• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.123-135
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• 2001

Several growth factors and polypeptides were studied for the regeneration of periodontal supporting tissues which had been lost due to periodontal disease. But these are not commonly used for regenerators of bone tissue or alveolar bone, because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many natural products, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, anti-inflammatory and regenerative potential or periodontal tissues. Cnidii Rhizoma, Rhinocerotis Cornu and Drynariae Rhizoma have been traditionally used as a drug for treatment of bone disease in oriental medicine. The purpose of this study was to examine the ability of alkaline phosphatase synthesis of MC3T3-E1 cells when above medicines were supplimented. MC3T3-E1 cells were cultured with ${\alpha}-MEM(negative control)$, dexamethasone(positive control), and each natural products for 3 and 5 days. And then ALP synthesis was measured by spectrophotometer for enzyme activity and by naphthol AS-BI staining for morphometry. Except Cnidii Rhizoma, all of the natural products of this study induced higher activity of ALP synthesis than controls. Among them Drynariae Rhizoma induced the highest activity. In the aspects of culturing time, all medicines did not showed the difference between 3 and 5 days, but $10^{-7}g/ml$ group of Rhinocerotis Corun showed significant increase at 3 days than at 5 days. These results indicate that several natural products have a inducing ability of ALP synthesis on osteoblasts.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.287-305
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• 2000

The purpose of this study is to evaluate the effects of bioresorbable membranes in guided bone regeneration of streptozotocin induced diabetic rats. 50 Sprague-Dawley rats were randomly categorized into 4 groups: Group 1 & 2 had 10 normal rats each and group 3 & 4 included 15 streptozotocin induced diabetic rats each. Defect measuring 7mm in diameter was formed on every rat calvarium. No membrane was used in groups 1 & 3 and membranes were used in groups 2 & 4. The rates were sacrificed at 2 and 4 weeks after defect formation. Routine histological specimens were prepared. Masson-trichrome and HE stain were done before light microscopy. Guided regenerative potential was evaluated by measuring the amount of new bone formation in the calvarial defect by histomorphometry. Following results were obtained. 1. New bone formation in the diabetic groups was significantly less that than in the normal groups regardless of membrane use(p<0.05). 2. In the comparison of new bone formation in the normal groups, membrane group showed significantly more bone formation(p<0.1). 3. When the amount of new bone formation was compared in the diabetic groups, more bone was formed in the membrane groups but the difference was not statistically significant.4. In the normal groups the amount of new bone formation was significantly greater at 4 weeks compared to that at2 weeks(p<0.05) but amount of bone regeneration at 4 weeks was not significantly greater than that at 2 weeks in both diabetic groups.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.751-765
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• 1999

Several growth factors and polypeptidesare not commonly yet used for regenerators of bone tissue or alveolar bone because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many natural medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, anti-inflammatory and regenerative potential of periodontal tissues. Olibanum, Myrrha, Phlomis Radix, and Cimicifugae Rhizoma have been traditionally used as a drug for treatment of bone disease in oriental medicine. The objective of this study was to examine the ability of alkaline phosphatase(ALP) synthesis of rat calvarial osteoblast(MC3T3-E1) when several natural medicines were supplemented. MC3T3-E1 cells were cultured with ${\alpha}$-MEM(negative control), dexamethasone(positive control), and each natural medicines for 3 and 5 days. And then ALP synthesis was measured by spectrophotometer for enzyme activity and by naphthol AS-BI staining for morphometry. All of the natural medicines induced higher activity of ALP synthesis than the negative controls. Especially Olibanumind uced the higher activity than the positive controls (p<0.05). In the aspects of culturing time, except Cimicifugae Rhizoma, the natural medicines induced higher activity of ALP synthesis at 5 days than at 3 days (p<0.05). In morphometry, all of the natural medicines showed statistical significance compared to the negative control (p<0.05). Myrrha a n d Phlomis Radix showed larger positively stained area at 5days than at 3 days, whereas the others did not showed the difference between at 5 and at 3 days(p<0.05). These results indicate that several natural medicines have an inducing ability of ALP synthesis in MC3T3-E1 cells.

• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.11-18
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• 2011

The periosteum contains multipotent cells that can differentiate into osteoblasts and chondrocytes. Cultured periosteum-derived cells (PDCs) have an osteogenic capacity. The purpose of this study was to evaluate the interaction of PDCs with bone graft biomaterial. After cell isolation from the calvarial periosteum of Sprague-Dawley rats, cultured PDCs were placed in critical-sized calvarial defects with beta-tricalcium phosphate (${\beta}$-TCP). All rats were sacrificed 8 weeks after bone graft surgery, and the bone regenerative ability of bone grafting sides was evaluated by plain radiography, micro-computed tomography (CT), and histological examination. PDCs grafted with ${\beta}$-TCP displayed enhanced calcification in the defect site, density of regenerated bone and new bone formation within the defect and its boundaries. Furthermore, these PDCs more efficiently regenerated new bone as compared to grafted ${\beta}$-TCP only. The results suggest that cultured PDCs have the potential to promote osteogenesis in bone defects.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.72-72
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• 2012

Lithium rechargeable batteries have been widely used as key power sources for portable devices for the last couple of decades. Their high energy density and power have allowed the proliferation of ever more complex portable devices such as cellular phones, laptops and PDA's. For larger scale applications, such as batteries in plug-in hybrid electric vehicles (PHEV) or power tools, higher standards of the battery, especially in term of the rate (power) capability and energy density, are required. In PHEV, the materials in the rechargeable battery must be able to charge and discharge (power capability) with sufficient speed to take advantage of regenerative braking and give the desirable power to accelerate the car. The driving mileage of the electric car is simply a function of the energy density of the batteries. Since the successful launch of recent Ni-MH (Nickel Metal Hydride)-based HEVs (Hybrid Electric Vehicles) in the market, there has been intense demand for the high power-capable Li battery with higher energy density and reduced cost to make HEV vehicles more efficient and reduce emissions. However, current Li rechargeable battery technology has to improve significantly to meet the requirements for HEV applications not to mention PHEV. In an effort to design and develop an advanced electrode material with high power and energy for Li rechargeable batteries, we approached to this in two different length scales - Atomic and Nano engineering of materials. In the atomic design of electrode materials, we have combined theoretical investigation using ab initio calculations with experimental realization. Based on fundamental understanding on Li diffusion, polaronic conduction, operating potential, electronic structure and atomic bonding nature of electrode materials by theoretical calculations, we could identify and define the problems of existing electrode materials, suggest possible strategy and experimentally improve the electrochemical property. This approach often leads to a design of completely new compounds with new crystal structures. In this seminar, I will talk about two examples of electrode material study under this approach; $LiNi_{0.5}Mn_{0.5}O_2$ based layered materials and olivine based multi-component systems. In the other scale of approach; nano engineering; the morphology of electrode materials are controlled in nano scales to explore new electrochemical properties arising from the limited length scales and nano scale electrode architecture. Power, energy and cycle stability are demonstrated to be sensitively affected by electrode architecture in nano scales. This part of story will be only given summarized in the talk.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.165-177
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• 1997

The purpose of this study was to perform on the biological activity of Magnolia and Zizyphi fructus extract mixtures on the wound healing of defected rat calvaria. For the determination of the mixture ratio of two extracts for oral administration, preliminary experiments were performed with the mixture combination of 2000 and $3000{\mu}g/ml$ of Magnolia extract, and also 20, 30, 200, 300, 2000 and $3000{\mu}g/ml$ of Zizyphi fructus extract, respectively and divided into 6 groups. The combination of extracts mixture were tested on the enhancing effect of cellular activity. The effect of the extracts mixture on the cellular activity was evaluated using MTT method and measured on the results with optical density by ELISA reader. The ability to tissue regeneration of the extracts mixture was performed by measuring new bone and new connective tissue regeneration on the 5mm defected rat calvaria for 1, 2 and 3 weeks after oral administration of 2 different dosages groups : 10:1(0.1g/kg) and 10:1(0.5g/kg). It was employed the same dosages of unsaponifiable fraction of Zea Mays L as positive controls. Each group of rat was sacrificed and en bloc section for histological examination. The effect on the cellular activity of each mixture ratio showed significantly higher in $2000{\mu}g/ml$ of Magnolia extract and $200{\mu}g/ml$ of Zizyphi fructus extract group to compare with other groups. These preliminary results showed that appropriate mixture ratio of two extracts was 10:1 of Magnolia and Zizyphi fructus extract. Histological examination on the activity of tissue regeneration of each group showed that 2weeks and 3weeks specimens of 0.5g/kg of 10:1 extract mixture of Magnolia and Ziziphi fructus administrated rat calvaria revealed significantly more osteoid and new bone formation of defected calvaria with unification of defected area than the specimens of any other negative and positive controls. Even though the specimen administrated the same dosages of unsaponifiable fraction of Zea Mays L, positive controls, showed the trend that they promote significantly the repair of calvarial defect, their bone reparative activities were less inductive than the same dosages of Magnolia and Ziziphi fructus extract mixture. These results implicated that the mixture of Magnolia and Zizyphi fructus extracts should be highly effective on the wound healing of bony defected site and might have potential possibilities as an useful drug to promote periodontal tissue regeneration.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.44-50
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• 2011

