• International Journal of Oral Biology
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• v.39 no.2
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• pp.81-86
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• 2014

Xylitol is a five-carbon sugar alcohol that inhibits the growth of oral streptococci, including Streptococcus mutans. In this study, we tested xylitol sensitivity among the oral streptococci. We also compared nucleotide homology of putative fructose phosphotransferase system (PTS) and xylitol sensitivity, since xylitol is transported via the fructose PTS. Among the tested Streptococci, S. pneumonia showed the highest resistance to xylitol while S. gordonii and S. sanguinis showed the most sensitive growth inhibition. These streptococci could be grouped according to their xylitol sensitivity. S. mutans and S. salivarius showed similar bacterial growth inhibition by xylitol. S. mitis, S. oralis, S. pneumonia, S. intermedius and S. anginosus showed relatively low sensitivity to xylitol. When the genetic homologies of five fructose PTSs were compared among the tested streptococci, closely related streptococci showed similar sensitivity to xylitol. Taken together, fructose PTSs may mediate the sensitivity to xylitol in oral streptococci.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.19-43
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• 1997

The barrier membranes for GTR procedure could be affected bY bacterial contamination after exposure to oral environment. This study was done to evaluate whether the tetracycline impregnated barrier membranes could inhibit bacterial attachment and penetration into membranes. The resorbable membrane(polylactic and polyglycolide copolymer, $Resolute^{(R)}$, W.L Gore and Associates, Inc..USA) and the non-resorbable membrane(e-PTFE; Gore-TexTM, W.L. Gore & Associates, Inc.,USA) were cut into 4mm discs and trated with 5% tridodecylmethylammonium chloride solution in ethanol and dried in air. The membranes were immersed in tetracycline(TC) solution (100mg/ml, pH 8.0) and dried. To the maxillary canine-premolar region in six periodontally healthy volunteers, removable acrylic devices were inserted, on which 8 cylindrical chambers were glued with TC impregnated and non-impregnated discs, the membrane discs were examined for bacterial attachment and penetration, and structural changes under SEM and LM. From the 1st day to the 7th day, membranes showed bacterial plaque formation composed of cocci and rods. Thereafter, filamentous bacteria appeared and the plaque thickness increased. The TC impregnated e-PTFE membranes showed less bacterial attachment and delayed in bacterial plaque maturation than non-treated membranes. As for bacterial penetration, the TC impregnated e-PTFE membranes showed superficial invasion and infrequent presence of bacteria in unexposed inner surface at the 4th week. while the non-treated e-PTFE membranes showed deep bacterial invasion at the 2nd week and frequent presence of internal bacteria at the 4th week. The resorbable membranes started to be resorbed at the 2nd week and were perforated at the 4th week, regardless of TC treatment. In conclusion, bacterial plaque formation and penetration was efficiently delayed in TC impregnated e-PTFE membranes, whereas resorbable membranes were similar in bacterial invasion due to membrane degradation and perforation, regardless of TC treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.1
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• pp.51-57
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• 2015

The etiology of periodontal disease is multifactorial. Exogenous stimuli such as bacterial pathogens can interact with toll-like receptors to activate intracellular calcium signaling in gingival epithelium and other tissues. The triggering of calcium signaling induces the secretion of pro-inflammatory cytokines such as interleukin-8 as part of the inflammatory response; however, the exact mechanism of calcium signaling induced by bacterial toxins when gingival epithelial cells are exposed to pathogens is unclear. Here, we investigate calcium signaling induced by bacteria and expression of inflammatory cytokines in human gingival epithelial cells. We found that peptidoglycan, a constituent of grampositive bacteria and an agonist of toll-like receptor 2, increases intracellular calcium in a concentration-dependent manner. Peptidoglycan-induced calcium signaling was abolished by treatment with blockers of phospholipase C (U73122), inositol 1,4,5-trisphosphate receptors, indicating the release of calcium from intracellular calcium stores. Peptidoglycan-mediated interleukin-8 expression was blocked by U73122 and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester). Moreover, interleukin-8 expression was induced by thapsigargin, a selective inhibitor of the sarco/endoplasmic reticulum calcium ATPase, when thapsigargin was treated alone or co-treated with peptidoglycan. These results suggest that the gram-positive bacterial toxin peptidoglycan induces calcium signaling via the phospholipase C/inositol 1,4,5-trisphosphate pathway, and that increased interleukin-8 expression is mediated by intracellular calcium levels in human gingival epithelial cells.

