• 대한치과기공학회지
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• 제33권1호
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• pp.37-45
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• 2011

Purpose: Heat pressed ceramics, used for all ceramic restorations, have the additional advantage of being technically less change through using of the lost-wax technique. Conceptually, combining the ceramic with the clinically proven reinforcing ability of a metal framework would be advantageous; however, cause of mismatching of fusion between ceramics and metal frameworks which from differences of casting temperature and coefficient of thermal expansion, pressed ceramics could not be used with a metal framework. The purpose of this study was to compare shear bond strength of press-to metal ceramic to porcelain fused non precious metal and feldspatic porcelain fused non precious metal. Methods: The 30 metal specimens were casted in a porcelain fused non precious metal nickel-chromium alloy. They were divided into 3 groups by surface treatment and applied ceramic: $125{\mu}m$ aluminium oxide sandblasting and veneered feldspatic porcelain (group FP), $125{\mu}m$ aluminium oxide sandblasting and had press-to-metal ceramic applied (group PC), porcelain bonder (gold bonder) fused on surface of metal specimens and had press-to-metal ceramic applied (group PCG). In each group 10 metal specimens were used. The press-to-metal ceramic applied 20 specimens had ash-free wax pattern applied, the metal-wax complexes invested, and were pressed with heat press ceramic. All specimens were subjected to shear bond strength test at a crosshead speed of 1.0 mm/min. Results: The results of measured in Mean SD and data were analyzed by one-way AVOVA (p= .05) and Tukey HSD test (p= .05).: group FP $16.090{\pm}1.841$ MPa, group PC $12.620{\pm}1.8256$ MPa, group PCG $10.920{\pm}0.9283$, significant differences between all groups (p < .05). Significant differences were found in each between group FP and group PC, group FP and group PCG (p < .05). Conclusion: The shear bond strength of press-to-metal ceramic to porcelain fused non precious metal was described higher in unused gold bonder group than used gold bonder groups.

• 대한치과기공학회지
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• 제39권2호
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• pp.101-107
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• 2017

Purpose: The purpose of this study was to compare the shear bond strength of the metal-heat pressed glass ceramic bilayer structure. Methods: Metal framework specimens were prepared and surface is spreaded opaque(IPS InLine system opaque, IvoclarVivadent, Liechtenstein). There were 10 specimens for each bilayer dental ceramic group. The first group was porcelain fused metal, Press on metal IPS Inline press group, and press on metal HASS prototype group. Specimens measured for the shear bond strength on Schwickerath test by Instron universal testing machine(Instron3345, Instron Corp., USA). Mean average bond strength values of each specimen group were analyzed using a one-way ANOVA analysis of variance Saphiro-wilk's test. Statistical analysis were performed using IBM SPSS 23.0(IBM Co., Armonk, USA) Results: $RMS{\pm}SD$ The highest mean average HASS POM showed a bond strength value ($47.55{\pm}12.80Mpa$). The lowest mean average values Porcelain fused metal ($33.30{\pm}2.00Mpa$). Independent t-test was conduct to analysis the significant difference (p<0.05) (Table 3). Conclusion: Three kinds of Metal/ glass bilayer dental ceramics bond strength were clinical acceptability. Especially, as lithium disilicate containing represents higher bond strength.

• 대한치과보철학회지
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• 제52권2호
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• pp.90-96
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• 2014

