• The Korean Journal of Ceramics
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• v.4 no.4
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• pp.372-376
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• 1998

Using calcium-phosphate-powder targets with the Ca/P ratios of 1.0-1.67, hydroxyapatite ($Ca_{10}(PO_4)_6(OH)_2$, HAp) thin films with 4-7㎛ thickness were prepared on titanium metal plates by r.f. magnetron sputtering, followed an annealing at $200^{\circ}C$ for 24 hr under a high water vapor pressure using an autoclave. All the specimens were systematically characterized by XRD, FT-IR, SEM and EDS analyses. The post-annealed films were confirmed to be a nonstoichiometric oxyhydroxyapatite by XRD and FT-IR measurements.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.33-33
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• 1993

• The Journal of the Korean dental association
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• v.53 no.3
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• pp.195-200
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• 2015

Cementation is the last procedure and an important factor to access successful fixed prosthodontic treatment. Even though there are many kinds of luting materials in dental field, the resin cements are popularly used in now. Metals, polymers and ceramics are used as a material of fixed dental prosthesis. The bonding mechanisms between teeth and fixed restorations are composed of mechanical and chemical mechanism. In dentistry, we are relying on mechanical bonding, but we tried to get chemical bonding and many ways are introduced. So, we have to approach luting procedure differently by the materials of prosthesis for clinical success. In this article, let us think the proper cementation ways according to each prosthesis material.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.781-792
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• 1997

This study was peformed to evaluate the dynamic fatigue characteristics of the dental ceramics for all-ceramic crown. A feldspathic porcelain of VMK68. glass ceramic of IPS-Empress, and glass infiltrated alumina ceramic of In-Ceram were used. Disc specimens were prepared to the final dimensions of 12 mm in diameter and 1 mm in thickness. The biaxial flexure test was conducted using a ball-on-three-ball method. 240 specimens were tested in $37^{\circ}C$ water by testing 20 samples at each of four loading rates:0.05, 0.2, 1, and 5mm/min. 60 specimens were tested in a moisture-free environment by testing 20 samples at 5mm/min. The inert strength of VMK68 was 80.25MPa, and the fatigue parameters were n=29.1, ${\sigma}_{fo}=52.90MPa$. The inert strength of IPS-Empress was 104.76MPa, and the fatigue parameters were n=32.46, ${\sigma}_{fo}=67.52MPa$. The inert strength of In-Ceram was 429.33MPa, and the fatigue parameters were n=31.46, ${\sigma}_{fo}=258.36MPa$. 10-year failure stresses of VMK68, IPS-Empress, and In-Ceram were 20.3MPa, 24.8MPa, and 93.6MPa, respectively. Failure strength and fatigue life showed the highest value in In-Ceram, and then, IPS-Empress and VMK68.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.33-41
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• 2002

In dental prosthetics, the application of metal-ceramic restorations has steadily increased since their introduction. This is due to excellent esthetics in combination with high mechanical stability. In order to optimum bond strength between metal and ceramics, controlled oxidation of metal substructure is essential factor. Beryllium containing and beryllium free Ni-Cr alloys for metal-ceramic restorations were evaluated for the metal-ceramic bond strength by changing heat treatment for oxide formation. A mechanical three-point bending test was employed to evaluate the interfacial bond strength of metal-ceramic. In each metal, plate type specimens were used for mechanical three-point bending test. With Ni-Cr alloys for metal ceramics, mechanical three-point bending test showed that double degassing was more available preheat treatment method than another. It was found that beryllium containing Ni-Cr alloys are more effective than beryllium-free for metal-ceramic bond strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2150-2156
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• 2009

The effects of MgO and coloring agents on the physical properties and color of zirconia based ceramics with glass frit were studied. The addition of MgO was effective on the coloring of zirconia-20wt% glass frit system. Major factor on the coloring was turned out to be sintering temperature. Coloring agents was turned out to be more effective than the addition of MgO on the coloring of zirconia base ceramics. Specimen without glass frit showed drastic change in color, while specimen with 20wt% glass frit revealed a limited change in color. This means that the addition of glass frit suppresses the coloring of zirconia based ceramics. The effect of sintering temperature on coloring revealed little change in color.

