• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.80-80
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• 2017

Titanium and its alloys that have a good biocompatibility, corrosion resistance, and mechanical properties such as hardness and wear resistance are widely used in dental and orthopedic implant applications. However, they do not form a chemical bond with bone tissue. Plasma electrolytic oxidation (PEO) that combines the high voltage spark and electro-chemical oxidation is a novel method to form ceramic coatings on light metals such as tita-nium and its alloys. This is an excellent re-producibility and economical, because the size and shape control of the nano-structure is relatively easy. Silicon (Si), manganese (Mn), and magne-sium (Mg) have a useful to bone. Particularly, Si has been found to be essential for normal bone, cartilage growth, and development. Mn influences regulation of bone remodeling be-cause its low content in body is connected with the rise of the concentration of calcium, phosphates and phosphatase out of cells. Pre-studies have shown that Mg plays very im-portant roles in essential for normal growth and metabolism of skeletal tissue in verte-brates and can be detected as minor constitu-ents in teeth and bone. In this study, Electrochemical behavior of plasma electrolytic oxidized films formed in solution containing Mn, Mg and Si ions were researched using various experimental in-struments. A series of Si-Mn-Mg coatings are produced on Ti dental implant using PEO, with the substitution degree, respectively, at 5 and 10%. The potentiodynamic polarization and AC impedance tests for corrosion behav-iors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV. Also, AC impedance was performed at frequencies anging from 10MHz to 100kHz for corrosion resistance.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.152-152
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• 2017

Titanium and its alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element,such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}$-stabilizer and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Silicon (Si) and magnesium (Mg) has a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. In vitro studies have shown that Mg plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Therefore, in this study, Si and Mg coatings on the hydroxyapatite film formed Ti-29Nb-xHf alloys by plasma electrolyte oxidation has been investigated using several experimental techniques. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. The electrolyte was Si and Mg ions containing calcium acetate monohydrate + calcium glycerophosphate at room temperature. The microstructure, phase and composition of Si and Mg coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.154-154
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• 2017

Ti-6Al-4V alloys are widely used as metal-lic biomaterials in dentistry and orthopedics due to its excellent biocompatibility and me-chanical properties. However, because of low biological activity, it is difficult to form bone growth directly on the surface of titanium implants. For this reason, surface treatment of plasma electrolytic oxidation(PEO) was used for dental implants. To enhance bioac-tivity on the surface, strontium(Sr) and sili-con(Si) ions can be added to PEO treated sur-face in the electrolyte containing these ions. The presence of Sr in the coating enhances osteoblast activity and differentiation, where-as it inhibits osteoclast production and prolif-eration. And Si has been found to be essen-tial for normal bone, cartilage growth, and development. In this study, electrochemical characteristics of Ca, P, Sr, and Si ions from PEO-treated Ti-6Al-4V alloy surface was re-searched using various experimental instruments. DC power is used and Ti-6Al-4V al-loy was subjected to a voltage of 280 V for 3 minutes in the electrolyte containing 5, 10, 20M% Sr ion and 5M% Si ion. The morphol-ogies of PEO-treated Ti-6Al-4V alloy by electrochemical anodization were examined by field-emission scanning electron micro-scopes (FE-SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and corrosion analysis using AC impedance and potentiodynamic polarization test in 0.9% NaCl solution at similar body tempera-ture using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.143-149
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• 2011

