ABSTRACT
Objective: To evaluate fracture resistance and survival rate of IPS Empress CAD versus Polished Celtra Duo ceramic laminate veneers. Material and Methods:Thirty-six ceramic laminate veneers were fabricated for maxillary anterior teeth. The patients were divided into two groups according to the material Group 1(control group) fabricated from IPS Empress CAD laminate veneers and group 2 (intervention group) fabricated from Polished Celtra Duo laminate veneers. Standardized the same preparation with butt joint design and chamfer finish line located supra gingival were performed for all the teeth. The fabrication of the veneers was performed using Cad\Cam (Ceramill motion) machine, with software (Exocad). The veneers surfaces were treated and silanated according to the manufacture instruction of each ceramic and enamel surfaces were etched where total etch adhesive protocol was obeyed using BISCO. Follow up sessions were done every two months up to one year for each patient using dental probe and operator vision to evaluate the fracture, survival rate, marginal adaptation, sensitivity and caries. according to USPHS criteria (United States Public Health Service). This was performed by an experienced, blinded investigator. Results: Fracture resistance, marginal adaptation, retention, caries and sensitivity were evaluated according to the criteria of USPHS and we found there is no significant difference as both groups scaled zero score. Conclusion: Both IPS Empress Cad and Polished Celtra Duo laminate veneers revealed successful clinical performance in terms of fracture resistance, marginal adaptation, retention, and sensitivity after one year follow up period (AU)
Objetivo: Avaliar a resistência à fratura e a taxa de sobrevivência de laminados de cerâmica IPS Empress CAD versus Celtra Duo polidos. Material e Métodos: Trinta e seis facetas cerâmicas laminadas foram confeccionadas para dentes anteriores superiores. Os pacientes foram divididos em dois grupos de acordo com o material Grupo 1 (grupo controle) confeccionado com laminados IPS Empress CAD e grupo 2 (grupo intervenção) confeccionado com laminados Celtra Duo polidos. A mesma forma de preparo e acabamento de chanfro localizado supra-gengival padronizados foram realizados para todos os dentes. A confecção das facetas foi realizada em máquina Cad \ Cam (Ceramill motion), com software (Exocad). As superfícies laminadas foram tratadas e silanizadas de acordo com as instruções do fabricante de cada cerâmica e as superfícies de esmalte foram condicionadas seguindo o protocolo adesivo de condicionamento ácido total com BISCO. Sessões de acompanhamento foram realizadas a cada dois meses durante um ano para cada paciente usando sonda exploradora e visão do operador para avaliar a fratura, taxa de sobrevivência, adaptação marginal, sensibilidade e cárie; de acordo com os critérios USPHS (Serviço de Saúde Pública dos Estados Unidos). Isso foi realizado por um investigador experiente e cego. Resultados: a resistência à fratura, adaptação marginal, retenção, cárie e sensibilidade foram avaliadas de acordo com os critérios da USPHS e não encontramos diferença significativa, pois ambos os grupos escalonaram pontuação zero. Conclusão: As facetas laminadas IPS Empress Cad e Celtra Duo polido revelaram desempenho clínico bem-sucedido em termos de resistência à fratura, adaptação marginal, retenção e sensibilidade após um período de acompanhamento de um ano. (AU)
Subject(s)
Humans , Dental Marginal Adaptation , Dental Caries , Dental Veneers , Dentin Sensitivity , Flexural StrengthABSTRACT
PURPOSE: The purpose of this study was to colorimetrically evaluate the masking effect of different opacity of ingots on the final shade of IPS Empress Esthetic(R) laminate veneer restorations using the CIE L*a*b* system. MATERIALS AND METHODS: Six porcelain disks of IPS Empress Esthetic(R) system (translucency: E 01, E 03, E 0C-1, E TC-1, E TC-2, E TC-3) were fabricated with 7 mm in diameter and 0.6 mm in thickness. Six extracted human incisors (shade: A1, A3, A4, B2, B3, C3) were used as the abutment specimens. The incisors were prepared using a diamond wheel and made with a flat labial surface on the middle 1/3. For each combination of different shades of abutments and copings, the change in color was measured with a colorimeter. CIE L*a*b* coordinates were recorded for each specimen. Color differences (DeltaE) were calculated. Descriptive statistical analysis was done. RESULTS: DeltaE values were significantly affected by coping translucency and abutment shade (P<.05). The color differences (DeltaE) of laminate veneers among abutments with A3, B3, C3, and A4 shade were mostly below 2.7 which was within the clinically acceptable range, while color differences between A4 and B2, A3 and B2, and A1 and A4 showed more than 2.7. CONCLUSION: The final color of IPS Empress Esthetic(R) laminate veneers were significantly influenced by translucency of the coping and shade of abutment teeth. The large value difference of abutment teeth limited the masking ability by laminate veneers.
