• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.120-125
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• 2016

Purpose: The purpose of this study is to identify the effect of mesenchymal stem cell proliferation on recombinant human transforming growth factor-beta (rhTGF-${\beta}2$) / poly (D,L-lactide-co-glycolide) (PLGA) treated titanium discs by electrospray. Materials and methods: Anodized titanium surface coated with PLGA was used for a control group to compare anodized titanium surface coated with 125 ng/ml and 500 ng/ml rhTGF-${\beta}2$ as test groups. Atomic force microscope (AFM) test was utilized to determine the difference in coating surface roughness, and field-emission scanning electron microscopy (FE-SEM) was taken to visualize even distribution of coating particles on titanium discs. The mesenchymal stem cell proliferation was tested by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl-tetrazolium bromide) assay on 1st, 4th, 7th days. Results: According to AFM results, there was no statistically significant difference in titanium discs treated with PLGA and with rhTGF-${\beta}2$/PLGA (P>.05). MTT assay test results showed that there was statistically significant difference in mesenchymal stem cell proliferation on test groups compared to control groups at 7th day, and cell viability on discs coated with rhTGF-${\beta}2$ was significantly higher than control groups (P<.05). Conclusion: Titanium surface coated with rhTGF-${\beta}2$/PLGA shows statistically significant higher cell proliferation and the titanium surface coated with the higher concentration of rhTGF-${\beta}2$ presents faster cell growth activity.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.5
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• pp.383-393
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• 2007

The aim of the present study is to investigate the effect of anodized surface of osseointegration implants by using of resonance frequency analysis (RFA) and histomorphometric analysis. A total of 96 screw-shaped implants were devided into 4 groups. Seventy-two implants were prepared by electrochemical oxidation with 3 different ways; Group 1 (n=24) were prepared at galvanostatic mode in 0.25M sulfuric acid and phosphoric acid, Group 2 (n=24) were prepared at galvanostatic mode in calcium glycerophosphate and calcium acetate, and Group 3 (n=24) were prepared at galvanostatic mode in 0.25M sulfuric acid and phosphoric acid followed by Calcium metaphosphate(CMP) coating. Control group (n=24) were the RBM surfaced implants. The implants were placed in the mandibles of 12 mini pigs. Bone tissue responses were evaluated by resonance frequency analysis(RFA) and histomorphometric analysis that were undertaken at 2, 4 and 6weeks after implant placement. The following result were obtained. 1. Twenty-two of 96 implants (4 in control group, 5 in group 1, 7 in group 2, and 6 in group 3) were failed due to faliure of osseoitegration. The failure rate of osseointegration was 22.9%. 2. The mean values of RFA in control, group 2 and groups 3 showed the similar values, but there was no significant difference among groups. 3. Histomorphometric evaluation demonstrated significantly higher bone-to-implant contact ratio in group 2 at 3 and 4 weeks after implant placement than other groups (p<0.05), but there was no significant difference among groups at 6weeks after implant placement.

• 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.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.79-79
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• 2017

Metallic biomaterials have been mainly used for the fabrication of medical devices for the replacement of hard tissue such as artificial hip joints, bone plates, and dental implants. Because they are very reliable on the viewpoint of mechanical performance. This trend is expected to continue. Especially, Ti and Ti alloys are bioinert. So, they do not chemically bond to the bone, whereas they physically bond with bone tissue. For their poor surface biocompatibility, the surface of Ti alloys has to be modified to improve the surface osteoinductivity. Recently, ceramic-like coatings on titanium, produced by plasma electrolytic oxidation (PEO), have been developed with calciumand phosphorus-enriched surfaces. A lso included the influences of coatings, which can accelerate healing and cell integration, as well as improve tribological properties. However, the adhesions of these coatings to the Ti surface need to be improved for clinical use. Particularly Silicon (Si) has been found to be essential for normal bone, cartilage growth and development. This hydroxyapatite, modified with the inclusion of small concentrations of silicon has been demonstrating to improve the osteoblast proliferation and the bone extracellular matrix production. Strontium-containing hydroxyapatite (Sr-HA) was designed as a filling material to improve the biocompatibility of bone cement. In vitro, the presence of strontium in the coating enhances osteoblast activity and differentiation, whereas it inhibits osteoclast production and proliferation. The objective of this work was to study Morphology of bone-like apatite formation on Sr and Si-doped hydroxyapatite surface of Ti-6Al-4V alloy after plasma electrolytic oxidation. Anodized alloys was prepared at 270V~300V voltages with various concentrations of Si and Sr ions. Bone-like apatite formation was carried out in SBF solution. The morphology of PEO, phase and composition of oxide surface of Ti-6Al-4V alloys were examined by FE-SEM, EDS, and XRD.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.285-291
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• 2012

