• Journal of Conservation Science
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• v.25 no.4
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• pp.451-464
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• 2009

To do conservation for ceramics, sometimes it needs to clean the ceramics chemically to remove stains on the ceramics, which should be performed with caution. This study will provide quantitative data about the extraction characteristics of major elements from ceramics through the soaking test to evaluate the stability of ceramic cleaning agents. As soft textured pottery(fired at $700^{\circ}C$) had high absorption, it showed higher extraction characteristics in short soaking time. Especially the strong acid among chemical cleaning agents caused the expoliation and the color change on the surface of soft textured pottery. But these color change had no effect on the physical characteristics of soft textured pottery. The hard textured pottery(fired at $1,000^{\circ}C$) is relatively stable in the cleaning agent because it is ascertained the extraction of that was not enough and also it had little chromatic and physical change by strong acid. Porcelains(Celadon, Whiteware and Puncheong ware) was safer than the soft textured pottery due to their low extraction. But it should take precautions to clean the porcelains with lots of cracklewares such like Puncheong ware chemically in connection with the extraction characteristics and their cracklewares.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.2
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• pp.157-170
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• 2007

Purpose: This investigation was designed to determine the translucency and color stability of various core ceramics for all-ceramic restoration using the CIE $L^*a^*b^*$ system. Material and Methods: IPS e.max Press ceramic(Ivoclar-Vivadent, Liechtenstein), $LAVA^{TM}$ All Ceramic(3M-Espe, Germany), Cercon Smart Ceramic(Dentsply, Germany), and Z-match Ceramic(DentAim, Korea) were used for this study. For the specimens of zirconia oxide ceramics, the as-sintered cylindrical blanks($11.0{\times}25.0mm$) were machined into the shape of a disk(0.4, 0.8, 1.5 mm in thickness, 10 mm in diameters) with a diamond grind machine. The IPS e.max Press specimens ($0.8{\times}10mm$) were fabricated using the "lost wax" technique. CIE $L^*a^*b^*$ coordinates and light transmission were recorded for each specimen with a spectrophotometer(CM-2600d, Minolta, Japan). Color differences were calculated using the equation, ${\Delta}E^*ab=[({\Delta}L^*)2+({\Delta}a^*)2+({\Delta}b^*)2]1/2$. Results: The results were obtained as follows: 1. The most translucent group was IPS e.max Press ceramic that is a glass-ceramic, and $Lava^{TM}$ and Z-match ceramic were more translucent than Cercon Smart ceramic in zirconia ceramic group. 2. In the all groups, there was no significant translucent change after 6 times heat-treatments required to make a final restoration. 3. Colored zirconia was showed more yellowish and dark than uncolored zirconia. 4. After heat-pressing, IPS e.max Press ceramic was showed high ${\Delta}E^*ab$ value(4.1 of eM1, 6.8 of eM2) that means to be more whiter than before heat-pressing. However, there was no color change after additive heat treatments for final restoration. 5. In the colored zirconia groups, there was no significant color change after some heat-treatments required to make a final restoration.

• Journal of Conservation Science
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• v.25 no.3
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• pp.293-298
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• 2009

We fabricated the gap-filling material for antic-ceramics restoration which were made up polyvinyl butyral (butvar) base and silane system additive in iso-propyl solvent. This was made hardness control possible that user want. And it have very strong adhesion and shear strength properties and is shown the best properties for pigment filling, anti-contractibility, coloring as like epoxy system materials. Particularly, the yellowing and ir-reversibility problem in Epoxy restoration material were finally steadiness. So, there is guarantee in the eternity and stabilization of restoration for antic-celamics. And in order to show the reversible state of the restoration, we successfully dissolve this polyvinyl butyral gap-filling materials in solvent after perfect restoring the Punchong plate from sam-chun temple site subsequently.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1495-1497
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• 1996

In this study, Object restoration of ultrasonic transducer fabricated with porous piezoelectric ceramics using Modified SCL(Simple Competitive Learning) neural networks are presented. Using the acquired object data $16{\times}16$ pixels, Modified SCL neural networks using the $16{\times}16$ low resolution image was used for object restoration of $32{\times}32$ high resolution image. The experimental results show that the ultrasonic transducer fabricated with porous piezoelectric ceramics could be applied for sonar system.

• 보존과학연구
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• s.32
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• pp.61-74
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• 2011

This study examines the removal effects of solvents which were applied on three adhesives and three filling materials for ceramics. The chosen materials are Cemedine C, Loctite$^{(R)}$ 401$^{TM}$, Araldite Rapid Type, plaster of paris, CDKI 520A+B, Araldit$^{(R)}$ SV427-2+HV427-1. For the first examination, each different materials were soaked into different solvents, and then the soften level were compared by compressive pressure. The result of the first exam showed that Cemedine C was dissolved easily in acetone. Furthermore Araldite, CDK and SV427 were soften efficiently by Dichloromethan, Tetrahydrofuran and DMX(Dichloromethan+Methanol+Xylene). However, Loctite and plaster were not able to make sample for the first test. Therefore, the second test carried on only. The second examination, chosen effective solvents from the first test were applied with two different methods; soaking and saturated atmosphere. Almost every sample could removed by soaking method in ten minutes, and saturated atmosphere method needs 24 hours for the safety.