Subject(s)
Humans , Dental Porcelain , Diamond , Incisor , Masks , ToothABSTRACT
PURPOSE: The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the incisal reduction (2.0mm, 2.5mm, 3.0mm) and axial inclination (4degrees., 8.degrees, 12degrees.) of the upper canine. MATERIALS AND METHODS: After 10 metal dies were made for 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 the universal testing machine was used to measure the fracture strength. RESULTS: 1. The fracture strength of the ceramic crown with 3.0mm depth and 12degrees inclination was the highest (839N). Crowns of 2.0mm depth and 12degrees inclination had the lowest strength (559N). 2. There was no significant difference in the fracture strength by axial inclination in the same incisal reduction group. 3. 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 incisal reduction.
Subject(s)
Ceramics , Crowns , Resin CementsABSTRACT
STATEMENT OF PROBLEM: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. PURPOSE: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. MATERIAL AND METHODS: Forty-five sample disks(15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPSEmpress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabricated. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions: (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm); (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE L*a*b* systems and color difference(delta E) was calculated. RESULTS: 100 shade ingot: when ceramic thickness was 1.0mm, delta E value for ceramic post larger than 1 but delta E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only delta E value for metal was larger than 2, and the other samples' delta E value was smaller than 2. For ceramic thickness of 2.0mm, E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, delta E value for ceramic post was smaller than 1 but delta E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the delta E value for metal was larger than 2, and the other samples' delta E value was smaller than 2. For ceramic thickness of 2.0mm, delta E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only delta E value for metal was larger than 2 and the other samples' delta E value was smaller than 2. For ceramic thickness of 1.5mm, delta E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, delta E values for all specimens was smaller than 1. CONCLUSION: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.
Subject(s)
Ceramics , Crowns , Esthetics , Hot Temperature , Masks , Reading , ToothABSTRACT
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 +/-0.48MPa, 5.50+/-0.25MPa, and 5.70+/-0.42MPa. The hardness of the 1st pressing ceramic was higher than those of the 2nd and 3rd pressed ceramics(P0.05). The mean value of the fracture toughness was 1.71+/-0.16MPam1/2 in 1st pressed ceramic, 1.78 +/-0.10MPam1/2 in 2nd pressed, and 1.73+/-0.14MPam1/2 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(P0.05).
ABSTRACT
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 (4degree, 8degree, 12degree) of the lower First Molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. LTD., Japan). The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine(Zwick Z020, Zwick, Germany)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 12degree inclination was the highest (1789 N). Crowns of 1.5 mm depth and 4degree inclination had the lowest strength (1091 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. Size of fragment was affected by the amount of occlusal reduction.
Subject(s)
Ceramics , Crowns , Molar , Resin CementsABSTRACT
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(10x1.5mm) 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.
Subject(s)
Humans , Ceramics , Esthetics , RecyclingABSTRACT
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(10x1.5mm) 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 (1.58 MPam1/2)and 2nd pressed specimen(1.51 MPam1/2) were higher than that of 3rd pressed specimen(1.39 MPam1/2). 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.
Subject(s)
Carbon , Carbonic Acid , Ceramics , Hardness , Hydrofluoric Acid , Prosthodontics , RecyclingABSTRACT
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 degrees, 8 degrees, 12 degrees) 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 degrees inclination was the highest (1284 N).Crowns of 1.5mm depth and 8 degrees inclination had the lowest strength (951N). 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.
Subject(s)
Bicuspid , Ceramics , Crowns , Resin CementsABSTRACT
The purpose of this study was to investigate the effects of desensitizer on shear bond strength of adhesive resin cements for all ceramic crown. For this study,Gluma desensitizer(R)(Heraeus Kulzer, Germany)and MS Coat(R)(Sun medical, Japan)were used as desensitizer,and Bistite II(R) resin cement(Tokuyama, Japan)and VariolinkII(R) resin cement(Ivoclar, Liechtenstein) were used. IPS Empress ceramics were bonded to dentin surfaces after application of desensitizer and shear bond strength of specimens were measured using UTM(Zwick 1456 41, Zwick, Germany)at a crosshead speed of 1mm/min. The obtained results were as follows: 1. The shear bond strength of both resin cements were not affected by Gluma desensitizer(R) containing HEMA. 2. The shear bond strength of Bistite II(R) resin cement was significantly decreased by MS Coat(R). 3. The failure mode in MS Coat(R)-Bistite II(R) group was mainly adhesive type between dentin and resin cement, but that of Gluma desensitizer(R)-Variolink II(R) group was mainly mixed type, combined adhesive failures between dentin and resin cement or porcelain and resin cement.
Subject(s)
Adhesives , Ceramics , Crowns , Dental Porcelain , Dentin , Resin CementsABSTRACT
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 flexure 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.
