• 대한치과기공학회지
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• 제33권1호
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• pp.7-14
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• 2011

Purpose: As the demand and importance of aesthetic aspects in dental treatment become higher, much attention is paid to materials used for dental prostheses. Thus, the marginal fidelity of most-commonly used alloy, IPS - Empress and ZrO2 ceramic is compared. Methods: The alloy core made by casting, IPS - Empress core made by pressing and ZrO2 ceramic core made by CAD/CAM are used to make 10 samples respectively. For each core, three points were measures and the optical microscope (Axio Imager.Alm,Zeiss co., Oberkochen, Germany) was used to observe the cores with a magnification of 100. Results: As for alloy, IPS - Empress and ZrO2 ceramic, the average and deviation of their marginal distance are $29.91\;{\pm}11.93{\mu}m$ for alloy, $33.45\;{\pm}8.61{\mu}m$ for IPS - Empress, and $31.55\;{\pm}9.85{\mu}m$ for ZrO2. The one-way ANOVA test was conducted to compare them. However, there was no statistically significant difference among them. Conclusion: The study on marginal fidelity of alloy, IPS - Empress, and ZrO2 ceramic shows they have no marginal fidelity problem clinically. Therefore, if a system is selected based on the patient's condition or treatment method, there will be no problem.

• 대한치과보철학회지
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• 제41권4호
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• pp.532-537
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• 2003

Statement of the problem : IPS Empress ceramic has been used as one of a esthetic restorative material since it's development, but the broad application of IPS Empress ceramic to clinical prosthodontic field has been limited by its high material cost. Purpose : This study was investigated to evaluate the hardness and fracture toughness after recycling of the IPS Empress ceramic. Material and methods : Reused specimens of IPS Empress were fabricated with repeated pressing. The hardness(Vickers hardness) and fracture toughness of 1st, 2nd and 3rd pressed specimens were measured with Digital Micro Hardness Tester(Model MXT70, Matsuzawa Seiki Co., Ltd, Tokyo, Japan). The obtained data were analyzed using SPSS(Ver 9.5). Result : The mean value of the hardness in the 1st, 2nd and 3rd pressed Empress were $6.23{\pm}0.48MPa,\;5.50{\pm}0.25MPa$, and $5.70{\pm}0.42MPa$. The hardness of the 1st pressing ceramic was higher than those or the 2nd and 3rd pressed ceramics(P<0.05). Hardness of the 3rd pressed ceramic was greater than that of the 2nd pressed ceramic. but there was no significant difference of hardness between those two(P>0.05). The mean value of the fracture toughness was $1.71{\pm}0.16MPam^{1/2}$ in 1st pressed ceramic, $1.78{\pm}0.10MPam^{1/2}$ in 2nd pressed and $1.73{\pm}0.14MPam^{1/2}$ in 3rd pressed IPS ceramic. Fracture toughness of the 2nd pressed ceramic was the highest and that of the 1st pressed ceramic was the lowest. There was no significant difference of fracture toughness among them(P>0.05). Conclusion : Hardness of the 2nd and 3rd pressed IPS Empress ceramics were lesser than that of 1st pressed IPS Empress ceramic(P<0.05), but there was no significant changes of fracture toughness among them(P>0.05).

• 대한치과보철학회지
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• 제47권1호
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• pp.21-28
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• 2009

