• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.3
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• pp.211-220
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• 2007

Objective: In organotypic culture of immortalized human oral keratinocytes (IHOK), the change of the growth and differentiation was investigated according to the fibroblast type and the involvement of mitogen-activated protein (MAP) kinase. Materials & Methods: IHOK was cultured three dimensionally with gingival fibroblast (GF), dermal fibroblast (DF) and immortalized gingival fibroblast (IGF). We characterized biologic properties of three dimensionally reconstructed IHOK by histological, immunohistochemical, and Western blot analysis. We also investigated whether MAP kinase pathway was involved in epithelial-mesenchymal interaction by Western blot analysis. Results: The best condition of three dimensionally cultured IHOK was the dermal equivalent consisting of type I collagen and IGF. IGF increased the expression of more proliferating cell nuclear antigen (PCNA), involucrin than GF and DF in response to co-culture with IHOK. Extracellularly regulated kinase (ERK) pathway was activated in organotypic co-culture with IGF. Conclusion: The organotypic co-culture of IHOK with dermal equivalent consisting of type I collagen and IGF resulted in excellent morphologic and immunohistochemical characteristics and involved ERK pathway. The epithelial-mesenchymal interaction was activated according to the fibroblast type.

• Journal of Korean society of Dental Hygiene
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• v.14 no.1
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• pp.95-100
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• 2014

Objectives : The purpose of the present study was to investigate the effect of bamboo charcoal on Streptococcus mutans which is one of the most important causative agents of dental caries. Methods : S. mutans was incubated with or without bamboo charcoal and then changes were observed in its cell viability and antibacterial effect. Oral epithelial cells viabillity(human gingival fibroblast, HGF) was performed using MTT assay. Antibacterial effect was analyzed using a dilution plating method and agar diffusion method. Results : Oral epithelial cells, human gingival fibroblast (HGF) showed a tendency to increase in bamboo charcoal treatment solution concentrations(0.5, 1, 2, 3, 5, 10%). The bamboo charcoal had an antibacterial effect on S. mutans. Antibacterial effect of bamboo charcoal for the bacterium was 58%. Charcoal concentration of 2% and 5% in the inhibition zone showed a minimal growth, but the concentration of 10% bamboo charcoal in inhibition zone revealed a conspicuous antibacterial activity. Conclusions : Overall results suggested that the bamboo charcoal proved to be bactericidal effect on S. mutans.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.349-357
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• 1997

Epidermal growth factor(EGF), a single chain polypeptide of 53 amino acids with a molecular weight of 6,045 Da, was first isolated from the male mouse submandibular glands. EGF stimulates cellular proliferation and differentiation in several tissues and accelerates the rate of wound healing. EGF is bound to the specific receptor(EGFR) on the cell membrane of its target cell. EGFR is a transmembrane glycoprotein with a molecular weight of 170,000 Da and is detectable on a large variety of cell types and tissues. The authors investigated the expression of EGFR in the normal and inflamed human gingival epithelium to study the role of EGFR in the inflammation of the gingival epithelium, and the expression of EGFR in the dental follicle by using in situ mRNA hybridization and immunohistochenistry. The results weree as follows : 1. The expression of EGFR mRNA in the normal gingival epithelium on in situ mRNA hybridization was mainly localized on the basal cell layer, and the spinous layer was weakly positive The granular and cornified layers were negative 2. The expression of EGFR protein in the normal gingival epithelium on inmunohistochemistry was localized on the cornified and granular layers, and the spinous layer was weakly positive. The basal cell layer was completely negative 3. The expression of EGFR mRNA in the inflamed gingival epithelium on in situ mRNA hybridization was evenly and homogeneously distributed in the whole layers of the gingival epithelium except the cornified layer. The staining intensity appeared to increase progressively from the basal cell layer to the cornified layer. 4. The expression of EGFR protein in the inflamed gingival epithelium on immunohistochemistry was evenly and homogeneously distributed in the whole layers of the gingival epithelium. The staining intensity appeared to increase progressively from the cornified layer to the basal cell layer. 5. Strong positive reaction was seen in the epithelial cell rests of Malassez, whereas only background staining was seen in other cells of the dental follicle. In conclusion, the up-regulation of EGFR in the inflamed gingival epithelium and the high amounts of EGFR in the epthelial cell rests of Malassez in the dental follicle can be regarded as responses to the possible damages to the oral environment to maintain the homeostatic conditions.