Arthritis is a common disease in aged people, and is clinically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Although common symptoms such as pain are present, the underlying pathological mechanisms are slightly different. Therefore, the objectives of the present study were to compare joint damage induced by RA and OA by analyzing the major morphological and molecular differences, and to propose a suitable therapeutic intervention based on the pathophysiological conditions of bones and joints. For the RA animal model, 8-week-old DBA1/J mice were immunized with bovine type II collagen emulsified in complete Freund's adjuvant (CFA). Normal C57BL/6 mice (over 2 years of age) were used for OA. The clinical arthritis score was calculated using a subjective scoring system, and paw thicknesses were measured using calipers. The serum TNF ${\alpha}$ level was analyzed using an ELISA kit. Micro-CT was used to identify pathological characteristics and morphological changes. In collagen-induced RA mice, there were increased ankle joint volumes and clinical scores (p<0.01). The concentration of TNF ${\alpha}$ was significantly increased from 3 to 7 weeks after immunization. Micro-CT images showed trabecular bone destruction, pannus formation, and subchondral region destruction in RA mice. OA among aged mice showed narrowed joint spaces and breakdown of articular cartilage. This study suggests that a careful therapeutic intervention between RA and OA is required, and it should be based on morphological alteration of bone and joint.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.202-202
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• 2011

The research of 3-dimensional (3-D) scaffold for tissue engineering has been widely investigated as the importance of the 3-D scaffold increased. 3-D scaffold is needed to support for cells to proliferate and maintain their biological functions. Furthermore, its architecture defines the shape of the new bone and cartilage growth. Polycaprolactone (PCL) has been one of the most promising materials for fabricating 3-D scaffold owing to its excellent mechanical property and biocompatibility. However, there are practical problems for using it, in vitro and in vivo; extracellular matrix components and nutrients cannot penetrate into the inner space of scaffold, due to its hydrophobic property, and thus cell seeding and attachment onto the inner surface remain as a challenge. Thus, the surface modification strategy of 3-D PCL scaffold is prerequisite for successful tissue engineering. Herein, we utilized a mussel-inspired approach for surface modification of 3-D PCL scaffold. Modification of 3-D PCL scaffolds was carried out by simple immersion of scaffolds into the dopamine solution and stimulated body fluid, and as a result, hydroxyapatite-immobilized 3-D PCL scaffolds were obtained. After surface modification, the wettability of 3-D PCL scaffold was considerably changed, and infiltration of the pre-osteoblastic cells into the 3-D scaffold followed by the attachment onto the surface was successfully achieved.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.533-539
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• 2009

In this study, the femur, the tibia, the articular cartilage and the menisci are three dimensionally reconstructed using MR images of healthy knee joint in full extension of 26-year-old male. Three dimensional finite element model of the knee joint is fabricated on the reconstructed model. Also, the FE models of ligaments and tendons are attached on the biologically suitable position of the FE model. Bones, articular cartilages and menisci are considered as homogeneous, isotropic and linear elastic materials, and ligaments and tendons are modeled as truss element and nonlinear elastic springs. The numerical results show the contact pressure and the von Mises stress distribution in the soft tissues such as articular cartilages and menisci which can be regarded as important parameters to estimate the failure of the tissues and the pain of the patients.

• The korean journal of orthodontics
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• v.42 no.6
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• pp.307-317
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• 2012

Objective: The purpose of this study was to investigate the isolation and characterization of multipotent human periodontal ligament (PDL) stem cells and to assess their ability to differentiate into bone, cartilage, and adipose tissue. Methods: PDL stem cells were isolated from 7 extracted human premolar teeth. Human PDL cells were expanded in culture, stained using anti-CD29, -CD34, -CD44, and -STRO-1 antibodies, and sorted by fluorescent activated cell sorting (FACS). Gingival fibroblasts (GFs) served as a positive control. PDL stem cells and GFs were cultured using standard conditions conducive for osteogenic, chondrogenic, or adipogenic differentiation. Results: An average of $152.8{\pm}27.6$ colony-forming units was present at day 7 in cultures of PDL stem cells. At day 4, PDL stem cells exhibited a significant increase in proliferation (p < 0.05), reaching nearly double the proliferation rate of GFs. About $5.6{\pm}4.5%$ of cells in human PDL tissues were strongly STRO-1-positive. In osteogenic cultures, calcium nodules were observed by day 21 in PDL stem cells, which showed more intense calcium staining than GF cultures. In adipogenic cultures, both cell populations showed positive Oil Red O staining by day 21. Additionally, in chondrogenic cultures, PDL stem cells expressed collagen type II by day 21. Conclusions: The PDL contains multipotent stem cells that have the potential to differentiate into osteoblasts, chondrocytes, and adipocytes. This adult PDL stem cell population can be utilized as potential sources of PDL in tissue engineering applications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.1
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• pp.7-15
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• 2010

