• International Journal of Oral Biology
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• v.42 no.4
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• pp.191-196
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• 2017

Transglutaminase2 (TGM2) is a multi-functional calcium dependent enzyme that affects angiogenesis, apoptosis, differentiation, attachment, and changes in the extracellular matrix. However, its function in periodontal tissue has not yet been studied. The aim of this study was to investigate the association of the TGM2 expression and the modulation of inflammatory mediators in inflamed periodontal ligament (PDL) cells induced by pro-inflammatory cytokines such as Interleukin-$1{\beta}$ and the Tumor necrosis $factor-{\alpha}$. The expression of TGM2 was increased in the inflamed periodontal tissue and PDL cells. Over-expressed TGM2 in the PDL cells increased expression of MMP1, MMP3, IL-6, CXCL8, and PTGS2. Conversely, inhibition of TGM2 activity using LDN27219, a TGM2 inhibitor, resulted in decreased expression of MMP1, MMP3, IL-6, and CXCL8. The mRNA expression was confirmed by RT-PCR and quantified by qRT-PCR. Protein levels were also confirmed by immunofluoroscence staining. These results suggest that TGM2 plays an important role in the regulation of inflammatory mediators which exacerbate tissue damage in inflamed periodontal tissue.

• International Journal of Oral Biology
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• v.30 no.3
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• pp.105-110
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• 2005

Periodontitis is a chronic infectious disease that leads to the destruction, one of the major cause of tooth loss in human. Osteoclast Differentiation Factor(ODF), also called as Receptor activator of NF-${\kappa}B$ ligand(RANKL), a surface-associated ligand on bone marrow stromal cells and osteoblasts, activates its cognate receptor RANK on osteoclast progenitor cells, which leads to differentiation of these mononucleated precursor cells. Osteoprotegerin(OPG), a decoy receptor, is released from stromal cells and osteoblasts to inhibit the interaction between RANKL and RANK. The experiment for the effect of pregnancy on gingival health showed greater gingival inflammation and edema during pregnancy, despite similar plaque index. There should be many factors affecting the periodontal health in pregnancy. In this experiment, we examined the direct effects of sex hormones(estrogen and progesterone) on the ODF/OPG expression in human gingival fibroblasts and periodontal ligament cells at the serum concentration of pregnancy. The ratio was high in the 1st trimester of pregnancy by estrogen and in the late 2nd trimester by progesterone. Therefore, the local periodontal destruction might be accelerated by these hormonal effect on the periodontal cells.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.97-108
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• 1993

One of the important initial events required for periodontal regeneration is the attachment and subsequent spreading of periodontal ligament cells on the root surface. The purposes of this study is to investigate the attachment and spreading pattern of human periodontal ligament cell on the surface of glass slides. After establishment of a cell line of the primary cell culture from the periodontal ligament of 1st premolar teeth which were extracted for the purpose of orthodontic treatment, author dispersed the cells at $5{\times}10^3\;cells/ml$ into the each 35mm culture petri-dish containing 2 glass slides. To observe the morphological changes of the cells which attached to the surfaces of glasses at every designed time schedule, author used the inverted phase contrast microscope and scanning electron microscope. During the whole experiment culture condition was at $37^{\circ}C$, 100% Humidity, 5% $CO_2$ gas incubator. The following results were obtained. Periodontal ligament cells showed spherical outline and started to attach to glass surface by basal sytoplasmic extension after 10min in culture. After 30min in culture, periodontal ligament cells were attached to glass surface by well - developed filopodia which protruded from the lamellipodia. The cell surface is covered with bubble-like structures and occasional microvillus can be seen with diffculty among these structures. After 1.5hr in culture, peridontal ligament cells shhowed radially well-spread cytoplasm and the nucleus was centered on its cytoplasm. Unspread central region of the cell was covered with numerous microvilli. The change of cell attachment and spreading pattern was manifest at 6hr in culture. At this time, periodontal ligament cell showed elongated outline and an oval-shaped nucleus. After 12hr in culture, periodontal ligament cells showed more stretched fibroblast-like appearance with polarity. Two long lamellipodia can be seen around the both terminal ends of cells. After 24hr in culture, periodontal ligament cells showed spindle shapes and an oval-shaped nucleus was slanted toward one side of the cell.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.31-40
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• 1999

