• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.217-222
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• 1998

Coating films of $SiO_2-TiO_2-AgO$ have been prepared on soda-lime-silica slide glasses and single crystal silicon wafer by the sol-gel method using a spin-coating technique. Commercially available tetraethyl orthosilicate, titanium trichloride, and silver-nitrates were used as starting materials. The heat treatment temperature of this coating films was $500^{\circ}C$ properly, obtained from TG-DTA result. The films with thickness of 310 nm were prepared by 5 times coating. In the case of l0 mol% AgO, the film showed a crack-free and smooth surface, but the higher Ago content exhibited the more pin hole and the segregated cluster of AgO. The IR absorbance of the films decreased in the range of 400 nm to 700 nm with the increase of annealing temperature. And the reflectance of the coating films decreased and the color was changed light yellow to white yellow with the increase of Ago content.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.56-61
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• 2009

STATEMENT OF PROBLEM. The success of titanium implants is due to osseointegration or the direct contact of the implant surface and bone without a fibrous connective tissue interface. PURPOSE. The purpose of this study was to evaluate the osteoblast precursor response to titanium-10 tantalum-10 niobium(Ti-Ta-Nb) alloy and its sputtered coating. MATERIAL AND METHODS. Ti-Ta-Nb coatings were sputtered onto the Ti-Ta-Nb disks. Ti6-Al-4V alloy disks were used as controls. An osteoblast precursor cell line, were used to evaluate the cell responses to the 3 groups. Cell attachment was measured using coulter counter and the cell morphology during attachment period was observed using fluorescent microscopy. Cell culture was performed at 4, 8, 12 and 16 days. RESULTS. The sputtered Ti-Ta-Nb coatings consisted of dense nanoscale grains in the range of 30 to 100 nm with alpha-Ti crystal structure. The Ti-Ta-Nb disks and its sputtered nanoscale coatings exhibited greater hydrophilicity and rougher surfaces compared to the Ti-6Al-4V disks. The sputtered nanoscale Ti-Ta-Nb coatings exhibited significantly greater cell attachment compared to Ti-6Al-4V and Ti-Ta-Nb disks. Nanoscale Ti-Ta-Nb coatings exhibited significantly greater ALP specific activity and total protein production compared to the other 2 groups CONCLUSIONS. It was concluded that nanoscale Ti-Ta-Nb coatings enhance cell adhesion. In addition, Ti-Ta-Nb alloy and its nanoscale coatings enhanced osteoblast differentiation, but did not support osteoblast precursor proliferation compared to Ti-6Al-4V. These results indicate that the new developed Ti-Ta-Nb alloy and its nanoscale Ti-Ta-Nb coatings may be useful as an implant material.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.187-193
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• 2005

The photocatalyst $TiO_2$ thin film was made from titanium (IV) isopropoxide, ethanol, and HCl by sol-gel method. The surface observation by SEM showed the sample that was coated 5 times at $500^{\circ}C$ had good properties. The component ratio, in atom% of O : Ti by EDX analysis, of 61 : 39 by spin coating was superior than dip coating. It was found that crystal structure changed from anatase phase to rutile phase as a function of the temperature of thin film fabrication, and this was measured by XRD. The photolysis efficiency of total organic compounds (TOC) by lighting UV beam on $TiO_2$ thin film showed 20%~65% within 1 h, and decreased slowly thereafter.

• Corrosion Science and Technology
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• v.17 no.3
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• pp.91-100
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• 2018

Development of biodegradable implants for treatment of complex bone fractures has recently become one of the priority areas in biomedical materials research. Multifunctional corrosion resistant and bioactive coatings containing hydroxyapatite $Ca_{10}(PO_4)_6(OH)_2$ and magnesium oxide MgO were obtained on Mg-Mn-Ce magnesium alloy by plasma electrolytic oxidation. The phase and elemental composition, morphology, and anticorrosion properties of the coatings were investigated by scanning electron microscopy, energy dispersive spectroscopy, potentiodynamic polarization, and electrochemical impedance spectroscopy. The PEO-layers were post-treated using superdispersed polytetrafluoroethylene powder. The duplex treatment considerably reduced the corrosion rate (>4 orders of magnitude) of the magnesium alloy. The use of composite coatings in inducing bioactivity and controlling the corrosion degradation of resorbable Mg implants are considered promising. We also applied the plasma electrolytic oxidation method for the formation of the composite bioinert coatings on the titanium nickelide surface in order to improve its electrochemical properties and to change the morphological structure. It was shown that formed coatings significantly reduced the quantity of nickel ions released into the organism.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.121-126
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• 2015

