• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.376-384
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• 2009

Purpose: The purpose of this study was to evaluate the response of osteoblast-like cells to Ca-P coated surface obtained via Ion beam-assisted deposition (IBAD) method and Sol-Gel process on anodized surface by cellular proliferation and differentiation. Material and methods: The surface of a commercially pure titanium (Grade IV) discs with dimension of 10mm diameter and 2 mm thickness was modified by anodic oxidation under a constant voltage of 300 V. The experimental groups were coated with Ca-P by the IBAD method and Sol-Gel process on anodized surface. The surface roughness (Ra) of specimens was measured by optical interferometer and each surface was examined by SEM. To evaluate cell response, MG63 cells were cultured and cell proliferation, ALP activity and the ability of cell differentiation were examined. Also, cell morphology was examined by SEM. The significant of each group was verified by Kruskal-Wallis Test ($\alpha$=.05). Results: The Ra value of Ca-P coated surface by IBAD method was significantly higher than Ca-P coated surface by Sol-gel process (P < .05). The level of cell proliferation and ALP activity was higher in Ca-P coated surface by IBAD method (P<.05). The expression of ALP showed higher level expression in Ca-P coated surface by IBAD method. Cells grown on Ca-P coated surface by IBAD method were uniformly distributed and developed a very close layer. Conclusion: These experiments showed better performances of Ca-P coated surface by IBAD method with respect to Ca-P coated surface by Sol-gel process. Ca-P coated surface by IBAD method appear to give rise more mature osteoblast characteristics and might result in increased bone growth and bone-implant contact.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3731-3739
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• 2009

One-chambered sediment cells with a variety of anodic electrodes were tested for generation of electricity. Material used for anodes was iron, brass, zinc/iron, copper and graphite felt which was used for a common cathode. The estuarine sediment served as supplier of oxidants or electron-producing microbial habitat which evoked electrons via fast metal corrosion reactions or a complicated microbial electron transfer mechanism, respectively. Maximum power density and current density were found to be $6.90\;W/m^2$ (iron/zinc) and $7.76\;A/m^2$ (iron), respectively. Interestingly, copper wrapped with carbon cloth produced better electric performance than copper only, by 60%, possibly because the cloth not only prevented rapid corrosion on the copper surface by some degrees, but also helped growing some electron-emitting microbes on its surface. At anodes oxidation reduction potential(ORP) was kept to be stationary over time except at the very initial period. The pH reduction in the copper and copper/carbon electrodes could be a sign of organic acid production due to a chemical change in the sediment. The simple estimation of interfacial, electrical resistances of electrodes and electrolyte in the sediment cell that a key to the electricity generation should be in how to control corrosion rate or microbial electron transfer activity.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.181-191
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• 2014

In the past, making IR photography needed somewhat complicated process, so its application fields were limited. However, it has become easy to make IR photography with advanced digital technology, so it is expected that the fields of IR photography and existing limit due to difficult making process will be expanded. Therefore, in this study, it is decided that the need of IR standard chart which allows us to manage exposure and tone of IR photography for scientific purpose will increase. Two methods were used to make IR standard chart. First method is to use aluminum. When aluminum has oxide coating through anodic oxidation, it has high durability, corrosion resistance and heat resistance. Also, IR reflectance of aluminum can be controlled in some degree depending on the thickness of oxide coating. Second method is to use pigments. Yellow 10P150 pigment is used for the brightest patch. This pigment is appropriate in this study due to high heat resistance and IR reflectance. Carbon black is used for the darkest patch. Carbon black absorbs much IR, and its color is not faded by any source of light. IR reflectance is adjusted elaborately by mixing two pigments. Finally, 6 patches are selected with consideration for actual IR reflectance of patches. As a result, IR reflectance of random subjects can be known approximately and IR photographs can have appropriate contrast with the IR standard chart.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.4
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• pp.233-238
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• 2012

Purpose: To evaluate the effect of silvernanopartilce treated implants on the bone formation and osseointegration. Methods: Silvernanoparticle was produced using an anodic oxidation method. The size of silvernanoparticle ranged from 3.5 nm to 5.9 nm. To check the effect of the capability of osseointegration of silvernanoparticle coated Implant, 32 implants (16 piece of Implant treated with nanoparticle, and 16 piece of Implant was not treated for control) were placed at both the tibia of 8 New Zealand white rabbits. After 4 weeks, 4 rabbits were sacrificed and the removal torque was measured for comparison of the osseointagration ability. Further, 4 rabbits were sacrificed and sliced samples were made. H&E stain was done for microscopic finding. Results: The removal torque of the experimental group was $102.37{\pm}30.54$ N/cm, and the control group was $73.30{\pm}19.97$ N/cm. It was statistically significant (P<0.001). Microscopic finding also shows extinguish results in silvernanoparticle treated implants. Bone formation rate of the experimental group was 43.94% and the control group was 7.58%. It was observed to be statistically significant (P=0.017). Bone to implant contact rate of the experimental group was 58.09%, and the control group was 19.43%. It was found with statistical significance (P<0.001). Conclusion: The silvernanopartilce treated implant shows a better capability of bone regeneration and osseointegration than the non-treated one. Technology to produce smaller particles would make silver more useful and safer.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.594-605
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• 2006

