• 한국재료학회지
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• 제16권3호
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• pp.157-162
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• 2006

Pressable ceramics have many applications in the field of dental industry because of their excellent esthetic, compressive strength, chemical durability. Despite these attractive characteristics, they have not been widely used since they are very brittle and extremly sensitive to porcelain. In this study, the fabrication of pressable dental porcelain ($SiO_2-Al_2O_3-K_2O-Na_2O$) as a function of contents of $Al_2O_3,\;BaO\;and\;ZrO_2$ were investigated. And then compressive strength, Vickers hardness, density and thermal expansion coefficient (TEC) tests have been carried out to evaluate properties of pressable dental porcelain fabricated. The property of pressable dental porcelain fabricated by adding of 15%$Al_2O_3$ and 2%BaO contents was closely approximated to that of natural tooth.

• 대한치과기공학회지
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• 제34권1호
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• pp.1-9
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• 2012

Purpose: The purpose of this study was to investigate the transmittance differences of pressable ceramic core due to thickness within the visible light spectrum. Methods: 36 specimens were divided into 2 groups (0.6mm, 0.8mm) which have each 3 specimens. The size of specimens was 10mm high and 10mm wide. The transmittance of specimens are measured by spectrophotometer Model Cary 500 that can measure infrared-ray, visible wave and ultraviolet-ray. Results: The results shows that there was no significant difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. Conclusion: The individual's color perception is personal and there are numerous factors that influence on it. In general, human eye can perceive the color of thing only within visible light spectrum but in this experiment through spectrophotometer there was no big difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. To sum up, The most important factors were a layed porcelain structure and its thickness rather than core thickness in the porcelain crown. Also, When making all ceramic core with dead pulp (nervous treatment tooth) when used as a restorative esthetic think is more efficient to improve.

• 대한치과보철학회지
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• 제41권3호
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• pp.379-386
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• 2003

Statement of problem. Resin cements are widely used in adhesive dentistry specially on all ceramic restorations. It is needed to find out adequate bonding strength between different porcelain surface treatments, commercially available porcelains, and different resin cement systems. Purpose. The purpose of this study was to evaluate shear bond strength of resin cements bonded to porcelains in three different modalities; 5 different porcelain surface treatments, 3 different resin cement systems and 3 different commercially available pressable porcelains. Material and Method. This study consisted of 3 parts. Part I examined the effect of five different surface treatments on the pressable porcelain. Fifty discs (5 mm in diameter and 3 mm in height) of Authentic porcelain were randomly divided into 5 groups (n = 10). The specimens were sanded with 320 grit SiC paper followed by 600 grit SiC paper. The specimens were treated as follow: Group 1-Sandblasting (aluminum oxide) only, Group 2 - sandblasting/ silane, Group 3 - sandblasting/ acid etching/ silane, Group 4 - acid etching only, Group 5 - acid etching/ silane. Part II examined the shear bond strength of 3 different resin cement systems (Duolink, Variolink II, Rely X ARC) on acid etching/ silane treated Authentic pressable porcelain. Part 3 examined the shear bond strength of Duolink resin cement on 3 different pressable porcelains (Authentic, Empress I, Finesse). All cemented specimens were stored in distilled water for 2 hours and tested with Ultradent shear bond strength test jig under Universal Instron machine until fracture. An analysis of variance(ANOVA) test was used to evaluate differences in shear bond strength. Result. The shear bond strength test resulted in the following: (1) Acid etched porcelains recorded greater shear bond strength values to the sandblasted porcelains. (2) Silane treated porcelains recorded greater shear bond strength values to non-silane treated porcelains. (3) There was no significant difference between sandblasting/ acid etching/ silane treated and acid etching/ silane treated porcelains. However those values were much higher than other three groups. (4) The shear bond strength with Variolink II was lower than the value of Duolink or Rely X ARC. (5) The shear bond strength of Finesse was lower than the value of Authentic or Empress I.

• 대한심미치과학회지
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• 제10권1호
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• pp.72-78
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• 2001

To maintain the strength obtained with metal ceramic restorations, excellent gradient of translucency, wear resistance in the same range as enamel and good marginal integrity, all ceramics have been developed with many advantages in recent years. Authentic (Ceramay, Germany) is a type of low fusing, leucite-reinforced pressable ceramic that allows both the laying technique and the staining technique or the combination of the two. Two-phase glass ceramic will allow achieving unmatched esthetics even with the simplest laying or staining technique. The ingots and laying porcelain come in Vita shades. Case selection has to be the most crucial thing to achieve optimal esthetics, and cooperation with technician has to be emphasized to satisfy patient's highest esthetic demands.

• 한국세라믹학회지
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• 제41권2호
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• pp.143-150
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• 2004

본 연구에서는 치아 수복에 사용되는 상용 글라스 세라믹들을 디스크 모양으로 열가압 성형하여 ball-on-3-bal에 의한 이축강도와 압입시험에 의한 파괴인성을 측정하였다. 시편들로부터 XRD, SEM, TEM을 이용하여 결정상과 미세구조를 분석하였다. 글라스 세라믹내의 결정들은 균열의 진행에 대하여 효과적인 저지를 하지 못하였으나 높은 결정화도가 기계적 성질의 향상에 기여하는 것으로 판단된다. Lithium disilicate결정의 글라스 세라믹은 상대적으로 결정함량이 낮은 leucite 세라믹에 비하여 유의하게 높은 이축강도와 파괴인성을 나타내어 치과용 글라스 세라믹으로서 높은 신뢰성이 기대된다.

