pattern of numerous lithium disilicate crystals protruding from the glass matrix. The lithium orthophosphate crystals could not be observed on the fracture surface etched. There was no a marked difference of the microstructure between group 1 and 2. Although there were no tests including color stability, casting accuracy, etc., the results of this study implied that we could reuse the sprue button of the pressed lithium disilicate glass-ceramic of IPS Empress 2 system.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 1996년도 추계학술대회
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• pp.60-60
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• 1996

• 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.

• 대한치과기공학회지
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• 제45권3호
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• pp.81-86
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• 2023

Purpose: This study aimed to observe the effect of laminate veneer on patient's teeth based on the manufacturing of laminate veneer restorations, which are produced by fabricating a ceramic cast body using IPS Empress, a pressure casting method and then forming the veneer by layering. Subsequently, we assessed the potential of its clinical application. Methods: This study discusses and preserves various treatment plans, such as diagnostic wax-up and treatment room diagnosis, for patients who visit the hospital to improve the appearance of teeth due to diastema of maxillary teeth, inexperienced resin filling, lack of esthetics, and external teeth. A ceramic cast body is constructed using IPS Empress, which is an effective and aesthetic restoration pressure casting method to restore the veneer with a laminate made by layering. Results: Compared with the preoperative state, the frontal view of the patient after the final restoration showed the formation of a natural smile line; the space between the central and lateral incisors was filled in synchronously with the adjacent teeth. In addition, the emergence profile is maintained by reducing the over-contour as much as possible. Conclusion: The patient's quality of life is improved by providing them with a satisfactory natural smile.

• 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.