Statement of problem: Modification of titanium implant surface has potential to ensure clinically favorable performance that several surface modification technologies have been introduced. Among the methods. anodizing method and sol-gel hydroxyapatite coating method have gained much interest due to its roughness and chemical composition of the coating layer, but more of its biocompatibility result is required. Purpose : The purpose of this study was to compare bone-implant interface shear strength of four different surface treated implants as time elapsed. Resonance frequency analysis(RFA) and removal torque measurement methods were employed to measure implant stability at one week and six week after implantation. Material and method: A total of 80 screw-shaped implant [20 machined, 20 resorbable media blasted(RBM), 20 anodized, and 20 anodized+hydroxyapatite sol-gel coated] were prepared, and one of each group was implanted in the tibia of a New Zealand white rabbit that total 20 of them were used. In order to test the implant stability and implant-tissue interface contact changing in the bone bed, each 10 rabbit were sacrificed 1 week and 6 week later while resonance frequency and removal torque were measured. One-way analysis of variance and the Tukey test were used for statistical analysis. Results : The results were as follows. 1. There was no statistically significant difference of implant stability quotients(ISQ) value in RFA between individual groups after 1 week of implantation and 6 weeks(p>0.05). But, there was statistically significant increase of ISQ value in 6 weeks group compared to 1 week group(p<0.05). 2. There was no statistically significant difference in removal torque analysis between individual groups after 1 week of implantation and 6 weeks(p>0.05). but there was statistically significant increase in all 4 groups after 6 weeks compared to 1 week later(p<0.05). 3. There was no statistically significant difference in removal torque analysis between anodized group and HA coating after anodic oxidation 6 weeks later(p>0.05), but significant difference was appeared in both groups compared to RBM group and smooth-machined group(p<0.05). Conclusions : It can be suggested that changes in surface characteristics affect bone reactions. Anodized and anodized+hydroxyapatite sol-gel coating showed significantly improved bone tissue response to implants, but further study on the effect of hydroxyapatite dissolution is needed.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.53-76
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• 1990

The purpose of this study was to evaluate the tensile bond strength of adhesive resins to successively recast Rexillium III and Degudent-U. Recasting was done 4times successively. Specimen $A_1$, were cast by new metal, and $A_2$ by surpus of $A_1$, $A_3$ by surplus of, $A_2$ $A_4$ by surplus of $A_3$, $A_5$ by surplus of $A_4$ plus 50% new metal. The types of surface treatment for resinbonded restoration in this experiment were electrolytic etching by OXY-ETCH(Oxy dental products, Inc., Hillside, New Jersey, U.S,A.), aluminum oxide blasting, anodic oxidation by EZ-OXISOR( Towagiken Co., Kyoto, Japan), electrotinplating by Kura Ace(Kuralay Co., Kyoto, Japan). Three kinds of cementing resin used in this study were Comspan(K.P. Cauil Co, Milford Delaware, U.S.A.), Super Bond C&B(Sun-Medical Co. Ltd., Kyoto,Japan), Panavia EX(Kuralay Co., Ltd., Osaka, Japan). Tensile bond strength was measured by Instron Universal testing machineModel 1125) and all the specimen were observed with SEM(JEOL, JSM-T2000) and mode of bond failure were recorded. The obtained results were as follows : 1. In electrolytic etched group, tensile bond strength was decreassed when recast alloy was used, and tensile bond strength of Compan and panavia EX were not significantly different(P>0.05). 2. In remaining group treated by aluminum oxide blasting, EZ-OXIOR, Kura Ace, tensile bond strength were not changed when recast alloy were used, and tensile bond strength of SuperBond(C&B and Panavia EX were not significantly different(P>0.05). 3. IN SEM evaluation, electrolytic etched group and electrotinplated group exhibited different image when recast alloy was used, and remaining groups treated by aluminum oxide blasting, EZ-OXISOR exhibited the same. 4. IN observation of bond failure, electrolytic etched group exhibited adhesive failure and remaing groups treated by aluminium oxid blasting, EZ-OXISOR, Kura Ace exhibited adhesive and cohesive failure.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.145-149
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• 2007

Electrochemical studies were performed for a single particle of nickel hydroxide for the cathode of Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and electrochemical experiments were performed. As a result of cyclic voltammetry, the oxidation/reduction and oxygen evolution reaction (OER) are clearly separated for a single particle. The total cathodic charge (Qred) is practically constant for the scan rate investigated, indicating that the whole particle has reacted. The total anodic charge(Qox) was larger than that of reduction reaction, and the magnitude of oxygen evolution taking place as a side reaction was enhanced at lower scan rates. As a result of galvanostatic charge and discharge measurement, the discharge capacity of single particle was found to be 250 mAh/g, value being very close to the theoretical capacity (289 mAh/g). The apparent proton diffusion coefficient(Dapp) using potential step method inside the nickel hydroxide was found to range within $3{\sim}4{\times}10^{-9}\;cm^2/s$.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1105-1114
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• 1996