• Journal of dental hygiene science
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• v.18 no.2
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• pp.76-84
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• 2018

Wet wipes are being increasingly used because of their convenience. Particularly, oral wet wipes are useful for regular cleaning of a baby's mouth after birth. Therefore, the consumption of oral wet wipes has increased over the past few years and a variety of products are commercially available. However, product information on safety is not sufficiently provided and still raises doubts regarding adverse effects. To confirm the safety of wet wipes as an oral hygiene item and provide information for their use, we investigated the cytotoxicity of oral wet wipes and verified the underlying mechanism. The anti-bacterial effect of oral wet wipes was analyzed using the disk diffusion method. The cytotoxic effects of oral wet wipes were observed based on morphological changes using microscopy and determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in gingival epithelial cells and gingival fibroblasts. Evaluation of apoptosis by oral wet wipes was explored using propidium iodide flow cytometric analysis and a terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) assay. Apoptosis-related molecules were also analyzed using western blotting. Five types of oral wet wipes were tested, and two products from Fisher-Price and Dr. Kennedy revealed strong cytotoxic effects on gingiva epithelial cells and gingiva fibroblasts, although they also showed intense anti-bacterial effects on oral bacteria. Cell cycle arrest in the G2/M phase and apoptosis were observed based on treatment of extracts from Fisher-Price and Dr. KENNEDY. Relatively high TUNEL levels, reduction of proliferating cell nuclear antigen and cyclin-dependent kinase 4 expression, and fragmentation of poly (ADP-ribose) polymerase were also elucidated. These results suggest that commercial oral wet wipes could exert cytotoxic influences on oral tissue, although there are anti-bacterial effects, and careful attention is required, especially for infants and toddlers.

• Journal of Periodontal and Implant Science
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• v.49 no.5
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• pp.270-286
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• 2019

Purpose: Despite the well-known anti-inflammatory effects of vitamin D in periodontal health, its mechanism has not been fully elucidated. In the present study, the effect of vitamin D on strengthening E-cadherin junctions (ECJs) was explored in human gingival keratinocytes (HGKs). ECJs are the major type of intercellular junction within the junctional epithelium, where loose intercellular junctions develop and microbial invasion primarily occurs. Methods: HOK-16B cells, an immortalized normal human gingival cell line, were used for the study. To mimic the inflammatory environment, cells were treated with tumor necrosis factor-alpha ($TNF-{\alpha}$). Matrix metalloproteinases (MMPs) in the culture medium were assessed by an MMP antibody microarray and gelatin zymography. The expression of various molecules was investigated using western blotting. The extent of ECJ development was evaluated by comparing the average relative extent of the ECJs around the periphery of each cell after immunocytochemical E-cadherin staining. Vitamin D receptor (VDR) expression was examined via immunohistochemical analysis. Results: $TNF-{\alpha}$ downregulated the development of the ECJs of the HGKs. Dissociation of the ECJs by $TNF-{\alpha}$ was accompanied by the upregulation of MMP-9 production and suppressed by a specific MMP-9 inhibitor, Bay 11-7082. Exogenous MMP-9 decreased the development of ECJs. Vitamin D reduced the production of MMP-9 and attenuated the breakdown of ECJs in the HGKs treated with $TNF-{\alpha}$. In addition, vitamin D downregulated $TNF-{\alpha}$-induced nuclear factor kappa B ($NF-{\kappa}B$) signaling in the HGKs. VDR was expressed in the gingival epithelium, including the junctional epithelium. Conclusions: These results suggest that vitamin D may avert $TNF-{\alpha}$-induced downregulation of the development of ECJs in HGKs by decreasing the production of MMP-9, which was upregulated by $TNF-{\alpha}$. Vitamin D may reinforce ECJs by downregulating $NF-{\kappa}B$ signaling, which is upregulated by $TNF-{\alpha}$. Strengthening the epithelial barrier may be a way for vitamin D to protect the periodontium from bacterial invasion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.369-372
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• 2000

The purpose of this study was to investigate the distribution pattern of CGRP immunoreactive nerve fibers in the healing mucosa of extracion wound. Maxillary 1st molars of rats were extracted. All extraction sites and adjacent tissues of 3 groups of rats(1-week, 2-week and 4-week groups) were removed en bloc and processed for immunostaining and were subjected to light microscopic examination. The results obtained were as follows; In 1-week group, there was no difference in the distribution pattern of CGRP immunoreactive nerve fiber between epithelial margin adjacent to extraction socket and normal gingival epithelium. In 2-week group, some CGRP-immunoreactive nerve fibers were seen in epithelial layer. In 4-week group, many intercellular CGRP immunoreactive nerve fibers were abundant in all layers of immature epithelium characterized by scab on the mucosa and thick keratinized cell layer with irregular surface. Intraepithelial CGRP immunoreactive nerve fibers were reduced to normal level in adjacent mature epithelium. These results suggest that density of CGRP immunoreactive nerve fibers are increased transiently in epithelium during reepithelialization process and CGRP released from these nerve fibers may play an important role in the reepithelialization in the wound healing.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.138-145
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• 2015

PURPOSE. The objective of this study was to conduct an in vitro comparative evaluation of polished and laser-dimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS. Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had $5-{\mu}m$ dimples at $10-{\mu}m$ intervals, and SM30 (n=16) had $5-{\mu}m$ dimples at $25-{\mu}m$ intervals in a $2{\times}4mm^2$ area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS. The adhesion strength of epithelial cells was higher on Ti surfaces with $5-{\mu}m$ laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION. These findings demonstrate that laser dimpling may contribute to improving the peri-implant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.145-158
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• 1993