연구목적: 2종의 열가압 도재 (e.max Press, Empress Esthetic)와 법랑질 간의 마모양상을 알아보기 위하여 장석계 도재 및 제 3형 금합금과 비교, 관찰하였다. 연구 재료 및 방법: 열가압 도재 e.max Press, Empress Esthetic 및 금속도재관 제작용 장석계 도재 Cermaco 3, 제 3형 금합금으로 원반형 시편을 제작하고, 상대 마모재로는 발거된 건전한 소구치의 교두를 이용하여 Pin-on-disk tribometer 상에서 마모시험 하였다. 법랑질의 마모량은 마모 전후 치아 시편의 무게 변화를 측정하여 부피로 환산하였고, 도재 및 금합금 시편의 평균 표면 조도와 마모트랙 깊이를 표면조도기로, 마모트랙 폭을 주사전자현미경으로 측정하여 마모 양상을 비교하였다. 결과: 1. 법랑질의 마모량은 Ceramco 3군에서 가장 크고 Empress Esthetic군, e.max Press군, 금합금군 순으로 작았으며, Ceramco 3군과 Empress Esthetic군 사이와, Empress Esthetic군, e.max Press군 및 금합금군 사이에는 유의한 차이가 없었다 (P>.05). 2. 마모시험 후 도재 시편의 평균 표면 조도는 Ceramco 3군, Empress Esthetic군, e.max Press군 순으로 작았으며, Empress Esthetic군과 Ceramco 3군 사이에는 유의한 차이가 없었다 (P>.05). 3. 마모트랙의 깊이는 모든 군 사이에 유의한 차이는 없었고 (P>.05), 마모트랙의 폭은 법랑질 마모량 순서와 동일하게 Ceramco 3군, Empress Esthetic군, e.max Press군, 금합금군 순으로 작았으며, e.max Press군과 Empress Esthetic군 사이 및 Empress Esthetic군과 Ceramco 3군 사이에 유의한 차이는 없었다 (P>.05). 결론: 열가압 도재는 장석계 도재보다 법랑질을 더 마모시키지는 않았다.

• 대한치과보철학회지
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• 제36권3호
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• pp.524-529
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• 1998

The purpose of this study was to investigate the possibility on recycling of IPS-Empress ceramic for the wide use of IPS-Empress ceramic in prosthodontic treatment. The frexure strength of first pressed, second pressed, and third pressed IPS-Empress ceramic were measured and compared. There was no ststistical difference among three groups, and the result of this study implied the recycled IPS-Empress ceramic has enough frexure strength for clinical use.

• 대한치과보철학회지
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• 제37권6호
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• pp.776-781
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• 1999

The purpose of this study was to investigate the possibility on recycling of IPS Empress ceramic for the wide use of esthetically pleased IPS-Empress ceramic in clinical prosthodontic treatment. The specimens were made of first, second, and third pressed IPS Empress ceramic and were immersed in 0.05% methylene blue solution for 24hours. The amount of color change before and after stain-ning was measured with colorimeter(Model Tc-6Fx, Denshoku Co., Tokyo, Japan). The change of ${\Delta}E$ in first pressed ceramic was 18.33 and those in second and third pressed ceramics were 19.33 and 19.93 respectively. Although there was statistical difference among them, the differences were minute and acceptable. From the results of this study, the possibility of recycling of IPS Empress ceramic could be suggested.

• 대한치과보철학회지
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• 제41권1호
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• pp.71-80
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• 2003

Development of new ceramic and esthetic need of patient increased the use of ceramic restorations. The purpose of this study was to confirm the possibility of recycling for IPS Empress2 which has a lot of advantages in esthetics. 1st, 2nd and 3rd pressed disc-shaped($10{\times}1.5mm$) IPS Empress 2 specimens were made with IPS Empress ingot(shade 200, Ivoclar, Liechtenstein) and pressing furnace(IPS Empress EP 500, Ivoclar, Liechtenstein). Flexure strength was measured with universal testing machine(Zwick 145641, Zwick, Germany), and color change and staining resistance of specimens were evaluated with colorimeter (Model TC-6FX, Tokyo Denshoku Co., Japan). The followings were drawn from this study : 1. Flexure strength of the 1st, the 2nd, and the 3rd pressed specimens showed 236.78 MPa. 247.16MPa, and 220.72MPa, respectively. Flexure strength of the 2nd pressed specimens was higher than others, but there's no statistical difference between them. 2. The color difference between the 1st and the 2nd pressed specimens was 3.25, and that between the 1st and the 3rd pressed specimens was 3.63(P<0.05). 3. The color change after staining of the 1st, the 2nd. and the 3rd pressed specimens were 1.43, 2.64, and 1.45, respectively. In this study, reused IPS Empress 2 specimens showed insignificant change of flexure strength and stain resistance, but they showed some color change according to reuse. From this results, the limited possibility of reuse for IPS Empress 2 could be considered.

