• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.67-71
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• 2000

The wear behaviors of ultrahigh molecular weight polyethylene pins against titanium alloy and stainless steel disks moving in two different kinematic motion were investigated by conducting repeat pass rotational sliding and linear reciprocal sliding wear tests. Linear reciprocal motion wore more the polyethylene pin than did repeat pass rotational motion for both disk materials. It means that the repeated directional change of contact stresses generates more wear debris in polyethylene. For the linear reciprocal sliding tests, titanium alloy disks were damaged with some scratches after one million cycles but no surface damage was observed on the polyethylene pins. On the other hand, for the repeat pass rotational sliding tests, all titanium alloy disks were severely abraded on the entire region of sliding track. This phenomenon can be interpreted by that stress fatigue under repeated sliding contact initiated titanium oxide layer wear particles from disk surface, and these hard particles were embedded into polyethylene pin and then they severely abraded the disk surface. From these results it can be concluded that the kinematic motion in pin-on-disk wear tests play a crucial role on the wear behaviors of UHMWPE pins against titanium alloy and stainless steel disks.

• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.299-308
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• 2008

Purpose: The aim of this study was to evaluate adhesion and gene expression of the MC3T3-E1 cells cultured on machined titanium surface (MS) and anodized titanium surface (AS) using MTT test, Scanning electron micrograph and cDNA microarray. Materials and Methods: The MTT test assay was used for examining the proliferation of MC3T3-E1 cells, osteoblast like cells from Rat calvaria, on MS and AS for 24 hours and 48 hours. Cell cultures were incubated for 24 hours to evaluate the influence of the substrate geometry on both surfaces using a Scanning Electron Micrograph (SEM). The cDNA microarray Agilent Rat 22K chip was used to monitor expressions of genes. Results: After 24 hours of adhesion, the cell density on AS was higher than MS (p < 0.05). After 48 hours the cell density on both titanium surfaces were similar (p > 0.05). AS had the irregular, rough and porous surface texture. After 48 hours incubation of the MC3T3-E1 cells, connective tissue growth factor (CTGF) was up-regulated on AS than MS (more than 2 fold) and the insulin-like growth factor 1 receptor was down-regulated (more than 2 fold) on AS than MS. Conclusion: Microarray assay at 48 hours after culturing the cells on both surfaces revealed that osteoinductive molecules appeared more prominent on AS, whereas the adhesion molecules on the biomaterial were higher on MS than AS, which will affect the phenotype of the plated cells depending on the surface morphology.

• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.575-584
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• 2007

The present study was performed to evaluate the effect of citric acid on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, and HA coated surface were utilized. Pure titanium machined surface and HA coated surface were rubbed with pH 1 citric acid for 30s., 45s., 60s., 90s., and 120s. respectively. Then, the specimens were processed for scanning electron microscopic observation. The following results were obtained. 1. The specimens showed a few shallow grooves and ridges in pure titanium machined surface implants. The roughness of surfaces conditioned with pH 1 citric acid was slightly increased. 2. In HA-coated surfaces, round particles were deposited irregularly. The specimens were not significant differences within 45s. But, began to be changed from 60s. The roughness of surfaces was lessened and the surface dissolution was increased relative to the application time. In conclusion, pure titanium machined surface implants and HA coated surface implants can be treated with pH 1 citric acid for peri-implantitis treatment if the detoxification of these surfaces could be evaluated.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.1
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• pp.1-7
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• 2018

Purpose: The purpose of this study is to investigate the effect of the titanium implant soaked in saline after RBM surface treatment on the initial osseointegration by comparing the removal torque and the surface analysis compared to the titanium implant with only RBM surface treatment. Materials and methods: The control group was RBM surface treated implants (RBM), and the test group was implants soaked in saline for 2 weeks after RBM surface treatment (RBM+Sal). The control and test group implants were placed in the left and right tibiae of 10 rabbits, respectively, and at the same time, the insertion torque (ITQ) was measured. After 10 days, the removal torque (RTQ) was measured by exposing the implant site. FE-SEM, EDS, Surface roughness and Raman spectroscopy were performed for the surface analysis of the new implant specimens used in the experiments. Results: There was no significant difference in insertion torque and removal torque between RBM surface treated titanium implants and saline-soaked titanium implants after RBM surface treatment. Conclusion: Saline soaking after RBM surface treatment of titanium implants did not positively affect the initial osseointegration as compared to titanium implants with only RBM surface treatment.

