• Journal of Periodontal and Implant Science
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• v.42 no.6
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• pp.248-255
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• 2012

Purpose: The aim of the present study was to evaluate the biological response of alkali- and heat-treated titanium-8tantalum-3niobium surfaces by cell proliferation and alkaline phosphatase (ALP) activity analysis. Methods: Commercial pure titanium (group cp-Ti) and alkali- and heat-treated titanium-8tantalum-3niobium (group AHT) disks were prepared. The surface properties were evaluated using scanning electron microscopy, energy dispersed spectroscopy and X-ray photoelectron spectroscopy (XPS). The surface roughness was evaluated by atomic force microscopy and a profilometer. The contact angle and surface energy were also analyzed. The biological response of fetal rat calvarial cells on group AHT was assessed by cell proliferation and ALP activity. Results: Group AHT showed a flake-like morphology microprofile and dense structure. XPS analysis of group AHT showed an increased amount of oxygen in the basic hydroxyl residue of titanium hydroxide groups compared with group cp-Ti. The surface roughness (Ra) measured by a profilometer showed no significant difference (P>0.05). Group AHT showed a lower contact angle and higher surface energy than group cp-Ti. Cell proliferation on group AHT surfaces was significantly higher than on group cp-Ti surfaces (P<0.05). In comparison to group cp-Ti, group AHT enhanced ALP activity (P<0.05). Conclusions: These results suggest that group AHT stimulates osteoblast differentiation.

• 대한치주과학회:학술대회논문집
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• 2002.11a
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• pp.34-35
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• 2002

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.545-559
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• 1998

Magnoliae cortex has been used as a drug for treatment of fractures in Chinese medicine and safflower(Carthamus tinctorius $Linn{\acute{e}}$) has been traditionally used for treatment of blood stasis. The purpose of present study was to examine the biologic effects of magnoliae cortex extract and safflower extract mixture(MSM) on human periodontal ligament cells and fetal rat calvarial osteoblasts and on healing of rat calvarial defects. The ethanolic extracts of magnoliae cortex(MCE), safflower seed(SSE), Zea May L(ZML) were prepared as positive control group. MSM mixed to the ratios of 1 : 1, 1 : 2, 1 : 5 and 1 : 10 were used as test group. The effects of each agents on the growth and survival, ALPase activity, cell proliferation and tissue regenerative effect of each extracts was evaluated by histomorphometric measuring of newly formed bone on the 8 mm defect in rat calvaria after oral administration of 2 ratio groups(1 : 5 and 1 : 10) at 3 different doses (0.1, 0.25 and 0.5g/kg per day). MSM stimulated the growth and survival rate of osteoblasts and PDL cells more than any other agents. The growth and survival rate were increased as the proportion of safflower seed extract was increased. MCE, SSE, ZML stimulated the ALPase activity of osteoblast and PDL cell in comparison to the negative control group. But all groups of MSM regardless of ratio of safflower seed extract stimulated the ALPase activity than any other agent. The ALPase activity was also increased as the proportion of safflower seed extract was increased. Although MCE, SSE, ZML stimulated the proliferation of osteoblasts. 1 : 5 and 1 : 10 ratio MSM showed significant increase in stimulation of proliferation of osteoblasts. No agent significantly increased proliferation of PDL cells. Significant new bone formation were seen where 1 : 5 ratio, 0.5g/kg group and 1 : 10 ratio, 0.25, 0.5g/kg groups were used. These results show that magnoliae cortex extract and safflower seed extract mixture can potentially increase bone regeneration ability.

• Journal of Life Science
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• v.26 no.3
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• pp.331-337
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• 2016

Although fibroblast growth factor 23 (FGF23) is exclusively produced in osteoblasts and osteocytes, its main target is the kidney, where it decreases phosphate reabsorption by suppressing Na-phosphate cotransporters. Independently of its action on phosphate homeostasis, FGF23 also inhibits bone formation in vivo. In a calvarial osteoblastic cell model, FGF23 was shown to negatively affect extracellular matrix mineralization. This study investigated whether FGF23 had similar effects on osteoblast maturation, including differentiation and mineralization of bone marrow-derived mesenchymal stem cells (MSCs). D1 MSCs were cultured in an osteogenic medium containing β-glycerophosphate, ascorbic acid, and dexamethazone. Osteoblastic differentiation was evaluated by alkaline phosphatase (Alp) staining, and matrix mineralization was evaluated by alizarin red staining and calcium deposition. The expression of differentiation-stimulating genes Runx2, Alp, and osteocalcin and mineralization-inhibiting genes Enpp1 and Ank was analyzed using semiquantitative RT-PCR. Supraphysiological doses of FGF23 did not stimulate proliferation or osteoblastic differentiation of MSCs. Matrix mineralization 1, 2, and 3 weeks after the FGF23 treatment did not vary between control and FGF23 groups, although time-dependent enhancement of mineralization was obvious. Calcium deposition was also unchanged after the FGF23 treatment. mRNA expression levels of differentiation- and mineralization-related genes were also similar between the groups. Despite these negative findings, FGF23 signaling through FGF receptors seemed to function normally, with phosphorylation of the Erk protein more evident in the FGF23 group than in controls. These findings suggest that unlike calvarial osteoblasts, FGF23 is not likely to affect osteoblastic differentiation and mineralization of MSCs.