• 대한치과보철학회지
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• 제41권5호
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• pp.596-605
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• 2003

Statement of problem : IPS Empress2 system was developed and used in prosthodontic treatment, but the cost of ingot is expensive for wide application. Purpose : This study was to investigate the possibility on recycling of IPS Empress 2 ceramic for wide application of IPS Empress 2 ceramic in prosthodontic treatment. Material and Method : 1st, 2nd and 3rd pressed disc-shaped($10{\times}1.5mm$) IPS Empress 2 specimens were made with IPS Empress ingot(200, Ivoclar, Liechtenstein) and pressing furnace(IPS Empress EP 500, Ivoclar, Liechtenstein). Vicker's surface hardness and fracture toughness, acid resistance, and pressing accuracy of IPS Empress 2 ceramic were measured and analyzed. Surface hardness was measured by microhardness tester(MTX 70. Matsuzawa, Japan), before and after surface treatment with 0.5% hydrofluoric acid and carbonic acid(Coca cola) for evaluation of acid resistance. Results : The surface hardness of 1st pressed specimen was the higher(5.11 GPa) than those of 2nd pressed(4.89 GPa) and 3rd pressed specimen(4.86 GPa), and the fracture toughness of 1st pressed ($1.58MPam^{1/2}$) and 2nd pressed specimen($1.51MPam^{1/2}$) were higher than that of 3rd pressed specimen($1.39MPam^{1/2}$). The changes of surface hardness of 1st, 2nd, and 3rd pressed specimens after treatment with fluoric acid were 0.17, 0.06, 0.05 (GPa) respectively, and those of 1st, 2nd, and 3rd pressed specimens after treatment with carbonic acid were 0.07, 0.00, 0.05(MPa) respectively. The pressing accuracy of 1st,2nd and 3rd specimen were 77.22%, 85.681%, and 75.05%. The pressing accuracy of 2nd pressed specimen was higher than that of the 3rd specimen. Conclusion : The changes of physical properties according to recycling of IPS Empress 2 from this study were insignificant. Therefore the possibility of recycling of IPS Empress 2 can be suggested from the results.

• 대한치과보철학회지
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• 제39권6호
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• pp.599-610
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• 2001

Due to an increasing interest in esthetics and concerns about toxic and allergic reactions to certain alloys, patients and dentists have been looking for metal-free tooth-colored restorations. Recent improvement in technology of new all-ceramic materials and composite materials has broadened the options for esthetic single crown restorations. The aim of this investigation was to study the fracture strength of the metal-free posterior single crowns fabricated using two recently introduced systems, Empress 2 ceramic and Targis-Vectris. Forty premolar-shaped stainless steel dies with the 1mm-wide circumferential shoulder were prepared. Ten cylindrical crowns having a diameter of 8.0mm and total height of 7.5mm were fabricated for each crown system respectively(PFM, Empress staining technique, Empress 2 layering technique, and Targis- Vectris). The crowns were filled with cement and placed on the stainless steel dies with firm finger pressure. The crowns were then stored in distilled water at room temperature for 24 hours before testing. The crowns were tested for fracture strength in an Instron universal testing machine (Instron 6022). With a crosshead speed of 1mm/min the center of the occlusal surface of the crown was loaded using a 4-mm-diameter stainless steel ball until fracture occurred. The fracture surfaces of the crowns were gold coated and examined using scanning electron microscopy(Jeol JSM-840 Joel Ltd., Akishima, Tokyo, Japan). Within the parameters of this study the following conclusions were drawn: 1. The mean fracture strength for PFM crowns was 5829(${\pm}906$)N; for Empress staining technique the fracture strength was 1697(${\pm}604$)N; for Empress 2 Layering technique the fracture strength was 1781N(${\pm}400$)N, and the fracture strength for Targis- Vectris was 3093(${\pm}475$)N. 2. The fracture strength of the PFM crowns was significantly higher than that of the Empress 2 and the Targis-Vectris crowns (P<0.05). 3. The fracture strength of the Targis-Vectris crowns was significantly higher than that of the Empress 2 crowns (P<0.05). 4. No statistical difference was found when Empress staining technique was compared with Empress 2 layering technique. 5. The SEM image of fracture surface of Empress 2 crown showed a very dense microstructure of the lithium disilicate crystals and the SEM image of fracture surface of Targis-Vectris crown showed indentations of Vectris and some fibers tom off from Vectris.