In general, the pearlescent pigment is a pigment which was used for optical characteristics like pearl, rainbow and metallic luster. Titanium dioxide coated mica plate developed by DuPont in 1965 is currently being used as a main part of pearlescent pigment for cosmetics. Although the smooth and clear surface substrate laminated with 2 ~ 3 ingredients is thicker than a previous monolayer coated substrate, it has been applied for cosmetics as the optical interference powder to realize stronger shine and brighter interference color than monolayer one. In this study, we developed a new optical interference powder with thinner and higher chroma than a current pearlescent pigment for the strong luster and bright interference color. It was prepared from the manufacturing process, in which the coated titanium dioxide precursor was changed and crystallized by coating and heat treatment process with a half of dividing the coated amount of titanium dioxide. We confirmed the dense coating of titanium dioxide grain with Scanning Electron Microscope and measured superior crystallization degree compared with a monolayer coated pearlescent pigment by X-ray Diffraction. It is concluded that our new pearlescent pigment had higher reflectivity of light and stronger interference color than previous products.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.199-199
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• 2016

Commercially pure titanium (cp-Ti) and Ti alloys (typically Ti-6Al-4V) display excellent corrosion resistance and biocompatibility. Although the chemical composition and topography are considered important, the mechanical properties of the material and the loading conditions in the host have, conventionally. Ti and its alloys are not bioactive. Therefore, they do not chemically bond to the bone, whereas they physically bond with bone tissue. The electrochemical deposition process provides an effective surface for biocompatibility because large surface area can be served to cell proliferation. Electrochemical deposition method is an attractive technique for the deposition of hydroxyapatite (HAp). However, the adhesions of these coatings to the Ti surface needs to be improved for clinical used. Plasma electrolyte oxidation (PEO) enables control in the chemical com position, porous structure, and thickness of the $TiO_2$ layer on Ti surface. In addition, previous studies h ave concluded that the presence of $Ca^{+2}$ and ${PO_4}^{3-}$ ion coating on porous $TiO_2$ surface induced adhesion strength between HAp and Ti surface during electrochemical deposition. Silicon (Si) in particular has been found to be essential for normal bone and cartilage growth and development. Zinc (Zn) plays very important roles in bone formation and immune system regulation, and is also the most abundant trace element in bone. The objective of this work was to study electrochemical characteristcs of Zn and Si coating on Ti-6Al-4V by PEO treatment. The coating process involves two steps: 1) formation of porous $TiO_2$ on Ti-6Al-4V at high potential. A pulsed DC power supply was employed. 2) Electrochemical tests were carried out using potentiodynamic and AC impedance methoeds. The morphology, the chemical composition, and the micro-structure an alysis of the sample were examined using FE-SEM, EDS, and XRD. The enhancements of the HAp forming ability arise from $Si/Zn-TiO_2$ surface, which has formed the reduction of the Si/Zn ions. The promising results successfully demonstrate the immense potential of $Si/Zn-TiO_2$ coatings in dental and biomaterials applications.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.500-510
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• 2008

Statement of problem: Recently researches about WC/C (Tungsten Carbide/Carbon) or TiN (Titanium Nitride) coating on abutment screws are going on. It decreases friction coefficient, resistance against corrosion and withdrawal of physical fragility when the coating is applied to the metal surfaces. It is reported that coated abutment screws improved abrasion, adaptability and detorque force. Purpose: This study is about the effects of coated abutment screws on loosening of screw and for the purpose of solving the loosening phenomenon of abutment screws which is clinical problem. Material and methods: Detorque force and surface changes are compared when 10 times of repeated closing and opening are applied to both uncoated titanium abutment screws (Group A) and coated abutment screws with WC/C (Group B) and TiN (Group C). Each group was made up of 10 abutment screws. Results: 1. Before repeated closing and opening, Somewhat rough surface with regular direction was observed in Group A. Coated granules were observed in group B and group C and overall coated layer appeared in regular and smooth form. 2. Before repeated closing and opening, The coated surface showed bigger and thicker size of coated granules in Group C than Group B. 3. After repeated closing and opening, abrasion and deformation of abutment screw surface was observed in Group A and Group B. Exfoliation phenomenon was observed in Group B. 4. Group A showed biggest range of decrease when the weight changes of abutment screws were measured before and after repeated closing and opening. Group C showed less weight changes than Group B but there was no statistical difference between two groups. 5. Group B and Group C showed higher average detorque force than Group A and there was statistical difference. 6. Group A showed more prominent decrease tendency of average detorque force than Group B and Group C. Conclusion: Coated abutment screws with WC/C or TiN did not show prominent surface changes than uncoated titanium abutment screws even though they were repeatedly used. And they showed excellent resistance against friction and high detorque force. Thus it is considered that adaptation of WC/C or TiN coating on abutment screws will improve the screw loosening problem.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.333-340
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• 2011

