• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.53-64
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• 2007

The aim of this study was to examine the possibility of periodontal ligament regeneration when autotransplantation was used by the periodontal ligament fibroblasts cultured on the acellular dermal matrix in teeth without a periodontal ligament. One minipig was used in this study. The mandibular and maxillary permanent incisors were ex-tracted for the culture of the periodontal ligament cells. The roots of the unextracted teeth were classified into a positive control group, in which the normal periodontal ligament was preserved. The roots of the extracted teeth were divided into the following two groups: The negative control group, in which the periodontal ligament had been removed and the acellular dermal matrix was not applied; and an experimental group, in which the periodontal ligament had been removed and periodontal ligament fibroblast cultured on an acellular dermal matrix was applied. The prepared teeth were transplanted, and completely submerged using physical barrier membranes. The animal was sacrificed 4 weeks after the autotransplant. The transplanted teeth were examined histologically. In this study, the periodontal ligament was normal in the positive control group, and ankylosis was discovered on the denuded root surface in the negative control group. Periodontal ligament-like connective tissue was found adjacent to the denuded root and the new cementum-like layer of hard tissue was formed in the experimental group. These results suggest that the periodontal ligament fibroblasts cultured on the acellular dermal matrix may play a role in regenerating the periodontal ligament-like tissue with new cememtum-like tissue formation.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.176-187
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• 1996

The ability of fibroblasts attached to teeth is paramount important in reestablishing the lost connective tissue attachment after periodontal therapy. The migration and proliferation of periodontal ligament cells are desired goal of periodontal regeneration therapy. PDGF is well known to regulate the cell activity of mesenchymal origin cell. Tobacco contains a complex mixture of substance including nicotine, various nitrosamines, trace elements, and variety of poorly characterized substances. Human gingival fibroblasts and periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Cultured human gingival fibroblasts and periodontal ligament cells in vitro were treated with PDGF, nicotine in time dependent manner. Cellular activities were determined by MTT assay. The purpose of this study was to determine the effects of Nicotine and PDGF, respectively and the effect of PDGF presence of nicotine on human gingival fibroblasts and periodontal ligament cells. The results were as follows : 1. In the cell activities of human gingival fibroblasts and periodontal ligament cells were similar or decreased to control value at 1st day. At 2nd day, cellular activities of both group were increased to control value. At 3rd day, cellular activities of both group were returned to the control value. 2. In the cell activities of PDGF on human gingival fibroblasts and periodontal ligament cells, cell activities significantly increase from control group on periodontal ligament cells compared to gingival fibroblast group at 3rd day. 3. In the cell activities of PDGF and nicotine combined application on human gingival fibroblasts and periodontal ligament cells, it seems likely that the nicotinic effect of gingival fibroblasts were higher than periodontal ligament cells and the PDGF effect of periodontal ligament cells were higher than gingival fibroblasts. This results suggested that PDGF might stimulate the selective growth on periodontal ligament cells.

• Imaging Science in Dentistry
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• v.46 no.4
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• pp.229-237
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• 2016

Purpose: The aim of this article is to review a group of lesions associated with periodontal ligament (PDL) widening. Materials and Methods: An electronic search was performed using specialized databases such as Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus to find relevant studies by using keywords such as "periodontium", "periodontal ligament", "periodontal ligament space", "widened periodontal ligament", and "periodontal ligament widening". Results: Out of nearly 200 articles, about 60 were broadly relevant to the topic. Ultimately, 47 articles closely related to the topic of interest were reviewed. When the relevant data were compiled, the following 10 entities were identified: occlusal/orthodontic trauma, periodontal disease/periodontitis, pulpo-periapical lesions, osteosarcoma, chondrosarcoma, non-Hodgkin lymphoma, progressive systemic sclerosis, radiation-induced bone defect, bisphosphonate-related osteonecrosis, and osteomyelitis. Conclusion: Although PDL widening may be encountered by many dentists during their routine daily procedures, the clinician should consider some serious related conditions as well.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.623-634
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• 1995

Periodontitis is characterized by gingival inflammation and results in periodontal pocket formation with loss of the supporting alveolar bone and connective tissue around the teeth. Therapeutic modalities should therefore aim not only at eliminating the gingival inflammatory process and preventing the progression of periodontal disease but also at reestablishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, progenitor cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Likewise, progenitor bone cells must also migrate, proliferate, and mature in conjunction with the regenerating periodontal ligament. Significant advances have been made during the last decade in understanding the factors controlling the migration, attachment and proliferation of cells. A group of naturally occuring molecules known as polypeptide growth factors in conjunction with certain matrix proteins are key regulators of these biological events. Of these, the fibroblast growth factor(FGF), platelet-derived growth factor(PDGF) , insulin like growth factor(CIGFs), transforming growth factor(TGFs), epidermal growth factor(EGF) and bone morphogenetic growth factor(BMPs) apper to have an important role in periodontal wound healing. The purpose of this study was to determine the effects of BMP on periodontal ligament cells. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Cultured periodontal ligament cells were treated with BMP. Cellular activities were determined by MTT(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and ALP(alkaline phosphatase) activity. The results were as follows ; Regardless of cultured time, cellular activities were stimulated by BMP. Also, BMP greatly increased alkaline phosphatase(ALP) in periodontal ligament cells. These results suggest that BMP not only have no cytotoxic effect on periodontal ligament cells, but also have osteogenic stimulatory effect on periodontal ligament cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.455-463
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• 2007