Subject(s)
Celiac Disease , Ceramics , Glass , Lithium , PhosphatesABSTRACT
Objective: To evaluate the clinical performance of IPS-Empress Ⅱ ceramic crown in a five-year period.Methods:IPS-Empress Ⅱ ceramic crown was applied in 130 teeth treatment of 39 patients. The restorative cases include the single tooth missing, acquired tooth body defect, malformed teeth and discoloration caused by tetracycline, fluoride and the root canal treatment. The 130 teeth were investigated after luting in two weeks, 6, 12 to 60 months respectively. Modified Ryge criteria were used to assess the integrity of restoration, gingival health, color match, marginal adaptation, and sensitivity.Results:More than 96.2% restorations were found to be intact and had excellent marginal adaptation. Little wane existed in one crown at the incisal area. One crown fell with its post caused by failed post adhere. Due to the heavy occlusion force, one of the posterior bridge cracked. Obvious inflammation was found in 3 teeth and only two teeth suffered apicitis. No secondary caries and unsatisfactory color match were found in each follow-up examination. Conclusion:IPS-Empress Ⅱ ceramic crown and bridge is a reliable and ideal choice for the anterior aesthetic restoration.
ABSTRACT
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 glassceramic 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 electron 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 conr bination of the heat-pressing and the simulated subsequent heat treatments did not produce the increase of strength of IPS Empress 2 glass-ceramic.
Subject(s)
Fires , Glass , Hot Temperature , LithiumABSTRACT
STATEMENT OF THE PROBLEM: All-ceramic post-and-core restorations offer a number of advantages compared with systems that use metal build-ups. In certain clinical cases, however, fractures at the joint between the post and core build-up have been reported. PURPOSE: The objective, therefore, is to improve the joint between the post and the core build-up. MATERIAL AND METHODS: Three different methods were used to prepare all-ceramic post-andcore restorations; pressing IPS Empress core build-ups to CosmoPost zirconia posts, cementing IPS Empress core build-ups to CosmoPost zirconia posts and Celay-milling of zirconia blanks. A series of ten restorations was prepared for each of the three methods. The post-and-core complexes were tested to failure with the load applied perpendicular to the post axis. The load and deflection at fracture were recorded. RESULTS: The highest breaking load and highest deflection were recorded for the cementing technique with values of 25.3 N and 394 micrometer, respectively. The corresponding values for the pressed core build-ups and the milled zirconia core build-ups were 22 N and 301 micrometer, and 13 N and 160 micrometer, respectively. All the differences are statistically significant (p=0.05). Regarding the load-dependence of the deflection, the cemented core build-ups again demonstrated the highest value with 15.5 micrometer/N. The difference in the values of 13.6 micrometer/N and 13 micrometer/N recorded for the pressed-on and milled core build-ups, respectively, were statistically insignificant. CONCLUSION: In regard to the high fracture resistance of zirconia post, adhesive cementing the core build-up to the post offers a viable alternative to the conventional pressing technique. The elastic bond between the rigid high-strength zirconia post and the core build-up presents an additional advantage.
Subject(s)
Adhesives , Axis, Cervical Vertebra , JointsABSTRACT
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 (4degree, 8degree, 12degree) of the upper first premolar. After 10 metal dies were made for 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 12degreeinclination was the highest (630N). Crowns of 1.5mm depth and 4degreeinclination 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.
Subject(s)
Bicuspid , Ceramics , Crowns , Resin CementsABSTRACT
The purpose of this study was to evaluate marginal fit of four all-ceramic crown systems 1) conventional In-Ceram, 2) copy-milled In-Ceram using Celay system, 3) IPS Empress, 4) OPC(Optimal Pressable Ceramic). All ceramic crowns were made on epoxy dies. The fabricated crowns were sandblasted, cleaned with ultrasonic cleansing, silanated, and cemented with Bistite composite resin cement. The selected marginal areas of the crowns were the labial, lingual, mesial, and distal surface. Each selected area of surface was 0.6Xl.6mm in dimension. The image of each marginal area was captured to computer files using DT-55 Frame Grabber and light microscope connected CCD camera. The marginal gaps were measured every 70mm using computer image analysis program. The results obtained were summarized as follows : 1. The marginal fit of four all-ceramic crowns were significantly different from each other(p<0.01), and mean marginal fit values obtained were 31.42 +/- 16.52mm in conventional In-Ceram, 55.45 +/- 27.90mm in copy-milled In-Ceram using Celay-system, 44.36 +/- 24.59mm in IPS Empress, 47.21 +/- 20.42mm in OPC. 2. In the marginal fit of conventional In-Cerani and copy-milled In-Ceram crowns using Celay-system there was no significant difference between mesiodistal and buccolingual surface. but in the marginal fit of IPS Empress and OPC crowns, there was significant difference between mesiodistal and buccolingual surface(p <0.01). 3. The marginal fit of four hinds of all-ceramic crowns was clinically acceptable.
Subject(s)
Ceramics , Crowns , Resin Cements , UltrasonicsABSTRACT
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 technique 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, Thkyo, 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 greatest color changes were observed in 5% HF treated group and the least color changes were observed in 50 micrometer aluminar sandblast treated group in every stroke(p0.05). According to these results, pretreatment of I.P.S. Empress porcelain with alumina sandblast improved the color of IPS Empress porcelain significantly on this condition, but long term follow-up will be needed.