• Molecules and Cells
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• v.38 no.7
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• pp.643-650
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• 2015

The use of conditioned medium from mesenchymal stem cells may be a feasible approach for regeneration of bone defects through secretion of various components of mesenchymal stem cells such as cytokines, chemokines, and growth factors. Mesenchymal stem cells secrete and accumulate multiple factors in conditioned medium under specific physiological conditions. In this study, we investigated whether the conditioned medium collected under hypoxic condition could effectively influence bone regeneration through enhanced migration and adhesion of endogenous mesenchymal stem cells. Cell migration and adhesion abilities were increased through overexpression of intercellular adhesion molecule-1 in hypoxic conditioned medium treated group. Intercellular adhesion molecule-1 was upregulated by microRNA-221 in mesenchymal stem cells because microRNAs are key regulators of various biological functions via gene expression. To investigate the effects in vivo, evaluation of bone regeneration by computed tomography and histological assays revealed that osteogenesis was enhanced in the hypoxic conditioned medium group relative to the other groups. These results suggest that behavioral changes of endogenous mesenchymal stem cells through microRNA-221 targeted-intercellular adhesion molecule-1 expression under hypoxic conditions may be a potential treatment for patients with bone defects.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.851-870
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• 2000

The major goals of periodontal therapy is the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chitin. Chitin is second only to cellulose as the most abundant natural biopolymer. It is a structural component of the exoskeleton of invertebrates(e.g., shrimp, crabs, lobsters), of the cell wall of fungi, and of the cuticle of insects. Chitosan is a derivative of chitin made by deacetylation of side chains. Many experiments using chitosan in various animal models have proven its beneficial effects. The aim of this study is to evaluate the osteogenesis of chitosan on the calvarial critical size defect in Sprague Dawley rats. An 8 mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into two groups: Untreated control group versus experimental group with 50mg of soluble chitosan gel. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric and radiodensitometric analyses. The results are as follows: 1. The length of newly formed bone in the defects was $102.91{\pm}25.46{\mu}m$, $219.46{\pm}97.81{\mu}m$ at the 2 weeks, $130.95{\pm}39.24{\mu}m$, $212.39{\pm}89.22{\mu}m$ at the 4 weeks, $181.53{\pm}76.35{\mu}m$ and $257.12{\pm}51.22{\mu}m$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. But, there was no statistically significant difference between the two groups. 2. The area of newly formed bone in the defects was $2962.06{\pm}1284.48{\mu}m^2$, $5194.88{\pm}1247.88{\mu}m^2$ at the 2 weeks, $5103.25{\pm}1375.88{\mu}m^2$, $7751.43{\pm}2228.20{\mu}m^2$ at the 4 weeks and $8046.20{\pm}818.99{\mu}m^2$, $15578.57{\pm}5606.55{\mu}m^2$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. 3. The density of newly formed bone in the defects was $14.26{\pm}6.33%$, $27.91{\pm}6.65%$ at the 2 weeks, $20.06{\pm}9.07%$, $27.86{\pm}8.20%$ at the 4 weeks and $22.99{\pm}3.76%$, $32.17{\pm}6.38%$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. These results suggest that the use of chitosan on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.114-125
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• 2002

This study was designed to evaluate the influence of fibroblasts or connective tissue from mouse oral mucosa on differentiation of neonatal mouse calvaria-derived osteoblasts and mineralization of bone nodules. Primary cell cultures from mouse calvarial osteoblasts and 2-4 passaged fibroblasts from oral mucosa were co-cultured in monolayer cultures, devided into 6 experimental group according to cell density or cell confluency. Osteoblasts were also co-cultured with fibroblasts in $Transwell^{(R)}$ culture plate with different co-cultured period according to osteoblast differentiation. The alkaline phosphatase activity were measured in monolayer cultures and cultures using $Transwell^{(R)}$. The mineralized bone nodules were presented by Von Kossa staining and density of mineralized nodules was measured by image analysis. The connective tissues with or without osteoblast seeding were cultured and examined histologically by Von Kossa and Trichrome Goldner staining. The results were as follows; 1. Prolonged maturation of matrix and delayed mineralization of bone nodules were resulted in monolayer cultures. 2. Co-culture of fibroblast with osteoblast using $Transwell^{(R)}$ during osteoblast proliferation stage stimulated proliferation of osteoblasts and increased alkaline phosphatase activity and mineralization of bone nodules. 3. Co-culture of fibroblast with osteoblast using $Transwell^{(R)}$ during matrix mineralization stage decreased and delayed mineralization of bone nodules. 4. In vitro cultured connective tissue with osteoblast seeding resulted in proliferation of osteoblasts and matrix formation with mineralization.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.151-163
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• 1997