• Journal of Conservation Science
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• v.31 no.4
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• pp.373-386
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• 2015

This study identified degradation properties by temperature stress with Araldite$^{(R)}$ AY103-1/HY956 used for ceramics. Tensile and compressive strength of durability increased for 6,480 hours at temperature of $34{\sim}45^{\circ}C$. In stability of external stress and temperature, compressive strength is superior to tensile strength, it requires conservation plans considering strength properties and stress of restoration materials. The tensile shear strength of adhesion properties decreased for 4,320 hours at temperature of $40{\sim}60^{\circ}C$. In ceramics with porosity, environments under isothermal-isohumidity are important because interfacial properties of adherend are concerned with performance variation. Glossiness decreased for 6,480 hours at temperature of $34{\sim}45^{\circ}C$ and color difference increased. Gloss stability was superior and color stability was weak, which requires improvement of optical properties. In artifacts on display in museums, there is concern about temperature rise on restoration materials by lighting therefore, it needs to minimize change in physical properties by exposure environments.

• Journal of Conservation Science
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• v.26 no.2
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• pp.133-142
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• 2010

This paper focused on desalination method for the underwater archaeological ceramics. The desalination method applied in this study takes additional conditions such as the amount of desalting water, temperature, and agitation conditions and compares the effects of desalt process. The result of efficiency rate appears that the twenty-times of the object weight of desalting water is more effective than that of ten-times one, but shows less economic compared to the cost. In addition, the research shows that the efficiency rate has been improved around 20 to 30 %, yet such improvement is not taken into account as an effective result considering the risk of damage from the physical and chemical impact and the consumption of energy in applying additional method.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.159-168
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• 2007

Statement of problem: Literature showed different results on the durability of bonded ceramic restoration. Purpose: The purpose of this article is to review the effect of surface treatment of ceramics in resin-ceramic bond to get predictable results. Material and method: PubMed data base was utilized to search the articles which were written in English and published in 1986 and 2006. Some electronic published articles which are forthcoming to publish in paper were also included for this review. This review article focused on the effect of acid etching and silane application on the silica based ceramics. The durability of resin-ceramic bonding, the methodology for bond strength test and resin bonding to alumina or zirconia based ceramics were compared in brief at the end of the review. Results and Conclusion: the effect of silane application can be influenced by the contaminations of saliva or solutions. Micromechanical retention by acid etching as well as silane application plays an important role in initial and durable bond strength between resin and ceramic. The use of phosphate modified resin cement following tribochemical silica coating and silane application produced best bond strength for alumina or zirconia based ceramics.

• The Journal of Advanced Prosthodontics
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• v.11 no.4
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• pp.215-222
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• 2019

PURPOSE. To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution. MATERIALS AND METHODS. 88 ceramic discs ($1.0mm{\times}10.0mm$) were manufactured - 44 nano-fluorapatite layering ceramics (IPS e.max Ceram. Group C) and 44 pressed lithium disilicate ceramic discs (IPS e. max Press - Group P). Each group was divided into 4 subgroups according to surface treatments: (G) Glaze, (S) Shofu polishing system (Shofu Inc.), (E) Edenta AG polishing System, (KG) $30-{\mu}m$ diamond granulation tip. Surface roughness (Ra) and color change (${\Delta}E$) measurings after the surface treatments were performed, before and 12 days after the immersion in coffee solution. A samples' qualitative analysis was conducted with a scanning electron microscopy (SEM). Data were statistically-treated with one-way-ANOVA and Duncan's tests, apart from paired t-test and Pearson's correlation test (${\alpha}=5%$). RESULTS. The decrescent order, both for surface roughness (Ra) and ${\Delta}E$ for both ceramics were: KG > E > S > G (P<.05). With exception for PG and CG subgroups, which did not present statistical difference between them, all other pressed ceramics subgroups presented smaller Ra values and greater ${\Delta}E$ values than the layering ceramics subgroups (P<.05). CONCLUSION. Although mechanical polishing systems presented intermediate Ra values, their colors were considered clinically acceptable. There is a strong correlation between the surface roughness and the color change of tested ceramics.

• Journal of Conservation Science
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• v.19
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• pp.31-42
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• 2006

There are many materials used in restoring missing parts of pottery and ceramics and they are used according to the each quality of materials. In our research we tried to find the new repair materials to solve many problems exposed in the existing repair materials. As a result, we made new repair materials that we properly put oven bake clays into repair epoxy putty which is being used as oven bake clays for a long time. Fortunately, through testing yellowing, vickers hardness, coloring and heating temperature, We could get an idea that new repair materials would be the best materials in the efficiency of restoration, yellowing, and coloring.