Many factors may affect periodontal changes during the physiologic conditions of woman(e.g. puberty, menstrual cycle, pregnancy, menopause). Recently many research has focused on the immunological changes of host, but the exact mechanism is not clear. Collagen is a major constituent of periodontium, and collagenase specifically digests the collagen and plays a role in destruction of periodontal tissue. So, I suppose that it participates with the cytokines in the inflammation of gingiva and vascular response during the changes of female sex hormones. Because there are some evidences of the existence of the receptors of estrogen and progesterone in the gingiva, it may be a target tissue of female sex hormones. In this experiment, gingival fibroblast and periodontal ligament cell were cultured in the presence of various concentrations of estrogen or progesterone corresponding to the menstrual cycle and pregnancy. Collagenase activity of the supernatant of culture media was determined by Spectrophotometric collagenase assay. The enzyme activity was calculated by the % decrease of the coated collagen. 1. The estrogen at both concentrations had no effect on the activity of collagenase of the gingival fibroblast. 2. The progesterone had some effect on the collagenase activity of the gingival fibroblast at low and high concentration of menstrual cycle, and elevated the enzyme activity at all range of pregnancy concentrations. 3. In periodontal ligament cells, estrogen elevated the enzyme activity at the early pregnancy concentration and progesterone elevated at the concentration just before menstruation. In this experiment, pregesterone elevated the collagenase activity of gingival fibroblast and periodontal ligament cells. But the mechanism of the up-regulation of the enzyme activity was not confirmed. The more experiments of direct effect of progesterone on gingival at the molecular level(e.g. northern blot analysis) can reveal the exact mechanism.

• The Journal of Korean Medicine
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• v.24 no.3
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• pp.35-44
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• 2003

Objective : This study was performed to evaluate the effects of Palmijihwang-hwan (Baweidehuang-wan) and Obaeja (Galla Rhois) on the regeneration of periodontal tissue. Methods : In this study, we used MC3T3-El cells, such as osteoblast-like cell lines and human periodontal ligament fibroblasts, for experimental material. We separated each type of cells into a control group and an experimental group. In the control group, the cells were cultivated for 48 hours with distilled water and media which contained 10% fetal bovine serum (FBS) and penicillin (l00unit/ml)-streptomycin ($l00{\mu\textrm{g}}/ml$) at $37^{\circ}$ in 5% $CO_2$ gas. In the experimental group, the cells were cultivated for 48 hours with Palmijihwang-hwan extract and Obaeja extract (concentrations $1{\mu\textrm{g}}/ml,{\;}25{\mu\textrm{g}}/ml,{\;}50{\mu\textrm{g}}/ml$) under the same conditions as the control group. Investigating the regeneration of periodontal tissue was performed by evaluating proliferation, the activity of alkaline phosphatase and the synthetic ability of proteins using those cultivated cells by means of microculture tetrazolium (MTT) assay, alkaline phosphatase substrate kit and protein assay kit. Results : 1. In vitro, Palmijihwang-hwan extract increased the proliferation of MC3T3-El cells. 2. In vitro, Obaeja extract increased the activity of alkaline phosphatase and the synthetic ability of protein in MC3T3-El cells and human periodontal ligament fibroblasts depending on Obaeja extract's concentration. Conclusion : Obaeja extract can be developed as a subsidiary medicine for the regeneration of periodontal tissue. Further studies to evaluate the different concentrations the Obaeja extract and clinical trials in vivo are suggested.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.909-922
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• 1997