• 대한심미치과학회지
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• 제10권2호
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• pp.15-20
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• 2001

The spaced dentition is a common clinical finding. The careful analysis of clinically spaced dentition is a necessity for effective treatment planning. Spaced dentition often exists in the presence of intact teeth. Therefore, special care should be taken in order to obtain the most successful esthetic effect and to prevent overtreatment as well. The aesthetic restorative dental treatment using the porcelain laminate veneers is getting more popular than the complex orthodontic treatment, and prosthetic solutions that require sacrifice of sound tooth structure. The physical strength of porcelain laminate veneers is not as good as porcelain fused metal crowns, and more researches are needed in the field of bonding between composite cement and porcelain laminate veneer. However, the esthetic results from this unprepared porcelain laminate veneers were satisfactory with Authentic (Ceramay, Germany) pressable ceramic technique and resin cement (Rely X Veneer, 3M). This article deals with 2 cases of unprepared porcelain laminate veneers on anterior teeth.

• 대한심미치과학회지
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• 제11권1호
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• pp.11-15
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• 2002

The black triangle is a common clinical finding in aged people with gingival recessions. Among other prosthetic treatment molalities such as composite resin filling and laminate venners, the all ceramic restoration procedure can lead to most successful result. With improved bonding strength and ceramic properties, the tooth preparation design for all-ceramic crown can be modified to minimize the reduction of sound tooth structure without loosing properties of conventional preparation design. Case selection is an important factor in acheiving succesful prosthesis. In this case report, the leucite reinforced pressable ceramic, $Authentic^{TM}$ [Ceramay, Germany] was used to fabricate the prosthesis.

• 구강회복응용과학지
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• 제16권1호
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• pp.13-25
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• 2000

Optimal Pressable Ceramic is one of the all-ceramic restorations with a shaded translucent pressed core and layering porcelains. The purpose of this study was to evaluate the marginal fidelity according to margin types and measurement sites, and to evaluate fracture strength according to margin types. Twenty seven OPC crowns made according to 3 types of cervical finishing lines were used in this study. Marginal gaps were measured before and after cementation. A Steromicroscope(SZ-ST(R), Olympus, Japan) was used to measure the space between the margin of OPC crown and the finishing line of metal model. Marginal gaps were measured at the labial, mesial, lingual and distal site, which were demonstrated in advance. Fracture strength testing was carried out using an Instron(Model M100EC, Mecmesin, England) at a cross head speed of 5 mm/min. All crowns were loaded until catastrophic failures occurred. The result were as follow: 1. In comparison according to variable margin before cementation, the marginal gap were increased in chamfer margin($47.50{\pm}18.39{\mu}m$), $120^{\circ}$shoulder margin ($55.21{\pm}14.4{\mu}m$) and $90^{\circ}$shoulder margin($71.18{\pm}13.30{\mu}m$) in ascending order, and there were significant differences between chamfer margin and $90^{\circ}$shoulder margin, $120^{\circ}$shoulder margin and between $120^{\circ}$shoulder margin and $90^{\circ}$shoulder margin respectively(p<0.05). 2. In comparison according to variable margin after cementation, the gap discrepancies were increased in chamfer margin($60.78{\pm}30.37{\mu}m$), $120^{\circ}$shoulder margin($66.67{\pm}11.18{\mu}m$) and $90^{\circ}$shoulder margin($85.78{\pm}17.23{\mu}m$) in ascending order, but there was significant difference only between chamfer margin and $90^{\circ}$shoulder margin(p<0.05). 3. Labio-lingual points showed a better marginal fidelity than that of proximal point(p<0.05). 4. Chamfer margin($48.76{\pm}8.45kgf$) showed higher fracture strength than $120^{\circ}$ shoulder margin($40.57{\pm}7.90kgf$) and $90^{\circ}$ shoulder margin(32.7.90kgf) (p<0.05), but there was significant difference only between chamfer margin and $90^{\circ}$ shoulder margin(p<0.05).

• 대한치과보철학회지
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• 제36권2호
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• pp.273-292
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• 1998

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 $0.6{\times}1.6mm$ 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 $70{\mu}m$ 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 $31.42{\pm}16.52{\mu}m$ in conventional In-Ceram, $55.45{\pm}27.90{\mu}m$ in copy-milled In-Ceram using Celay system, $44.36{\pm}24.59{\mu}m$ in IPS Empress, $47.21{\pm}20.42{\mu}m$ in OPC. 2. In the marginal fit of conventional In-Ceraw 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 kinds of all-ceramic crowns was clinically acceptable.

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.347-353
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• 2018

PURPOSE. The purpose of this study was to evaluate the marginal discrepancy of heat-pressed ceramic veneers manufactured using a CAD/CAM system. MATERIALS AND METHODS. The ceramic veneers for the abutment of a maxillary left central incisor were designed using a CAD/CAM software program. Ten veneers using a microstereolithography apparatus (AM group), ten veneers using a five-axis milling machine (SM group), and ten veneers using a traditional free-hand wax technique (TW group) were prepared according to the respective manufacturing method. The ceramic veneers were also fabricated using a heat-press technique, and a silicone replica was used to measure their marginal discrepancy. The marginal discrepancies were measured using a digital microscope (${\times}160$ magnification). The data were analyzed using a nonparametric Kruskal-Wallis H test. Finally, post-hoc comparisons were conducted using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The $mean{\pm}SD$ of the total marginal discrepancy was $99.68{\pm}28.01{\mu}m$ for the AM group, $76.60{\pm}28.76{\mu}m$ for the SM group, and $83.08{\pm}39.74{\mu}m$ for the TW group. There were significant differences in the total marginal discrepancies of the ceramic veneers (P<.05). CONCLUSION. The SM group showed a better fit than the AM and TW groups. However, all values were within the clinical tolerance. Therefore, CAD/CAM manufacturing methods can replace the traditional free-hand wax technique.