• Journal of Technologic Dentistry
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• v.41 no.3
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• pp.177-185
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• 2019

Purpose: This study was to investigate the effect of three different surface treatments on the shear bond strength of lithium disilicate ceramics to enamel. Methods: Totally 60 lithium disilicate ceramic disc specimens were fabricated with IPS e.max press (Ivoclar Vivadent, Schaan, Liechtenstein) and Mazic Claro (Vericom, Korea). 30 specimens in each lithium disilicate ceramic were assigned to 3 groups of the each following surface treatment: 1) $50{\mu}m$ airborne particle abrasion+silane, 2) 9.5% hydroflouric acid etching (HF)+silane, 3) $50{\mu}m$ airborne particle abrasion+9.5% HF+silane. Lithium disilicate ceramic surfaces after surface treatments were AFM examined. The shear bond strength was measured in a universal testing machine at 0.5mm/min crosshead speed. All data were analyzed using a two-way ANOVA and Tukey's test(${\alpha}=0.05$). Results: The mean surface roughness of lithium disilicate ceramics ranged from $0.178{\mu}m$ to $0.441{\mu}m$. The mean shear bond strengths ranged from $23.81{\pm}2.78MPa$ to $33.99{\pm}4.85MPa$. Conclusion: 1. Mazic Claro showed higher shear bond strength than IPS e.max press at 3 different surface treatments, and no statistically significant was observed. 2. The shear bond strength of IPS e.max press was strongly enhanced as surface treated with $50{\mu}m$ airborne particle abrasion and 9.5% hydroflouric acid etching. And there was no statistical significance at the shear bond strength of Mazic Claro with surface treatments.

• Korean Journal of Materials Research
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• v.16 no.3
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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.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.161-170
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• 2002

The Purpose of this study was to investigate the chemically improvement of metal-ceramics bond strength in the course of recasting Ni-Cr metal composite system with 10wt.%, 20wt.% and 30wt.% aluminum respectively. We have tested the bond strength, micro-structure, chemical composition of each metal composites and metal- ceramic bond interfaces by 3-point bending strength tester, SEM and EDS. We have made the conclusions through this study as follow: 1. The most suitable amount of aluminum to the Ni-Cr metal composite recasting is 20wt. % for improving metal-ceramics bond strength with debonding strength value of 49.54 kgf/mm2. 2. The aluminum must be changed to small spread alumina like phases and second aluminum-metal composites phases in the morphology of Ni-Cr metal composite system by adding during it's casting. These second phases have inclined functional oxide phases mixed with metal elements and they must take roll to improvement of metal-ceramics bond strength. 3. In the case of 30wt.% aluminum appended to Ni-Cr metal composite system, an excess of second inclined functional oxide phases produce cracks and spalling of them apart from it's base material. It must be a important factor of reduction of metal-ceramics bond strength.

• The Journal of Advanced Prosthodontics
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• v.8 no.6
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• pp.417-422
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• 2016

PURPOSE. The purposes of this study were to evaluate the staining resistance of CAD/CAM resin-ceramics polished with different techniques and to determine the effectiveness of the polishing techniques on resin-ceramics, comparing it with that of a glazed glass-ceramic. MATERIALS AND METHODS. Four different CAD/CAM ceramics (feldspathic ceramic: C-CEREC Blocs, (SIRONA) and three resin-ceramics: L-Lava Ultimate, (3M ESPE), E-Enamic, (VITA) and CS-CeraSmart, (GC)) and one light cure composite resin: ME-Clearfil Majesty Esthetic (Kuraray) were used. Only C samples were glazed (gl). Other restorations were divided into four groups according to the polishing technique: nonpolished control group (c), a group polished with light cure liquid polish (Biscover LV BISCO) (bb), a group polished with ceramic polishing kit (Diapol, EVE) (cd), and a group polished with composite polishing kit (Clearfil Twist Dia, Kuraray) (kc). Glazed C samples and the polished samples were further divided into four subgroups and immersed into different solutions: distilled water, tea, coffee, and fermented black carrot juice. Eight samples ($8{\times}8{\times}1mm$) were prepared for each subgroup. According to CIELab system, four color measurements were made: before immersion, immersion after 1 day, after 1 week, and after 1 month. Data were analyzed with repeated measures of ANOVA (${\alpha}=.05$). RESULTS. The highest staining resistance was found in gl samples. There was no difference among gl, kc and cd (P>.05). Staining resistance of gl was significantly higher than that of bb (P<.05). Staining resistances of E and CS were significantly higher than those of L and ME (P<.05). CONCLUSION. Ceramic and composite polishing kits can be used for resin ceramics as a counterpart of glazing procedure used for full ceramic materials. Liquid polish has limited indications for resin ceramics.