The purpose of this study was to evaluate the effect of high glucose on prostaglandin E2 production in human gingival fibroblasts and periodontal ligament cells in vitro. In control group, the cells($5{\times}10^4\;cells/ml$) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, 45mg/dl glucose. In experimental groups, glucose was added to the above culture condition at the final glucose concentrations of 100mg/dl(Test group 1), 200mg/dl (Test group 2) and 400mg/dl (Test group 3). Then each group was tested for the cell proliferation rate, protein levels, and prostaglandin E2 production at $\frac{1}{2}$, 1, 2, 5 days. The results were as follows : 1. As glucose concentration increased, cell proliferation rate decreased significantly at 1, 2, 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.01). 2. In human gingival fibroblasts, test group 2 and 3 showed significantly decreased protein levels as compared to control group at 5 days (P<0.01). 3. In human periodontal ligament cells, as glucose concentration increased, protein levels decreased significantly at 2 days and 5 days(P<0.01). 4. Prostaglandin $E_2$ production in human gingival fibroblasts and human periodontal ligament cells significantly increased as glucose concentration increased(P<0.01). results at 5 days showed obvious difference as compared to those at 2 days. From the above results, high glucose appeared to affect cellular activities including cell proliferation rate, protein levels and enhance prostaglandin $E_2$ production. It was assumed that prostaglandin E2 production by high glucose enhances inflammatory reaction and has a toxic effect on human gingival fibroblasts and human periodontal ligament cells. This study suggests that periodontal disease in diabetic patient is related to prostaglandin $E_2$ production.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.109-122
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• 1984

The purpose of this study was to analyze the magnitude and mode of the stress distribution induced in the supporting alveolar bone and periodontal ligament and, to determine the displacement of abutment teeth and telescope denture base by applying chewing force to the telescope denture quantitatively and qualitatively. Two finite element models of telescope denture that were restored the missing mandibular second molar with two abutment teeth which were constructed. In two different models, parallel and tapering type telescope crowns were constructed. These finite element models of two cases used for these experiment were a two-dimensional mesiodistal section of the mandibular second bicuspid and first molar. Chewing force of 25Kg that was devided in the ratio of 45/155 (29%) in bicuspid and 55/155 (35.5%) in molars was applied to telescope denture and abutment teeth respectively. The displacement of the telescope denture base and abutment teeth and the stress distribution in the periodontal ligament and alveolar bone were analized to investigate the influence of chewing force acting on the telescope denture and abutment teeth. The results were as follows: 1. Abutment teeth displaced mesially and the magnitude of displacement of abutment teeth in vertical direction were more than that of horizontal direction in two cases. The displacement of abutment teeth on the telescope denture treated with tapering type telescope crown were less than that of the parallel type crown. 2. The displacement of the telescope denture base that were treated with parallel type telescope crown were less than that of treated with tapering type telescope crown. 3. The stress induced in the alveolar bone and periodontal ligament on abutment teeth that treated with parallel type telescope crown were more than that of treated with tapering type telescope crown and more stress induced in the alveolar bone than in the periodontal ligament. 4. In the telescope denture, the magnitude of displacement of abutment teeth and stress induced in the periodontal ligament and alveolar bone were within physiologic limit.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.27-37
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• 2006

Although the main purpose of periodontal treatment to regenerate is the complete regeneration of periodontal tissue due to periodontal disease, most of the treatment cannot meet such purpose because healing by long epithelial junction. Therefore, diverse materials of resorbable and non-resorbable have been used to regenerate the periodontal tissue. Due to high risk of exposure and necessity of secondary surgical procedure when using non-resorbable membrane, guided tissue regeneration using the resorbable membrane has gain popularity, recently. However, present resorbable membrane has the disadvantage of not having sufficient time to regenerate date to the difference of resorption rate according to surgical site. Meanwhile, other than the structure stability and facile manipulation, acellular dermal matrix has been reported to be a possible scaffold for cellular proliferation due to rapid revascularization and favorable physical properties for cellular attachment and proliferation. The purpose of this study is to estimate the influence of acellular dermal matrix on periodontal ligament, cementum and alveolar bone when acellular dermal matrix is implanted to 1-wall alveolar bone defect. 4 dogs of 12 to 16 month old irrelevant to sex , which below 15Kg of body weight, has been used in this study. ADM has been used for the material of guided tissue regeneration. The 3rd premolar of the lower jaw was extracted bilaterally and awaited for self-healing. subsequently buccal and lingual flap was elevated to form one wall intrabony defect with the depth and width of 4mm on the distal surface of 2nd premolar and the mesial surface of 4th premolar. After the removal of periodontal ligament by root planing. notch was formed on the basal position. Following the root surface treatment, while the control group had the flap sutured without any treatment on surgically induced intrabony defect. Following the root surface treatment, the flap of intrabony defect was sutured with the ADM inserted while the control group sutured without any insertion. The histologic specimen was observed after 4 and 8 weeks of treatment. The control group was partially regenerated by periodontal ligament, new cementum and new alveolar bone. the level of regeneration is not reached on the previous formed notch. but, experimental group was fully regenerated by functionally oriented periodontal ligament fiber. new cementum and new alveolar bone. In conclusion, we think that ADM seems to be used by scaffold for periodontal ligament cells and the matrix is expected to use on guided tissue regeneration.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.121-136
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• 2001