An immature tooth with infected pulp has numerous potential complications. Conventional apexification with calcium hydroxide has several disadvantages, including susceptibility to tooth fracture. This method does not promote continual root development. Pulp revascularization of a necrotic, immature permanent tooth will allow further development of the root and dentinal structure. Disinfection of the root canal system is a prerequisite for pulp revascularization and tissue regeneration. A combination of antibiotic drugs (ciprofloxacin, metronidazole, and minocycline) is effective for disinfection of necrotic pulp, and has been used successfully in regenerative endodontic treatment. These case reports involve the treatment of 3 immature permanent teeth with necrotic pulp using a 3-Mix paste and mineral trioxide aggregate. All cases showed the notable apical maturation with closure of the apex and increased thickness of dentinal walls. This approach suggests a paradigm shift in treating endodontically involved immature permanent teeth from the traditional apexification with calcium hydroxide to the conservative approach by providing a favorable environment for tissue regeneration.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.869-885
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• 2000

Fibroblasts are major cellular components of gingiva and periodontal ligament. They regulate the healing process after surgery or injury. Recently, many natural medicines, whose advantages are less side effects and possibility of long-term use, have been studied for their capacity, their anti-bacterial and anti-inflammatory effects and regenerative potential of periodontal tissues. Sophorae radix have been traditionally used as an anti-bacterial and antiinflammatory drug in oriental medicine. The purpose of present study was to investigate the effects of Sophorae radix extract on cell cycle progression and its molecular mechanism in human gingival fibroblasts. Sophorae radix extracts($100{\mu}g/ml$) notably increased cell proliferation and cell activity in the human gingival fibroblasts as compared to non-supplemented controls. There was an increase in the S phase and a decrease in the G1 phase in $100{\mu}g/ml$ of Sophorae radix extracts group as compared to non-supplemented controls. The level of cyclin E and cdk 2 protein in test group was higher than that of control groups. But that of cyclin D, cdk 4, and cdk 6 was not distinguished from controls. The level of p53 protein in test group was lower than that of controls, whereas that of p21 was not different. The level of pRB protein in test group was higher than that of controls, whereas that of p16 was lower. These results indicate that the increase of cell proliferation by Sophorae radix extracts may be due to the increased expression of cyclin E and cdk 2, and the decreased expression of p53 and p16 in human gingival fibroblasts.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.77-86
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• 2009

Purpose: Recombinant human bone morphogenetic protein-2(rhBMP-2) has been evaluated as potential candidates for periodontal and bone regenerative therapy. In spite of good prospects in BMP applications, there is economically unavailable for clinical use in dental area. The purpose of this study was to evaluate the osteogenic effect of rhBMP-2 produced by E.coli expression system. Materials and methods: Eight-mm critical-size calvarial defects were created in 48 male Sprague-Dawley rats. The animals were divided into 6 groups of 8 animals each. Each group received one of the following: Negative control(sham-surgery control), positive control(absorbable collagen sponge(ACS) alone) and experimental(ACS loaded with rhBMP-2). Defects were evaluated by histologic and histometric parameters following 2- and 8-week healing intervals. Results: The experimental group showed significant defect closure at 2 and 8weeks than the sham surgery and positive control groups. Moreover, the experimental group showed significantly greater new bone and augmented area than the other groups at both 2 and 8weeks. Conclusion: rhBMP-2 produced by E.coli expression system may be effective for bone regeneration.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.733-742
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• 2007

Bone morphogenetic proteins have been shown to possess significant osteoinSductive potential, but in order to take advantage of this effect for tissue engineering, carrier systems are essential. Successful carrier systems must enable vascular and cellular invasion, allowing BMP to act as a differentiation factor. The carrier should be reproducible, non-immunogenic, moldable, and space-providing, to define the contours of the resulting bone. The purpose of this study was to review available literature, in comparing various carriers of BMP on rat calvarial defect model. The following conclusions were deduced. 1. Bone regeneration of ACS/BMP, ${\beta}-TCP/BMP$, FFSS/BMP, $FFSS/{\beta}-TCP/BMP$, MBCP/BMP group were significantly greater than the control groups. 2. Bone density in the ACS/BMP group was greater than that in ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$ carrier group. 3. Bone regeneration in FFSS/BMP group was less than in ACS/BMP, ${\beta}-TCP/BMP$, MBCP/BMP group. However, New bone area of $FFSS/{\beta}-TCP/BMP$ carrier group were more greater than that of FFSS/BMP group. ACS, ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$, MBCP were used for carrier of BMP. However, an ideal carrier which was reproducible, non-immunogenic, moldable, and space-providing did not exist. Therefore, further investigation are required in developing a new carrier system.