The characteristic and performance of ${\beta}-PbO_2$ layer electrodeposited on ${\alpha}-PbO_2/IrO_2-TiO_2/Ti$ substrate by adding sodium lauryl sulfate and $TiO_2$ powder in lead nitrate solution were investigated by using XRD, SEM, cyclic voltammograms, and macro-elctrolysis. Results of XRD analysis ascertain that ${\beta}-PbO_2$ layers electrodeposited in the presence of sodium lauryl sulfate and $TiO_2$, powder on ${\alpha}-PbO_2/IrO_2-TiO_2/Ti$ substrate have the same tetragonal structure as pure ${\beta}-PbO_2$ layers. The SEM results show that sodium lauryl sulfate tend to diminish crystal size of the deposited layer. The ${\beta}-PbO_2$ electrode electrodeposited in the presence of sodium lauryl sulfate and $TiO_2$ powder gives significantly improved oxygen overvoltage and durability for anodic oxidation in KOH and $HClO_4$ supporting electrolyte. Electrode performance and durability for the evolution of ozone in perchloric acid solution have been investigated by using ${\beta}-PbO_2$ electrodes electrodeposited on Titanium $madras^{(R)}$. It was ascertained that the $PbO_2$ electrode electrodeposited on ${\alpha}-PbO_2/IrO_2-TiO_2/Ti$ $madras^{(R)}$ by adding sodium lauryl sulfate and $TiO_2$ powder in $HClO_4$ supporting electrolyte had the highest current efficiency and durability.

• Journal of the Korean Electrochemical Society
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• v.17 no.3
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• pp.164-171
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• 2014

A highly sensitive and selective non-enzymatic glucose sensor has gained great attention because of simple signal transformation, low-cost, easily handling, and confirming the blood glucose as the representative technology. Until now, glucose sensor has been developed by the immobilization of glucose oxidase (GOx) on the surface of electrodes. However although GOx is quite stable compared with other enzymes, the enzyme-based biosensors are still impacted by various environment factors such as temperature, pH value, humidity, and toxic chemicals. Non-enzymatic sensor for direct detecting glucose is an attractive alternative device to overcome the above drawbacks of enzymatic sensor. Many efforts have been tried for the development of non-enzymatic sensors using various transition metals (Pt, Au, Cu, Ni, etc.), metal alloys (Pt-Pb, Pt-Au, Ni-Pd, etc.), metal oxides, carbon nanotubes and graphene. In this paper, we show that Ni-based nano-particles (NiNPs) exhibit remarkably catalyzing capability for glucose originating from the redox couple of $Ni(OH)_2/NiOOH$ on the surface of ITO electrode in alkaline medium. But, these non-enzymatic sensors are nonselective toward oxidizable species such as ascorbic acid the physiological fluid. So, the anionic polymer was coated on NiNPs electrode preventing the interferences. The oxidation of glucose was highly catalyzed by NiNPs. The catalytically anodic currents were linearly increased in proportion to the glucose concentration over the 0~6.15 mM range at 650 mV versus Ag/AgCl.

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.223-236
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• 2007

This study was attempted to evaluate home-manufactured implants by placing $Stage-1^{(R)}$ Implant (Lifecore, Co., USA) whose surface is treated with REM that has already been varified clinically,$Chaorum^{(R)}$ Implant(Chaorum Co., Korea) whose surface treatment is same as that of Stage-1 Implant and $Atlas^{(R)}$ Implant(Cewellmedi Co., Korea) whose surface is treated with anodic oxidation immediately after the teeth of experimental animals were extracted to compare histological findings among them. Stage-l Implant(diameter: 3.5mm, length: IOmm), Chaorum Implant(diameter: 3.3mm, length: 8.5mm) and Cowell medi Implant(diameter: 4.0mm, length: 8.0mm) were placed into the mandible premolars of 2 adult beagle dogs immediately after their teeth were extracted, and then histological findings were analyzed at 6 weeks. After those implants were inserted directly after their teeth were extracted, the results of periotest were recorded, radiography was done, the subjects went through thorough control for 6 weeks, and then comparison among periotest, radiography and histological finding was made. After comparison of those findings, the values of periotest were satisfactory and bone healing was relatively satisfactory on radiography at 6 weeks. For osseointegration with the bone tissue, Stage-1 was 45.3%, Chaorum 55.3%, and Cowellmedi 52.5%, which was a satisfactory result. Although implant surgery immediately after teeth were extracted involves difficulties among recent implant surgeries, it is being frequently used in that it may reduce surgery hours, the frequency of surgery, and bone loss for patients. This experiment was conducted to evaluate the technological levels of home-manufactured implants that have been remarkably developed in recent years and in conclusion, those implants showed nearly similar result.