• International Journal of Oral Biology
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• 제37권3호
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• pp.137-145
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• 2012

Aggregatibacter actinomycetemcomitans is the most important etiologic agent of aggressive periodontitis and can interact with endothelial cells. Monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) are chemokines, playing important roles in periodontal pathogenesis. In our current study, the effects of A. actinomycetemcomitans on the production of MCP-1 and IL-8 by human umbilical vein endothelial cells (HUVEC) were investigated. A. actinomycetemcomitans strongly induced the gene expression and protein release of both MCP-1 and IL-8 in a dose- and time-dependent manner. Dead A. actinomycetemcomitans cells were as effective as live bacteria in this induction. Treatment of HUVEC with cytochalasin D, an inhibitor of endocytosis, did not affect the mRNA up-regulation of MCP-1 and IL-8 by A. actinomycetemcomitans. However, genistein, an inhibitor of protein tyrosine kinases, substantially inhibited the MCP-1 and IL-8 production by A. actinomycetemcomitans, whereas pharmacological inhibition of each of three members of mitogen-activated protein (MAP) kinase family had little effect. Furthermore, gel shift assays showed that A. actinomycetemcomitans induces a biphasic activation (early at 1-2 h and late at 8-16 h) of nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and an early brief activation (0.5-2 h) of activator protein-1 (AP-1). Activation of canonical NF-${\kappa}B$ pathway ($I{\kappa}B$ kinase activation and $I{\kappa}B-{\alpha}$ degradation) was also demonstrated in these experiments. Although lipopolysaccharide from A. actinomycetemcomitans also induced NF-${\kappa}B$ activation, this activation profile over time differed from that of live A. actinomycetemcomitans. These results suggest that the expression of MCP-1 and IL-8 is potently increased by A. actinomycetemcomitans in endothelial cells, and that the viability of A. actinomycetemcomitans and bacterial internalization are not required for this effect, whereas the activation of protein tyrosine kinase(s), NF-${\kappa}B$, and AP-1 appears to play important roles. The secretion of high levels of MCP-1 and IL-8 resulting from interactions of A. actinomycetemcomitans with endothelial cells may thus contribute to the pathogenesis of aggressive periodontitis.

• International Journal of Oral Biology
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• 제38권1호
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• pp.29-36
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• 2013

Mitis group streptococci (MGS) were classified based on the nucleotide sequences 16S rRNA gene (16S rDNA) and comprised 13 Streptococcus species. However, 16S rDNA homogeneity among MGS was too high to discriminate between clinical strains at the species level, notably between Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, and Streptococcus pseudopneumoniae. The purpose of this study was to discriminate between 37 strains of MGS isolated from Korean oral cavities using phylogenetic analysis of the DNA-dependant RNA polymerase beta-subunit gene (rpoB). 16S rDNA and rpoB from clinical strains of MGS were sequenced using the dideoxy chain termination method and analyzed using MEGA version 5 software. The resulting phylogenetic data showed that the rpoB sequences could delineate clinical strains of MGS at the species level. Phylogenetic analysis of rpoB is therefore a useful approach for identifying MGS at the species level.

• International Journal of Oral Biology
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• 제41권1호
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• pp.39-43
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• 2016

Dental caries, the most common oral disease, is a multifactorial disease caused by interactions among bacteria within the dental plaque, food, and saliva, resulting in tooth destruction. Streptococcus mutans has been strongly implicated as the causative organism in dental caries and is frequently isolated from human dental plaque. Photodynamic therapy (PDT) is a technique that involves the activation of photosensitizer by light in the presence of tissue oxygen, resulting in the production of reactive radicals capable of inducing cell death. Postantibiotic effect (PAE) is defined as the duration of suppressed bacterial growth following brief exposure to an antibiotic. In this study, the in vitro PAE of PDT using erythrosine and light emitting diode on S. mutans ATCC 25175 was investigated. The PAE of PDT for 1 s irradiation and 3 s irradiation were 1.65 h and 2.1 h, respectively. The present study thus confirmed PAE of PDT using erythrosine on S. mutans.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2036-2042
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• 2016