• The Journal of the Korean dental association
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• v.48 no.2
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• pp.106-112
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• 2010

Tissue engineering has been enhanced by advance in biomaterial nature, surface structure and design. In this paper, I report specifically vertically aligned titania ($TiO_2$) nanotube surface structuring for optimization of titanium implants utilizing nanotechnology. The formation, mechanism, characteristics of titania nanotubes are explained and emerging critical role in tissue engineering and regenerative medicine is reviewed. The main focus of this paper is on the unique 3 dimensional tubular shaped nanostructure of titania and its effects on creating epochal impacts on cell behavior. Particularly, I discuss how different cells cultured on titania nanotube are adhered, proliferated, differentiated and showed phenotypic functionality compared to those cultured on flat titanium. As a matter of fact, the presence of titania nanotube surface structuring on titanium for dental applications had an important effect improving the proliferation and mineralization of osteoblasts in vitro, and enhancing the bone bonding strength with rabbit tibia over conventional titanium implants in vivo. The nano-features of titania nanotubular structure are expected to be advantageous in regulating many positive cell and tissue responses for various tissue engineering and regenerative medicine applications.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.243-250
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• 2010

The bonding strength and color reproducibility of titanium-ceramic prosthesis were analyzed the effect according to the surface treatments of titanium and the glazing temperatures of the low fused porcelain. The result of bonding strength compared with respect to the surface treatments was observed that the STB1 group coated by TiN had strongest boding strength and then came the SB1 group used special bonding agent, the SGB1 group coated by gold in that order. The bonding strength by the glazing temperature was indicated that the group with $770^{\circ}C$ of glazing temperature was observed increasing the bonding strength as compared with it of the other group, and the group with $810^{\circ}C$ of glazing temperature was observed to be decreased the bonding strength. Glazing temperature increases, the color by the surface treatment of titanium influenced the color of titanium-ceramic on account of getting higher brightness(${\Delta}L$). As a this result, the SB1 and SGB3 groups was evaluated to has the best color reproducibility.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.245-251
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• 2013

Purpose: This study was conducted to compare in vivo biofilm formation on titanium surface and zirconia surface. Materials and methods: For biofilm formation on titanium and zirconia in oral cavity, after producing oral appliances using acrylic resin and orthodontic wire tailored to 9 subjects, we made titanium and zirconia specimens ($6mm{\times}6mm{\times}2mm$), fixed them on oral appliances and maintained them in oral cavity of test subjects for 24 and 72 hours. Test subjects who have equipped two pairs of specimens maintained oral hygiene not by using toothpaste but only by tooth brushing. After 24 and 72 hours, we removed and observed specimens through scanning electron microscopy (SEM). Results: Biofilm formation showed large deviation depending on individuals. For formation comparison between titanium and zirconia for 24 hours, zirconia showed less biofilm formation than titanium. Biofilm formation showed large deviation depending on individuals. As for formation comparison between zirconia and titanium, the degree of biofilm formation in zirconia was less than it was in titanium after a lapse of 24 hours. The result of biofilm formation in 72 hours trial show that zirconia has an inclination to formate less biofilm than it was in titanium. Conclusion: Based on the above results, we can conclude that early biofilm formation in oral cavity was influenced by difference of abutment materials.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.307-319
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• 2008