• 대한치과보철학회지
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• 제33권4호
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• pp.611-633
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• 1995

The pupose of this study was to compare the fracture strength of five kinds of all-ceramic crowns(Vintage, Dicor Empress-staining, Empress-layering, In-Ceram) luted with glass ionomer cerment and composite resin cement and to evaluate the effect of cements on the fracture stregth of all ceramic crowns. Five groups of twelve uniform sized all-ceramic crown specimens were fabricated. Six specimens of each group were cemented with glass ionomer cement(Fuji G.I. Cement) and the remaining six specimens of each group were etched, silane-treated, and cemented with composite resin cement(Bistite resin cement). The crowns were stored in water$(37^{\circ}C)$ for 1 day prior to loading in an Instron, using a steel ball(diameter 4mm) at a crosshead speed of 0.5mm/min. The crowns were angled $30^{\circ}$, so the steel ball contacted with the crowns 2mm lingual from the mid-incisal edge. The results obtained were summarized as follows ; 1. With G.I. cement, mean fracture load(Kg) Were : Intage : $18.33{\pm}1.47$ ; Empress-staining : $23.92{\pm}6.67$ ; Dicor : $24.0{\pm}5.81$ ; Empress-layering : $26.92{\pm}2.80$ ; In-Ceram : $51.58{\pm}6.87$ ; ANOVA revealed a significant difference existed(p<0.05) between the group A(Vintage, Dicor, Empress-staining, Empress-layering) and group B(In-Ceram). 2. With Resin cement, mean fracture load(Kg) were : Intage : $22.75{\pm}4.97$ ; Dicor : $42.75{\pm}7.07$ ; Empress-staining : $44.08{\pm}7.99$ ; Empresslayering : $50.42{\pm}5.43$ ; In-Ceram : $52.58{\pm}6.51$ ; ANOVA revealed a significatnt difference existed(p<0.05) between the group A(Vintage) and B(Dicor, Empress-staining Empress-alyering, In-Ceram). 3. Resin cement significantly increased the fracture strength of the all-ceramic crowns for Dicor(156%), Empress-staining(185%), Empress-alyering(187%)(p<0.05); but did not increase the fracture strength of Vintage(128%) and In-Ceram(101%)(p>0.05). 4. Majority of the all-ceramic crowns show a wedge fracture extending through proximal surfaces to an apex, usually apical third(with G.I. cement) or middle third(with Resin cement) of the facial surface.

• 구강회복응용과학지
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• 제22권3호
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• pp.243-250
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• 2006

Due to high esthetic demands from patients, we are driven to fabricate natural-looking(form and color) restorations. In the past decade, the glass-ceramic in dentistry has been used as a material with variable crystals that affects the appearance, characteristics, and mechanical properties of metal-free fixed restoration. The conventional IPS Empress glass-ceramic is a heat-pressed, leucite reinforced material using the "lost wax" principle. This glass-ceramic has been successfully used for esthetic restorations such as all-ceramic crowns, inlays/onlays, and veneers for about 15 years. This article presents that the form and surface texture of clinical crown are duplicated by IPS-Empress system using "lost-wax technique".