This study was performed to analyse the expression of VEGF and it's receptor(VEGFR) in the tension side of the periodontal ligament following orthodontic tooth movement. Upper first molars of Sprague-Dawley rats were moved medially using closed coil spring for 1, 2, 24 hours and 3, 7, 14 days. H&E staining, immunohistochemical staining and in situ hybridization methods were used to analyse the change of the expression of VEGF and VEGFR. The results from this study were as follows : 1. Following tensional force, periodontal ligament showed elongation of fibers, compression and congestion of vessels and regional hemorrhage. These tissue changes were recovered within 3 days of force application. New bone formation was seen after 3 days of force application and continued for the remaining experimental periods. 2. Following tensional force, VEGF and VEGF mRNA expression was increased in the periodontal ligament cells, osteoblasts and cementoblasts. This change was followed by increased vasculature in the periodontal ligament. 3. After 3 days of tensional force, VEGF and VEGF mRNA expression was confined mainly to the osteopaths and the periodontal ligament cells adjacent to the alveolar bone. After 2 weeks of force application, VEGF and VEGF mRNA expression was reduced to the level of control sample. 4. VEGFRs(Flt-1, Flk-1) showed similar expression pattern and it's expression was mainly seen in the endothelial cells and osteoblasts. Following tensional force VEGFR expression was increased in the endothelial cells and osteoblasts. In conclusion, in the tension side of the penodontal ligament, ligament cells, osteoblast and cementoblast showed increased expression of VEGF & VEGF mRNA. It preceded the increase of vasculature and new bone formation. The increased expression of VEGF mRNA in cementoblast may induce periodontal vessels, which distribute mainly the bone side half of periodontal ligament, grow in the direction of tensional force. Increased expression of VEGFR & VEGFR mRNA not only in endothelial cell but in osteoblast, osteocyte and periodontal cells showed VEGF acts not only in paracrine manner but in autocrine one.

• Molecules and Cells
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• v.40 no.8
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• pp.550-557
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• 2017

The periodontal ligament (PDL) is the connective tissue between tooth root and alveolar bone containing mesenchymal stem cells (MSC). It has been suggested that human periodontal ligament stem cells (hPDLSCs) differentiate into osteo/cementoblast and ligament progenitor cells. The periodontitis is a representative oral disease where the PDL tissue is collapsed, and regeneration of this tissue is important in periodontitis therapy. Fibroblast growth factor-2 (FGF-2) stimulates proliferation and differentiation of fibroblastic MSCs into various cell lineages. We evaluated the dose efficacy of FGF-2 for cytodifferentiation of hPDLSCs into ligament progenitor. The fibrous morphology was highly stimulated even at low FGF-2 concentrations, and the expression of teno/ligamentogenic markers, scleraxis and tenomodulin in hPDLSCs increased in a dose dependent manner of FGF-2. In contrast, expression of the osteo/cementogenic markers decreased, suggesting that FGF-2 might induce and maintain the ligamentogenic potential of hPDLSCs. Although the stimulation of tenocytic maturation by $TGF-{\beta}1$ was diminished by FGF-2, the inhibition of the expression of early ligamentogenic marker by $TGF-{\beta}1$ was redeemed by FGF-2 treatment. The stimulating effect of BMPs on osteo/cementogenesis was apparently suppressed by FGF-2. These results indicate that FGF-2 predominantly differentiates the hPDLSCs into teno/ligamentogenesis, and has an antagonistic effect on the hard tissue differentiation induced by BMP-2 and BMP-4.