연구 목적: 이 연구의 목적은 열가압성형기법이 금속도재관의 치경부 변연적합도에 미치는 영향을 확인하는 것이다. 연구 재료 및 방법: 실험에 앞서, 4개의 금속 주모형을 형성하였다. 각 모형은 각각chamfer, heavy chamfer, shoulder with bevel, shoulder (collarless)변연을 형성하였다. 각 변연당 10개씩의 금관을 제작하여, 총 40개를 제작하였다. Coping 단계에서, 그리고 금속도재관 완성 단계에서 주모형과 금관 사이의 변연간극은 100배율의 광학현미경 관찰을 통하여 측정되었다. Data분석은 paired t-test along with one-way ANOVA와 Duncan multiple comparison test를 이용하여 이루어졌다. 결과: 변연간극의 평균과 표준편차를 분석한 결과, 금속 코핑과 그 후 완성된 금속도재관, 모든 경우에서 변연부 간격은 임상적 허용범위 안에 있었다. Chamfer 변연 실험군의 경우 Heavy chamfer 변연 실험군에 비하여 금속도재관 완성 후 변연부 간격의 유의한 증가가 있었다. 그리고Shoulder 변연 실험군에서 도재로 처리된 변연이 Chamfer와 Shoulder변연 실험군의 금속변연에 비하여 변연부 간격이 유의하게 작게 나타났다. 결론: 열가압성형기법을 통하여 제작한 금속도재수복물의 변연적합도는 전통적인 방법으로 제작한 금속도재수복물의 변연적합도와 유의한 차이점이 없었다. 제작과정의 효율성으로, 열가압성형기법은 임상에서의 효과적인 사용법으로 고려될 수 있다.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.241-244
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• 2014

Fabricating a crown to retrofit an existing abutment tooth for a partial removable dental prosthesis (PRDP) is one of the most time-consuming and labor-intensive clinical procedures. In particular, when the patient is concerned with esthetic aspects of restoration, the task of fabricating becomes more daunting. Many techniques for the fabrication of all-metallic or metal-ceramic crowns have been discussed in the literature. This article was aimed to describe a simple fabrication method in which a retrofitting crown was fabricated for a precise fit using a ceramic-pressed-to-metal system.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.723-731
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• 2022

Functionally graded materials (FGMs) have been spotlighted as an advanced composite material, accordingly the intensive studies have focused on FGMs to examine their mechanical behaviors. Among them is thermal buckling which has been a challenging subject, because its behavior is connected directly to the safety of structural system. In this context, this paper presents the numerical analysis of thermal buckling of metal-ceramic functionally graded (FG) plates. For an accurate and effective buckling analysis, a new numerical method is developed by making use of (1,1,0) hierarchical model and 2-D natural element method (NEM). Based on 3-D elasticity theory, the displacement field is expressed by a product of 1-D assumed thickness monomials and 2-D in-plane functions which are approximated by NEM. The numerical method is compared with the reference solutions through the benchmark test, from which its numerical accuracy has been verified. Using the developed numerical method, the critical buckling temperatures of metal-ceramic FG plates are parametrically investigated with respect to the major design parameters.

• 대한치과기공학회지
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• 제27권1호
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• pp.89-95
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• 2005

In the manufacture of ceramo-metal crown, difference of fracture strength according to the metal depth has been known to be an important influence on enough intensity and internal stress to endure an occlusion-pressure as well as aesthetics of rehabilitating similar colour such as natural teeth. Depth of ceramic material could be determined by that of metal in three groups: first case of thin depth, second case of thick depth, and third case of constant depth. For the enhancement of the fracture strength between metal and ceramic materials and aesthetic satisfaction, a study on the bonding force, fracture strength, and aesthetics have been required more. In this study, therefore metal coping were made in three groups of A, B and C by using both ceramic powder of Norithe and metal of Columbium, which have been used primarily in the market. A group was made in $0.2mm\times10mm\times10mm$, B group was made in $0.4mm\times10mm\times10mm$, and, C group was made in $0.8mm\times10mm\times10mm$, respectively. The number of metal coping in each group was 10, and total sample numbers used in this study were 30 metal copings. After these metal coping tissue were in the process of build-up in 1.5mm constant depth of porcelain, firing, and glazing, the fracture strength about each metal coping tissue was investigated using oil press. It was found that the average values of durable occlusion pressure for separation of ceramic material in the porcelain fused to metal crown (PFM) in the each group showed the increasing order of A group (30 bar), B group (42 bar), and C group (44 bar), respectively. Proper depth of metal coping in the PFM was considered to be 0.4mm in the B group because this metal size showed higher durable property to the occlusion pressure and better coupling strength in the ceramo-metal crown.