We evaluated the potentials of 10 isothiocyanates (ITCs) from cruciferous vegetables and radish root hydrolysate for inhibiting the growth of oral pathogens, with an emphasis on assessing any structure-function relationship. Structural differences in ITCs impacted their antimicrobial activities against oral pathogens differently. The indolyl ITC (indol-3-carbinol) was the most potent inhibitor of the growth of oral pathogens, followed by aromatic ITCs (benzyl ITC (BITC) and phenylethyl ITC (PEITC)) and aliphatic ITCs (erucin, iberin, and sulforaphene). Sulforaphene, which is similar in structure, but has one double bond, showed higher antimicrobial activity than sulforaphane. Erucin, which has a thiol group, showed higher antimicrobial activity than sulforaphane, which has a sulfinyl group. BITC and iberin with a short chain exhibited higher antimicrobial potential than PEITC and sulforaphane with a longer chain, respectively. ITCs have strong antimicrobial activities and may be useful in the prevention and management of dental caries.

• International Journal of Oral Biology
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• 제46권1호
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• pp.45-50
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• 2021

This study evaluated the antimicrobial activity of Endoseal TCS, an mineral trioxide aggregate-based root canal sealer, mixed with water-soluble mangostin derivatives (WsMD) of Garcinia mangostana L. (mangosteen) ethanol extract against Enterococcus faecalis and Staphylococcus aureus. The antibacterial activity of Endoseal TCS mixed with WsMD against three strains of E. faecalis and three strains of S. aureus was performed using agar diffusion test. The data showed that Endoseal TCS mixed with 0.115% WsMD had a zone of inhibition of 0.7 ± 0.2-2.4 ± 0.1 mm. The results suggest that Endoseal TCS mixed with WsMD of Garcinia mangostana L. ethanol extract is useful as a root canal sealer with antibacterial activity against E. faecalis and S. aureus.

• International Journal of Oral Biology
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• 제48권4호
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• pp.45-49
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• 2023

Digital dentistry has witnessed significant advancements in recent years, driven by extensive research following the introduction of cutting-edge technologies such as CAD/CAM and 3D oral scanners. Until now, 2D images obtained via x-ray or CT scans were critical to detect anomalies and for decision-making. This review describes the main principles and applications of supervised, unsupervised, and reinforcement learning in medical applications. In this context, we present a diverse range of artificial intelligence networks with potential applications in dentistry, accompanied by existing results in the field.

• Journal of Periodontal and Implant Science
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• 제48권5호
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• pp.284-294
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• 2018

Purpose: Epithelial barrier dysfunction is involved in the pathophysiology of periodontitis and oral lichen planus. Estrogens have been shown to enhance the physical barrier function of intestinal and esophageal epithelia, and we aimed to investigate the effect of estradiol (E2) on the regulation of physical barrier and tight junction (TJ) proteins in human oral epithelial cell monolayers. Methods: HOK-16B cell monolayers cultured on transwells were treated with E2, an estrogen receptor (ER) antagonist (ICI 182,780), tumor necrosis factor alpha ($TNF{\alpha}$), or dexamethasone (Dexa), and the transepithelial electrical resistance (TER) was then measured. Cell proliferation was measured by the cell counting kit (CCK)-8 assay. The levels of TJ proteins and nuclear translocation of nuclear factor $(NF)-{\kappa}B$ were examined by confocal microscopy. Results: E2 treatment increased the TER and the levels of junctional adhesion molecule (JAM)-A and zonula occludens (ZO)-1 in a dose-dependent manner, without affecting cell proliferation during barrier formation. Treatment of the tight-junctioned cell monolayers with $TNF{\alpha}$ induced decreases in the TER and the levels of ZO-1 and nuclear translocation of $NF-{\kappa}B$. These $TNF{\alpha}-induced$ changes were inhibited by E2, and this effect was completely reversed by co-treatment with ICI 182,780. Furthermore, E2 and Dexa presented an additive effect on the epithelial barrier function. Conclusions: E2 reinforces the physical barrier of oral epithelial cells through the nuclear ER-dependent upregulation of TJ proteins. The protective effect of E2 on the $TNF{\alpha}-induced$ impairment of the epithelial barrier and its additive effect with Dexa suggest its potential use to treat oral inflammatory diseases involving epithelial barrier dysfunction.