The present study was designed to evaluate effects of the commonly used NSAIDs(acetaminophen, aspirin, and ibuprofen) on human periodontal ligament cells. Human periodontal ligament cells were grown from a cell line provided by Kyungpook National University. Effects of NSAIDs on the proliferation of human periodontal ligament cells were assessed using MTT assays. And then $PGE_2$ concentrations were determined by ELISA and the changes of cellular configuration were found by electron micrograph. The results were as follows; 1. The MTT assay demonstrated that the commonly used NSAIDs(acetaminophen, aspirin, and ibuprofen) had not significant cytotoxic effect on human periodontal ligament cells. 2. NSAIDs inhibited the $PGE_2$ synthesis of human periodontal ligament cells compared with the control group. These inhibitory effects had no significant differences with NSAID type and concentration. 3. Electron micrographs of human periodontal ligament cells treated with NSAIDs showed more narrow and irregular shape.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.163-180
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• 2001

The aim of this study was to evaluate the effects of chitosan coating on the attachment, proliferation, functional and morphological change of periodontal ligament cells. Primary human periodontal ligament cells were cultured in dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. In experimental group, cells of 4th to 7th passage were inoculated in the multiwell plates coated with chitosan in concentration of 0.22, 0.2, and $2mg/m{\ell}$. Cell counting and MTT assay were done after 0.5, 1.5, 3, 6 and 24 hours of incubation to evaluate the cell attachment, and then after 2 and 7 days of culture to evaluate the cell proliferation. The alkaline phosphatase activity was measured after 4 and 7 days of culture and the ability to produce mineralized modules was evaluated after 21 days of culture. The results were as follows : 1. The morphology of periodontal ligament cells on the chitosan coating was round or spheric. Round cells were aggregated after 6 hours of culture. Aggregated cells on the chitosan coated surface showed nodule-like appearance after 24 hours of culture and not achieved confluency at 7 days. 2. During early period of culture, the attachment of periodontal ligament cells were inhibited by chitosan coating. Inhibition of cell attachment tended to increase with the concentration of chitosan. 3. At the chitosan concentration of 0.02 and $0.2mg/m{\ell}$, periodontal ligament cells were more rapidly proliferated at 7 days, compared to the control group. At the concentration of $2mg/m{\ell}$, the proliferation of periodontal ligament cells was inhibitied(p<0.01). 4. Alkaline phosphatase activity of periodontal ligament cells was increased in chitosan coated group, especially at the concentration of $0.02mg/m{\ell}$after 4 days of culture.5. Periodontal ligament cells produced mineralized nodules on chitosan coated wells without the addition of mineralized nodule forming materials (ascorbic acid, ${\beta}-glycerophosphat$, dexamethasone). With the addition of mineralized nodule forming materials, periodontal ligament cells produced more mineralized nodules at the concentration of $0.02mg/m{\ell}$, compared to the control. In summary, the attachment, proliferation, cell activity, and alkaline phosphatase activity of periodontal ligament cells depended on the concentration of coated chitosan. Chitosan stimulated mineralized nodule formation by periodontal ligament cells. At the appropriate concentration($0.02mg/m{\ell}$), chitosan could increase alkaline phosphatase activity and stimulate the formation of mineralized nodule by periodontal ligament cells. These results suggest that chitosan can be used as an adjunct for bone graft material, and the matrix of tissue engineering for periodontal regeneration, especially bone regeneration.

• Journal of Periodontal and Implant Science
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• v.27 no.2
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• pp.291-303
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• 1997

Periodontal ligament cells may have a role in the regulation of hard and soft periodontal tissues, but their specific function has not yet to be determined. To evaluate further their role in periodontal regeneration, they were examined for osteoblast-like behavior. Periodontal ligament cells and gingival fibroblasts were primarily cultured from extracted premolar with non-periodontal diseases. Cells were cultured with DMEM at $37^{\circ}C$, 5% $CO_2$, 100% humidity incubator, and as a measure of cell characterization, it was examined that the morphology, alkaline phosphatase activity, collagen synthesis, and immunocytochemistry for osteonectin, osteocalcin, and collagen type I. Healthy periodontal ligament cells has more osteoblastic-like cell property in alkaline phosphatase activity. and collagen synthesis than gingival fibroblast. Immunocytochemistry localization explained that calcitonin were expressed in periodontal ligament cells only, and osteonectin and type I collagen were produced in both cells simultaneously. This results indicate that the growth characteristics of periodontal ligament cells and gingival fibroblasts exhibit some differences in proliferative rates and biochemical synthesis. The differences may help to calrify the role such cells play in the regenearation of periodontal tissues.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.367-375
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• 2004