Purpose: This study was conducted to identify the surface characteristics of titanium discs coated with MS275/PLGA by electrospray and which is effective to mesenchymal stem cell proliferation. Materials and methods: We used anodized surface coated with PLGA as a control group and anodized surface coated with MS275 $0.5{\mu}M$, $1{\mu}M$, $1.5{\mu}M$ as test groups. To examine that the coating particles are nanometer sized, FE-SEM was used and AFM was utilized to determine the difference of coating surface roughness. We checked the mesenchymal stem cell proliferation by using MTT assay on $1^{st}$, $4^{th}$, $7^{th}$ days. Results: There was no significant difference between control groups and test groups in AFM results (P>.05). In MTT assay results, mesenchymal stem cell proliferation was increased with time, at $7^{th}$ day, cell viability on discs coated with $1.5{\mu}M$ MS275 was significantly higher than control group (P<.05). As SEM showed, the number of cells on all discs was increased and the morphology of cell attachment was also wider and closer with time. Conclusion: Titanium surface coated with MS275/PLGA showed significantly higher cell proliferation and the more density of MS275 was dispersed on titanium discs, the faster cells grew.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.298-304
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• 2014

Purpose: This preliminary rabbit study was conducted to evaluate the effect of recombinant human transforming growth factor-${\beta}2$ (rhTGF-${\beta}2$)/poly lactic-co-glycolic acid (PLGA) coating on osseointegration of the titanium (Ti) implant. Materials and methods: Eight Ti implants were anodized with 300 voltages for three minutes. Four of those were coated with rhTGF-${\beta}2$/PLGA by an electrospray method as the experimental group. The implants were placed into tibiae of four New Zealand rabbits, two implants per a tibia, one implant per each group. After 3 and 6 weeks, every two rabbits were sacrificed and micro-computed tomography (microCT) was taken for histomorphometric analysis. Results: In scanning electron microscope (SEM) image, the surface of rhTGF-${\beta}2$/PLGA coated Ti implant showed well distributed particles. Although statistically insignificant, microCT analysis showed that experimental group has higher bone volume / total volume (BV/TV) and trabecular thickness (Tb.Th) values relatively. Cross sectional view also showed more newly formed bone in the experimental group. Conclusion: In the limitation of this study, rhTGF-${\beta}2$/PLGA particles coating on the Ti implant show the possibility of more favorable quantity of newly formed bone after implant installation.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.78-94
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• 2005