Complex human tissues harbor stem cells and precursor cells, which are responsible for tissue development or repair. Recently, dental tissues such as dental pulp, periodontal ligament (PDL), dental follicle have been identified as easily accessible sources of undifferentiated cells. These tissues contain mesenchymal stem cells that can be differentiate into bone, cartilage, fat or muscle by exposing them to specific growth conditions. In this study, the authors procured the stem cell from pulp, PDL, and dental follicle and differentiate them into osteoblast and examine the bone induction capacity. Dental pulp stem cell (DPSC), periodontal ligament stem cell (PDLSC), and dental follicle precursor cell (DFPC) were obtained from human 3rd molar and cultured. Each cell was analyzed for presence of stem cell by fluorescence activated cell sorter (FACs) against CD44, CD105 and CD34, CD45. Each stem cell was cultured, expanded and grown in an osteogenic culture medium to allow formation of a layer of extracellular bone matrix. Osteogenic pathway was checked by alizarin red staining, alkaline phosphatase (ALP) activity test and RT-PCR for ALP and osteocalcin (OCN) gene expression. According to results from FACs, mesenchymal stem cell existed in pulp, PDL, and dental follicle. As culturing with bone differentiation medium, stem cells were differentiated to osteoblast like cell. Compare with stem cell from pulp, PDL and dental follicle-originated stem cell has more osteogenic effect and it was assumed that the character of donor cell was able to affect on differential potency of stem cell. From this article, we are able to verify the pulp, PDL, and dental follicle from extracted tooth, and these can be a source of osteoblast and stem cell for tissue engineering.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.353-361
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• 2016

This study was to demonstrate the anti-inflammation effect using extracts derived from fusion-fermentation to add the function of Araliae Continentalis Radix (fACR). Since there are limitations to the use of ACR, available strains were selected through fermentation using lactobacillus strains, and the increases in total amount of polyphenols and amino acids was confirmed through comparison with Hot Water Extract of ACR. To determine the anti-inflammatory effect of the fACR was measure cytokine inflammation associated with arthritis, the arthritis when cartilage destruction is accompanied mainly MMP-9 activity was confirmed to evaluate the inhibition effect. These results show that fermentation using lactobacillus increases major biological activities and inflammatory response-restraining effects of ACR. This study is expected to be a basis for studying the preventive effect of fACR on arthritis.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.4
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• pp.1889-1896
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• 2019

Background: Because of the lack of accurate values for applied forces in manual therapy, manual therapists relies on the magnitude of the individual's perception during applying the force. However, excessive loading maneuvers carry risks for patients. Objective: To establish the relationship between the maximal force applied to swine skin with the specific region, sex, and baseline parameters of the subject. Design: Ex-vivo Study and laboratory Experimental research Methods: 3.5 kg of Korean pork sirloin that is a piece of swine was handled and it was set 3 dimensions; #A; #B; #C. Forty-seven participants who has no experience in physical therapy randomly carried out the experiment, indicated to push each place of the pressure spots with same posture and process under supervision from the instructor who has over 15 years of manual therapy, and we measured the pressure force in each time. Results: The biggest pressure force was recorded in spot #A, and #B was represented after #C. Pressure on #A showed certain statistic relation with height (r=.317, p<.05) and weight (r=.434, p<.01); pressure on #B showed certain relation which has statistical meaning with only height (r=.401, p<.01); pressure on #C emerged to have statistic relationship with height (r=.308, p<.05)and weight (r=.428, p<.01). The age aspect revealed relation with pressure on #A, #B and #C, but that was not statistically significant. Conclusions: It can be inferred that there is the most loss of pressure in the area where cartilage is like an island in the middle.