As the periodontal ligament cells show similar phenotype with osteoblasts, periodontal ligament cells are thought to play an important role in alveolar bone remodeling. According to recent studies, receptor activation of nuclear factor $^{\kappa}B$ ligand (RANKL) and osteoprotegerin (OPG) are expressed in periodontal ligament cells during tooth movement. Also periodontal ligament cells is known to play an important role in the progression of periodontal disease. This study was designed how the expression of RANKL and OPG in periodontal ligament cells was regulated by IL-1 ${\beta}in$ the concentration of $0.01{\sim}10$ ng/ml. The results are as follows; 1. Periodontal ligament cells which stimulated by 1L-1 ${\beta}$ increased soluble RANKL synthesis by dose-dependent pattern in the concentration of $0.01{\sim}10$ ng/ml. 2. 1L-1 ${\beta}$ induced mRANKL expression in dose-dependent manner in the concentration of $0.01{\sim}5$ ng/ml. 3. mOPG expression was not to be influenced by 1L-1 ${\beta}$. These results suggested that rat periodontal ligament cells could regulate osteoclastogenesis by stimulation of production of RANKL.

• International Journal of Oral Biology
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• v.38 no.3
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• pp.87-92
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• 2013

Periodontal inflammation increases the risk of tooth loss, particularly in cases where there is an associated loss of alveolar bone and periodontal ligament (PDL). Histological and morphometric evaluation of periodontal inflammation is difficult. Especially, the lengths of the periodontal ligament and interdental alveolar bone space have not been quantified. A quantitative imaging procedure applicable to an animal model would be an important clinical study. The purpose of this study was to quantify the loss of alveolar bone and periodontal ligament by evaluation with micro-computed tomography (micro-CT). Another purpose was to investigate differences in infections with systemic E. coli LPS and TNF-${\alpha}$ on E. coli lipopolysaccharide (LPS) in loss of alveolar bone and periodontal ligament model on mice. This study showed that linear measurements of alveolar bone loss were represented with an increasing trend of the periodontal ligament length and interdental alveolar process space. The effects of systemic E. coli LPS and TNF-${\alpha}$ on an E. coli LPS-induced periodontitis mice model were investigated in this research. Loss of periodontal ligament and alveolar bone were evaluated by micro-computed tomography (micro-CT) and calculated by the two- and three dimensional microstructure morphometric parameters. Also, there was a significantly increasing trend of the interdental alveolar process space in E. coli LPS and TNF-${\alpha}$ on E. coli LPS compared to PBS. And E. coli LPS and TNF-${\alpha}$ on E. coli LPS had a slightly increasing trend of the periodontal ligament length. The increasing trend of TNF-${\alpha}$ on the LPS-induced mice model in this experiment supports the previous studies on the contribution of periodontal diseases in the pathogenesis of systemic diseases. Also, our findings offer a unique model for the study of the role of LPS-induced TNF-${\alpha}$ in systemic and chronic local inflammatory processes and inflammatory diseases. In this study, we performed rapidly quantification of the periodontal inflammatory processes and periodontal bone loss using micro-computed tomography (micro-CT) in mice.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.188-201
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• 1996

One of the initial events required for periodontal regeneration is the attachment, spreading and proliferation of fibroblasts at the healing sites. These have been reported that minocycline stimulates the attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the proliferation of periodontal ligament cells. The purpose of this study was to evaluate and confirm the effect of minocycline and $TGF-{\beta}1$ on human gingival fibroblasts and periodontal ligament cells. That gingival fibroblasts and periodontal ligament cells used in this study were obtained from the explants of healthy periodontal ligaments and gingival tissues of extracted 3rd molars or premolar teeth extracted from the patients with orthodontic treatment. The cells were cultured in ${\alpha}-MEM$(minimal essential medium) supplemented with antibiotics and FBS(fetal bovine serum) at $37^{\circ}C$ in a humidified atmosphere of 5% carbon dioxide-95% air. Cells were used between the 5th to 8th passage in this study. The attachment and activity of both cells were evaluated by MTT assay. The results were as follows: 1. Maximum gingival fibroblast attachment was seen at a $50{\mu}g/ml$ dose of minocycline, while maximum periodontal ligament cell attachment was seen at a $100{\mu}g/ml$, and exposure of both cells to minocycline above maximal attachment dose results in a decline from maximum attachment. 2. The activity values of both cells tested minocycline were below to the control activity values at all concentrations. 3. The attachment values of both cells tested $TGF-{\beta}1$ were below or similar to control attachment values. On the above the findings, minocycline stimulated the cell attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the cell activity of periodontal ligament cells.