Purpose. The purpose of this study was to compare the effects of various surface treatments by measuring resonance frequency and histomorphometric analyses. Material and methods. In 5 adult dogs, the mandibular premolar were extracted. Six months later, 30 screw titanium implants (Dentium Co., Seoul, Korea) 6mm in length and 3.4mm in diameter, were placed in the mandibles of 5 dogs. Implants were divided into five groups following to surface treatment methods ; Group 1 is machined controls, Group 2 is sandblasted with large grit and acid-etched (SLA), Group 3 is anodized (Autoelectric Co., Korea, 660Hz, Duty10), Group 4 is hydroxyapatite(HA) coated by ion beam assisted deposition(E-beam), Group 5 is hydroxyapatite(HA) coated with Sol-gel coating process. Resonance frequency was measured implant placement immediately, and 3, 6 weeks and 10 weeks of healing perods. With the animal subject's sacrifice 10 weeks after implantation, implants were removed on bloc and histologic and computer-based histomorphometric analyses were performed. Histomorphometric analysis involved quantification of the entire bone to metal contact around the implants. Statistical analyses were performed using the SPSS for Windows (ver. 9.0 SPSS Inc.) Statistical differences were considered significant at P<0.05. Results. The results were as follows : 1) In five groups, mean value of resonance frequency analysis(RFA) were highest in group 5 (Sol-gel implant) at implantation and those of group 4 (E-beam)was highest at 10 weeks . but there was no correlation between surface treatments and RFA. 2) In all surface treatment groups, the RFA values of implants decreased until 3 weeks and increased to 10 weeks. 3) The percentage of direct bone-to-implant contact (BIC) had statistical significance between five groups in cancellous bone, (P<0.05) the percentage of bone density inside the thread had no statistical significance between five groups. (P>0.05) 4) There was a significant difference between cortical bone and cancellous bone in BIC. (P<0.05) and bone density. (P<0.05) 5) There was a correlation between the RFA value of implants at 10 weeks and BIC in cancellous bone, and between the RFA value of implants at 10 weeks and bone density in cortical bone. (P<0.05). Conclusions. These results indicate that surface treatment does not affect the implant stability in case of good bone quality.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.909-915
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• 2003

Anodic oxide films on aluminum play an important role as a dielectrics in aluminum electrolytic capacitor. In order to obtain the high capacitance, ZrO$_2$ films were coated on aluminum foils by sol-gel method and then, the properties of anodized films were studied. The coating and drying of the films were repeated 4-10 times and annealed at 300～$600^{\circ}C$ and the triple layer of ZrO$_2$/Al-ZrO$_{x}$ /Al$_2$O$_3$ was formed onto aluminum substrates after anodizing of ZrO$_2$/Al film. The thickness of $Al_2$O$_3$ layer was decreased with increasing the annealing temperature due to the densification of ZrO$_2$ film. The ZrO$_2$ films were crystallized even at 30$0^{\circ}C$ and showed nanocrystalline structure. The. capacitance of aluminum foil annealed at low temperature was higher than that at high temperature. The increase of capacitance was due to the high capacitance of ZrO$_2$ film annealed at low temperature. The capacitance of ZrO$_2$ coated aluminum increased about 3 times compared to that without a ZrO$_2$ layer after anodizing to 400 V. From these results, the aluminum foils with composite oxide layers are found to be applicable to the aluminum electrolytic capacitor.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.122-127
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• 2010

Purpose: The objective of this study was to investigate the effects of calcium phosphate coated titanium implant surface on bone response and implant stability at early stage of healing period of 3 weeks and later healing period of 6 weeks. Material and methods: A total of 24 machined, screw-shaped implants (Dentium Co., Ltd., Seoul, Korea) which dimensions were 3.3 mm in diameter and 5.0 mm in length, were used in this research. All implants (n = 24), made of commercially pure (grade IV) titanium, were divided into 2 groups. Twelve implants (n = 12) were machined without any surface modification (control). The test implants (n = 12) were anodized and coated with thin film (150nm) of calcium phosphate by electron-beam deposition. The implants were placed on the proximal surface of the rabbit tibiae. The bone to implant contact (BIC) ratios was evaluated after 3 and 6 weeks of implant insertion. Results: The BIC percentage of calcium phosphate coated implants ($70.8{\pm}18.9%$) was significantly higher than that of machined implants ($44.1{\pm}16.5%$) 3 weeks after implant insertion (P = 0.0264). However, there was no significant difference between the groups after 6 weeks of healing (P > .05). Conclusion: The histomorphometric evaluation of implant surface revealed that; 1. After 3 weeks early healing period, bone to implant contact (BIC) percentage of calcium phosphate coated implants (70.8%) was much greater than that of surface untreated machined implants (44.1%) with P = 0.0264. 2. After 6 weeks healing period, however, BIC percentage of calcium phosphate coated implants group (79.0%) was similar to the machined only implant group (78.6%). There was no statistical difference between two groups (P = 0.8074). 3. We found the significant deference between the control group and experimental group during the early healing period of 3 weeks. But no statistical difference was found between two groups during the later of 6 weeks.