• Steel and Composite Structures
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• 제44권2호
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• pp.171-181
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• 2022

Functionally graded material (FGM) has been spotlighted as an advanced composite material due to its excellent thermo-mechanical performance. And the buckling of FGM resting on elastic foundations has been a challenging subject because its behavior is directly connected to the structural safety. In this context, this paper is concerned with a numerical buckling analysis of metal-ceramic FG plates resting on a two-parameter (Pasternak-type) elastic foundation. The buckling problem is formulated based on the neutral surface and the (1,1,0) hierarchical model, and it is numerically approximated by 2-D natural element method (NEM) which provides a high accuracy even for coarse grid. The derived eigenvalue equations are solved by employing Lanczos and Jacobi algorithms. The numerical results are compared with the reference solutions through the benchmark test, from which the reliability of present numerical method has been verified. Using the developed numerical method, the critical buckling loads of metal-ceramic FG plates are parametrically investigated with respect to the major design parameters.

• Steel and Composite Structures
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• 제21권2호
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• pp.429-442
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• 2016

The aim of this paper is to determine temperature and stress distributions in a ceramic based on Partially Stabilized Zirconia coated steel piston crown by using plasma spraying for improving performance of a marine diesel engine. Effects of coating constituent and thickness on temperature and stress distributions were investigated including comparisons with results from an uncoated piston by means of finite element method namely ANSYS. Temperature developed at the coated surface is significantly higher than that of the uncoated piston. The maximum stress components occur between bond coat and adjacent ceramic layer. Provided that coating thickness is constant as 0.5 mm, when numbers of layers increase, magnitude of the normal stress decrease about 34.1% on the base metal surface according to uncoated piston, but the base metal surface temperature of the steel piston increase about 13.1%.

• 대한치과기공학회지
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• 제34권2호
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• pp.135-143
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• 2012

Purpose: The purpose of this in vitro study was to compare the marginal fit of POM restorations with 3 different thickness of metal coping. Methods: 2.0mm Occlusal reduction, 1.0mm preparation of axial wall with 6degree taper, and chamfer margin was prepared a maxillary first premolar on dentiform. Duplicate prepared die and, make 30 individual dies with Ni-Cr metal. Make 3 groups of 30 press ceramic on Metal crown with different thickness of metal coping; 10 of 0.1mm, 10 of 0.3mm, 10 of 0.5mm thickness metal coping. The marginal fit of the crowns was evaluated 50 points per 1 crown, around the crown margin circumference under a optical microscope at original magnification ${\times}100$. A 1-way analysis of variance (ANOVA) was used to compare data. Results: The mean marginal discrepancy for POM with 0.1mm metal copings was $72.56{\mu}m$, $67.83{\mu}m$ for 0.3mm metal coping POMs, and $72.56{\mu}m$ for 0.5mm metal coping POM. The 1-way ANOVA showed significant difference among 3 groups. Conclusion: The marginal fit of pressed-on-metal (POMs) was best with 0.3mm thickness of metal coping, fallowing by 0.1mm, and 0.5mm in the order.

• Advances in materials Research
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• 제8권4호
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• pp.295-311
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• 2019

In this study, a three-dimensional Finite Element Model has been developed to estimate the size of the weakened zone in a bi-material a ceramic bonded to metal. The calculations results were compared to those obtained using Scanning Electron Microscope (SEM). In the case of elastic-plastic behaviour of the structure, it has been shown that the simulation results are coherent with the experimental findings. This indicates that Finite Element modeling allows an accurate prediction and estimation of the weakening effect of residual stresses on the bonding interface of Alumina. The obtained results show us that the three-dimensional numerical simulation used by the Finite Element Method, allows a good prediction of the weakened zone extent of a ceramic, which is bonded with a metal.