STATEMENT OF PROBLEM: It is known that an anodic oxidation technique, one of the methods for the implant surface treatment, remarkably increased surface area, enhanced wettability and accelerated the initial bone healing. Purpose: This study was performed to evaluate the wettability of anodized titanium surface which has a nanotubular structure, to assess osseointegration after the placement of implant with nano-size tubes on tibia of rats and to analyze quantitatively transferable rhBMP-2 on each surface. MATERIAL AND METHOD: Four different kinds of surface-treated titanium discs (polished (machined surface) group, micro (blasting surface) group, nano (anodizedmachined surface) group, and nano-micro (anodized-blasting surface) group) were fabricated (n=10). Three different media were chosen to measure the surface contact angles; distilled water, plasma and rhBMP-2 solution. After a single drop (0.025 $m{\ell}$) of solution, the picture was taken with the image camera, and contact angle was measured by using image analysis system. For the test of osseointegration, 2 kinds of anodized surface (anodized-machined surface, anodized-blasting surface) implants having 2.0 mm in diameter and 5.0 mm in length inserted into the tibia of Wistar rats. After 3 weeks, tibia were harvested and the specimens were stained with hematoxylin and eosin for histological analysis. To test the possibility of drug delivery, after soaking sample groups in the concentration of 250 ng/$m{\ell}$l of rhBMP-2 for 48 hours, the excess solution of rhBMP-2 were removed. After that, they were lyophilized for 24 hours, and then the rhBMP-2 on the surface of titanium was resolved for 72 hours in PBS. All the extracted solution was analyzed by ELISA. One-way analysis of variance (ANOVA) was performed on the data. RESULTS: The wettability is improved by anodic oxidation. The best wettability was shown on the nano-micro group, and it was followed by nano group, micro group, and polished group. In the histological findings, all implants showed good healing and the new bone formation were observed along the implant surface. After 3 days, nano-micro group delivered the most amount of rhBMP-2, followed by nano group, micro group, and polished group. CONCLUSION: It indicated that anodic oxidation on blasting surface produce functionally graded nano-micro porous structure and enhance hydrophilicity of the surface and osseointegration. The findings suggest that the nano-micro porous structure could be a useful carrier of osteogenic molecules like rhBMP-2.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.545-546
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• 2006

This study was performed to investigate the surface properties of electrochemically oxidized pure titanium by anodic spark discharging method. Commercially pure titanium plates of $10{\times}20{\times}1[mm]$ in dimensions were polished sequentially emery paper. Anodizing was performed at current density of $76.2\;[mA/cm^2]$, application voltage of 290, 350, 400 [V] using a regulated DC power supply, which allowed automatic transition constant current when a preset maximum voltage has been reached. The Ti surface oxided films was characterized by scanning electron microscope(SEM). The precipitation of HA(Hydroxyapatite) crystals on anodized surface was greatly accelerated by hydrothermal treatment. The concentrations of DL-$\alpha$-Glycerolphosphate Magnesiurn(DL-$\alpha$-GP-Mg) salt and Ca acetate in an electrolyte was highly affected the precipitation of HA crystals converted by Ti Anodized oxide films by Shape of Impulse Voltage.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.3
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• pp.343-355
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• 2006

Statement of problem. The success of osseointegration can be enhanced with an implant that has improved surface characteristics. Anodic oxidation is one of the surface modifying method to achieve osseointegration. Voltage of anodic oxidation can change surface characteristics and cell activity Purpose. This study was performed to evaluate MG63 cell responses such as affinity, proliferation and to compare surface characteristics of anodic oxidized titanium in various voltage. Material and method. The disks for cell culture were fabricated from grade 3 commercially pure titanium,1 m in thickness and 12 mm in diameter. Surfaces of 4 different roughness were prepared. Group 1 had a machined surface, used as control. Group 2 was anodized under 220 V, group 3 was anodized under 300 V and group 4 was anodized under 320 V. The microtopography of specimens was observed by scanning electron microscope (JSM-840A, JEOL, Japan) and atomic force microscope(Autoprobe CP, Park Scientific Instrument, USA). The surface roughness was measured by confocal laser scanning microscope(Pascal, LSM5, Zeiss, Germany). The crystal structure of the titanium surface was analyzed with x-ray diffractometer(D8 advanced, Broker, Germany). MG63 osteoblast-like cells were cultured on these specimens. The cell morpholgy was observed by field emission electron microscope(Hitachi S-4700, Japan). The cell metabolic and proliferative activity was evaluated by MTT assay Results and conclusion. With in limitations of this in vitro study, the following conclusions were drawn. 1. In anodizing titanium surface, we could see pores which did not show in control group. In higher anodizing voltage, pore size was increased. 2. In anodizing titanium surface, we could see anatase. In higher anodizing voltage, thicker oxide layer increased crystallinity(anatase, anatase and rutile mixed). 3. MG63 cells showed more irregular, polarized and polygonal shape and developed more lamellipodi in anodizing group as voltage increased. 4. The activity of cells in MTT assay increased significantly in group 3 and 4 in comparison with group 1 and 2. However, there was no difference between group 3 and 4 at P<0.05. Proliferation of MG63 cells increased significantly in pore size($3-5.5{\mu}m$) of group 3 and 4 in comparison with in pore size($0.2-1{\mu}m$ ) of group 2.