The oral microbiota such as P. gingivalis, P. intermedia and A. actinomycetemcomitans play a primary role in the initiation and progression of the periodontal disease. The purpose of this study was to evaluate the antimicrobial effects and inhibitory effects of honokiol and magnolol on the bacterial collagenase activity, cytotoxicity and cytokine production of periodontopathic microorganisms. The antimicrobial activities of honokiol and magnolol was evaluted with minimum inhibition concentration. Honokiol was more active than magnolol, but less than chlorhexidine on antimicrobial activity. The inhibitory effects of magnolol and honokiol on the collagenolytic activity and cytotoxicity were evaluated using a Collagenokit CLN-100 and rapid colorimetric assay (MTT method) for cellular growth and survival of gingival fibroblast and periodontalligament cell and $[^3H]-thymidine$ incorporation for the gingival epithelial cell. The inhibitory effects on the collagenolytic activity was the highest in chlorhexidine, and the lowest in magnolol. Magnolol had the lowest cytotoxic effect and chlorhexidine had the highest. The inhibitory effects on cytokine production was evaluated using $interleukin-1{\beta}$ ELISA kit (Cistron Biotech.), IL-6, $TNF-{\alpha}$ ELISA kit (Genzyme) and inhibitory effects were higher than bacterial LPS and there is no difference among the honokiol, magnolol and chlorhexidine. From these results, the antimicrobial and antienzymatic activities of honokiol and magnolol were seemed to inhibit bacterial growth and enzyme activities with lesser cytotoxic activities. Therefore, it was suggested that honokiol and magnolol are very effective antimicrobial agents on periodontal pathogens.

• Carbon letters
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• v.13 no.3
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• pp.139-150
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• 2012

Poly-L-lactic acid (PLLA), PLLA/hydroxyapatite (HA), PLLA/multiwalled carbon nanotubes (MWNTs)/HA, PLLA/trifluoroethanol (TFE), PLLA/gelatin, and carbon nanofibers (CNFs)/${\beta}$-tricalcium phosphate (${\beta}$-TCP) composite membranes (scaffolds) were fabricated by electrospinning and their morphologies, and mechanical properties were characterized for use in bone tissue regeneration/guided tissue regeneration. MWNTs and HA nanoparticles were well distributed in the membranes and the degradation characteristics were improved. PLLA/MWNTs/HA membranes enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion of gingival epithelial cells by 30%. Osteoblast-like MG-63 cells on the randomly fiber oriented PLLA/TEF membrane showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel fiber oriented membrane. Classical supersaturated simulated body fluids were modified by $CO_2$ bubbling and applied to promote the biomineralization of the PLLA/gelatin membrane; this resulted in predictions of bone bonding bioactivity of the substrates. The ${\beta}$-TCP membranes exhibit good biocompatibility, have an effect on PDLC growth comparable to that of pure CNF membrane, and can be applied as scaffolds for bone tissue regeneration.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.109-116
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• 2011

Periodontitis results from the activation of host immune and inflammatory defense responses to subgingival plaque bacteria, most of which are gram-negative rods with lipopoly-saccharides (LPSs) in their cell walls. LPSs have been known to induce proinflammatory responses and recently it was reported also that they induce the expression of microRNAs (miRNAs) in host cells. In our current study therefore, we aimed to examine and compare the miRNA expression patterns induced by the LPSs of major periodontopathogens in the human gingival epithelial cell line, Ca9-22. The cells were treated with 1 ${\mu}g$/ml of E. coli (Ec) LPS or 5 ${\mu}g$/ml of an LPS preparations from four periodontopathogens Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), and Fusobacterium nucleatum (Fn) for 24 h. After small RNA extraction from the treated cells, miRNA microarray analysis was carried out and characteristic expression profiles were observed. Fn LPS most actively induced miRNAs related to inflammation, followed by Aa LPS, Pi LPS, and Ec LPS. In contrast, Pg LPS only weakly activated miRNAs related to inflammation. Among the miRNAs induced by each LPS, miR-875-3p, miR-449b, and miR-520d-3p were found to be commonly up-regulated by all five LPS preparations, although at different levels. When we further compared the miRNA expression patterns induced by each LPS, Ec LPS and Pi LPS were the most similar although Fn LPS and Aa LPS also induced a similar miRNA expression pattern. In contrast, the miRNA profile induced by Pg LPS was quite distinctive compared with the other bacteria. In conclusion, miR-875-3p, miR-449b, and miR-520d-3p miRNAs are potential targets for the diagnosis and treatment of periodontal inflammation induced by subgingival plaque biofilms. Furthermore, the observations in our current study provide new insights into the inflammatory miRNA response to periodontitis.