The purpose of this study was to evaluate on the biodegradability, biocompatibility and tissue regenerative capacity of synthetic biodegradable $mernbranes-Resolut^{(R)}$, $Guidor^{(R)}$ and $Biomesh^{(R)}$. To evaluate the cell attachment on the membranes, in vitro, the number of gingival fibroblasts attached to each membrane was counted by hemocytometer. Cytotoxicity test for the membranes was performed by MTT test with gingival fibroblast For evaluation of guided- bone regenerative potential, the amount of new bone formation in the rat calvarial defects(5mm in diameter) beneath the membranes was observed for two weeks and examined of the specimens by Massons trichrome staining. Biodegradability was observed for 2, 4, 8 and 12 weeks after implantation of each materials under the skin of rats and examined the specimens with H & E staining. The number of cell attachment were the greatest in $Biomesh^{(R)}$ and followed by $Resolut^{(R)}$. Cell viability of three membranes was almost similar levels. Biodegradability of $Resolut^{(R)}$ was the highest among three membrane and the potential of guided bone regeneration was the greatest in the $Biomesh^{(R)}$ and $Resolut^{(R)}$ was followed. These results suggested that commercially available biodegradable membranes were non-toxic and highly potential to guided bone regeneration.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.1-23
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• 2001

Chitosan is biodegradable natural polymer that has been demonstrated its ability to improve wound healing, and calcium metaphosphate(CMP) is a unique class of phosphate minerals having a polymeric structure. In this study, chitosan/CMP and platelet derived growth factor(PDGF-BB) loaded chitosan/CMP sponges were developed, and the effect of the sponges on bone regeneration and their possibility as scaffolds for bone formation by three-dimensional osteoblast culture were examined. PDGF-BB loaded chitosan/CMP sponges were prepared by freeze-drying of a mixture of chitosan solution and CMP powder, and soaking in a PDGF-BB solution. Fabricated sponge retained its 3-dimensional porous structure with $100-200\;{\mu}m$ pores. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with $^{125}I-labeled$ PDGF-BB. In order to examine their possibility as scaffolds for bone formation, fetal rat calvarial osteoblastic cells were isolated, cultured, and seeded into the sponges. The cell-sponge constructs were cultured for 28 days. Cell proliferation, alkaline phosphatase activity were measured at 1, 7, 14 and 28 days, and histologic examination was performed. In order to examine the effect on the healing of bone defect, the sponges were implanted into rat calvarial defects. Rats were sacrificed 2 and 4 weeks after implantation and histologic and histomorphometrical examination were performed. An effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. PDGF-BB loaded chitosan/CMP sponges supported the proliferation of seeded osteoblastic cells as well as their differentiation as indicated by high alkaline phosphatase activities. Histologic findings indicated that seeded osteoblastic cells well attached to sponge matrices and proliferated in a multi-layer fashion. In the experiments of implantation in rat calvarial defects, histologic and histomorphometric examination revealed that chitosan/CMP sponge promoted osseous healing as compared to controls. PDGF-BB loaded chitosan/CMP sponge further echanced bone regeneration. These results suggested that PDGF-BB loaded chitosan/CMP sponge was a feasable scaffolding material to grow osteoblast in a three-dimentional structure for transplantation into a site for bone regeneration.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.345-353
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• 2002

Bone morphogenetic proteins(BMPs) are secretory signal molecules which have a variety of regulatory functions during morphogenesis and cell differentiation. To evaluate roles of BMPs and their receptors on mouse sagittal suture development, we have examined their expression patterns in serial sections of sagittal sutures by in situ hybridization during embryonic stages(E15-E18). BMP-2 and BMP-3 were expressed in the osteogenic front and parietal bone on embryonic 15day, from E16 in hair follicle. BMP-4 was strongly expressed in the osteogenic front and weakly expressed in the mesenchyme and parietal bone. BMP-S was expressed in the hair follicles. BMP-6 was not expressed in this study. BMP-7 was expressed in parietal bone during embryonic stage. BMPR-IB was expressed in the osteogenic front, but BMPR-IA was not. From these datas, we suggest that the BMP-4 regulates the early commitment of mesenchymal cells to the osteogenic lineages, the BMP-2 and BMP-3 may be involved in regulating the differentiation of osteoblast precursor cells. BMP-7 was involved in maintenance of differentiated osteoblasts. BMPs were key signaling molecules that regulate early calvarial bone morphogenesis, mediated by BMPR-IB.