• International Journal of Oral Biology
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• 제38권4호
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• pp.149-154
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• 2013

In general, oleanolic acid (OA) and ursolic acid (UA) have antimicrobial effect against Gram-positive bacteria but not Gram-negative bacteria whereas sophoraflavanone G has antimicrobial activity against both bacterial types. However, the antimicrobial effects of OA, UA, and sophoraflavanone G against periodontopathogens have not been studied to any great extent. The aim of this study was to investigate antimicrobial effect of OA, UA, and sophoraflavanone G against 15 strains (5 species) of oral Gram-negative bacteria, which are the major causative bacteria of periodontal disease. The antimicrobial activity was evaluated by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations. OA and UA showed antimicrobial effects against all of the Porphyromonas gingivalis strains tested and also Prevotella intermedia ATCC $25611^T$. Interestingly, P. intermedia ATCC 49046 showed greater resistance to OA and UA than P. intermedia ATCC $25611^T$. In contrast, sophoraflavanone G had antimicrobial activity against all strains, with MIC and MBC values below $32{\mu}g/ml$, except Aggregatibacter actinomycetemcomitans. These results indicate that sophoraflavanone G may have potential for use in future oral hygiene products such as dentifrices and gargling solution to prevent periodontitis.

• International Journal of Oral Biology
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• 제35권3호
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• pp.107-111
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• 2010

Treponema denticola is a gram-negative anaerobe that can cause periodontal disease. The adhesion of this bacterium to host tissues is considered to be the primary event in the colonization and infection of a host. Fibrinogen is generally found in damaged tissues resulting from periodontitis. The binding ability of T. denticola to fibrinogen may therefore be an important virulence factor in inducing periodontal diseases. It has been reported recently that oral spirochetes can be labeled with fluorescent fatty acids and we speculated that this labeling method could be used in an oral spirochete binding assay. The binding of several different strains of T. denticola to immobilized human fibrinogen was therefore tested using the fluorescent fatty acid labeling method. In the case of immobilized fibrinogen, the T. denticola ATCC 35405 strain showed saturable binding to immobilized fibrinogen. Indeed, all four different T. denticola strains tested in this experiment, T. denticola ATCC 35405, T. denticola ATCC 33520, T. denticola ATCC 35404 and T. denticola OTK showed binding to fibrinogen. The fluorescent fatty acid labeling method thus shows utility in binding assays for T. denticola, different strains of which can generally bind to immobilized fibrinogen.

• International Journal of Oral Biology
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• 제42권3호
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• pp.143-147
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• 2017

In a previous study, Peptoniphilus mikwangii was isolated from the human oral cavity as a new species. The purpose of this study was to develop P. mikwangii-specific PCR primers. The PCR primers were designed, based on the nucleotide sequence of 16S ribosomal RNA (16S rDNA). The specificity of the primers was tested using genomic DNAs of 3 strains of P. mikwangii and 27 strains (27 species) of non-P. mikwangii bacteria. The sensitivity of primers sensitivity was determined using PCR, with serial dilutions of the purified genomic DNAs (4 ng to 4 fg) of P. mikwangii KCOM $1628^T$. The data showed that P. mikwangii-specific qPCR primers (B134-F11/B134-R1 & B134-F5/B134-R5) could detect only P. mikwangii strains, and 400 fg or 40 fg of P. mikwangii genome DNA. These results suggest that PCR primers are useful in detecting P. mikwangii from the oral cavity.