Purpose: The aim of this study was to study the effect of hydroxyapatite (HA) coating crystallinity on the proliferation and differentiation of human osteosarcoma cells. Materials and methods: Surface roughness of the titanium disks increased by anodizing treatment and then HA was coated using ion beam-assisted deposition (IBAD). HA coating was crystallized by heat-treated at different temperature ($100^{\circ}C$, $300^{\circ}C$, $500^{\circ}C$, $800^{\circ}C$). According to the temperature, disks were divided into four groups (HA100, HA300, HA500, HA800). With the temperature, crystallinity of the HA coating was different. Anodized disks were used as control group. The physical properties of the disk surface were evaluated by surface roughness tests, XRD tests and SEM. The effect of the crystallinity of HA coating on HOS cells was studied in proliferation and differentiation. HOS cells were cultured on the disks and evaluated after 1, 3, 5, and 7 days. Growth and differentiation kinetics were subsequently investigated by evaluating cell proliferation and alkaline phosphatase activity. Results: Regardless of the heat-treated temperature, there is no difference on the surface roughness. Crystallinity of the HA was appeared in the groups of HA500, HA800. HOS cells proliferation, ALP activity were higher in HA500 and HA800 group than HA100 and HA300. Conclusion: Within the results of this limited study, heat treatment at $500^{\circ}C$ of HA coating produced by IBAD has shown greater effect on proliferation and differentiation of HOS cells. It is considered that further in vivo study will be necessary.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.620-627
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• 2008

STATEMENT OF PROBLEM: A biochemical approach for surface modification has offered an alternative for physicochemical and morphological methods to obtain desirable bone-implant interfaces. PURPOSE: The purpose of the present study was to investigate cell responses to poly (D,L-lactide-co-glycolide) (PLGA)/$1{\alpha}$,25-(OH)$_2D_3$ coating with reference to cellular proliferation and differentiation in vitro. MATERIAL AND METHODS: 96 titanium discs were fabricated and divided into four groups. Group 1 was anodized under 300 V as control. Group 2, 3 and 4 were anodized then coated with 3 ml PLGA/$1{\alpha}$,25-(OH)$_2D_3$ solutions. Amount of the solutions were 2 ul, 20 ul and 200ul respectively. The osteoblast-like Human Osteogenic Sarcoma (HOS) cells were seeded and cultured for 1, 3 and 7 days. MTSbased cell proliferation assay and ALPase activity test were carried out. RESULTS: PLGA nanoparticles were observed as fine, smooth and round and HOS cells attached to the anodized surfaces through strand-like and sheet-like filopodia. After 3 days of culture, the dendritic filopodia were exaggerated and sheet-like cytoplasmic projections covered the coated titanium surfaces. After 3 days of culture, all of the groups showed increased cellular proliferation and the lowest proliferation rate was measured on group 2. Higher amount of incorporated $1{\alpha}$,25-(OH)$_2D_3$ (Group 3 and 4) improved cellular proliferation but the differences were not significant statistically (P > .05). But they increased the rate of ALP activities than the control group at day 3 (P < .05). CONCLUSION: Biodegradable PLGA nanoparticles incorporated with vitamin D metabolite positively affected proliferation and differentiation of cells on the anodized titanium surface.

• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.14-21
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• 2014

PURPOSE. The purpose of this study was to evaluate bone response to anodized titanium implants coated with the extract of black cohosh, Asarum Sieboldii, and pharbitis semen. MATERIALS AND METHODS. Forty anodized titanium implants were prepared as follows: group 1 was for control; group 2 were implants soaked in a solution containing triterpenoids extracted from black cohosh for 24 hours; group 3 were implants soaked in a solution containing extracts of black cohosh and Asarum Sieboldii for 24 hours; group 4 were implants soaked in a solution containing extracts of pharbitis semen for 24 hours. The implants from these groups were randomly and surgically implanted into the tibiae of ten rabbits. After 1, 2, and 4 weeks of healing, the nondecalcified ground sections were subjected to histological observation, and the percentage of bone-to-implant contact (BIC%) was calculated. RESULTS. All groups exhibited good bone healing with the bone tissue in direct contact with the surface of the implant. Group 2 ($52.44{\pm}10.98$, $25.54{\pm}5.56$) showed a significantly greater BIC% compared to that of group 3 ($45.34{\pm}5.00$, $22.24{\pm}2.20$) with respect to the four consecutive threads and total length, respectively. The BIC% of group 1 ($25.22{\pm}6.00$) was significantly greater than that of group 3 ($22.24{\pm}2.20$) only for total length. CONCLUSION. This study did not show any remarkable effects of the extract of black coshosh and the other natural products on osseointegration of anodized titanium implants as coating agents. Further studies about the application method of the natural products on to the surface of implants are required.