• International Journal of Oral Biology
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• v.39 no.1
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• pp.9-13
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• 2014

Streptococci are among the normal human microflora that populate the oral cavity. However, oral streptococci are known as a major causative agent for dental caries and bacterial endocarditis. Tetracycline is a broad-spectrum antibiotic that is used for oral infections but two mechanisms of tetracycline resistance in streptococci have been reported. The tet(K) and tet(L) genes in these bacteria are related to the active efflux of tetracycline, whereas tet(M) and tet(O) confer ribosomal protection from this antibiotic. It has been reported that the tetracycline resistance of streptococci is related mainly to the activity of tet(M) and tet(O). In our present study, we examined the prevalence of tet(M) and tet(O) in oral streptococci isolated from Korean dental plaques using PCR. One hundred and forty eight of 635 isolates (23.3%) were tetracycline resistant; 68 of these strains (46%) harbored tet(M) and 3 strains (2%) were positive for tet(O). However, tet(M) and tet(O) did not co-exist in any of the resistant strains. Seventy seven of the 148 tetracycline resistant strains (52%) were negative for both the tet(M) and tet(O) genes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.4
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• pp.480-484
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• 2008

The incidence of aspergillosis infections in the maxillary sinus has increased recently, because of overuse of antibiotics, steroids, anticancer agents, immunosuppressant, antimetabollites, and uncontrolled diabetes mellitus. The clinical features of maxillary sinus aspergillosis include pain, swelling and foul odor nasal excretion. This needs to be differentiated from bacterial maxillary sinusitis, and surgical treatment with antifungal agents are suggested. Recently, we treated two patients with maxillary sinus aspergillosis surgically (Caldwell Luc operation) and with antifungal agents(itraconazole). The results were satisfactory so we report these cases with literature review.

• Journal of Oral Medicine and Pain
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• v.44 no.3
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• pp.140-144
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• 2019

Actinomycosis is rare, chronic, slowly progressive disease caused by gram-positive anaerobic organisms from the Actinomycosis family that normally colonizes the oral cavity. Actinomycotic osteomyelitis is even more rare and refractory disease because diagnosis by bacterial culture is not easy. In our case, 80-year-old man visited our clinic with a complaint of swelling and severe sinus tracts without teeth evolvement on anterior mandible. Computed tomography (CT) scan demonstrated erosive bone destruction on anterior mandible, clinically suspected actinomycotic osteomyelitis. The patient also had thoracic actinomycosis on Lt. lower lung. We could diagnosis actinomycosis by histopathologic examination. He treated by conservative surgery and long term antibiotics. After 2 year, no recurrence was seen in CT scan.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.567-575
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• 2016

Objectives: The purpose of the study was to investigate dental care effects of periodontal diseases patients with systemic diseases. Methods: The study subjects were ten patients. The study consisted of direct examination and interview survey. Direct examination comprised pocket depth, bleeding on the brush, O'Leary plaque record, salivary flow rate, and oral bacterial culture for three months. Results: The number of diabetic patients was eight. Four patients xerostomia and one of them had 0.7 mL per minute of salivary flow rate, decreased O'Leary plaque record, and bleeding in the brush. Those who received education were able to take control of plaque management. They recognized the need for oral care and had good self-management of oral care skills. Conclusions: The professional dental care and oral health education improved periodontal health and self-management skills of plaque in periodontal disease patients with systemic diseases.

• International Journal of Oral Biology
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• v.36 no.1
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• pp.1-6
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• 2011

The purpose of this study was to develop species-specific real-time quantitative PCR (RT-qPCR) primers for use in the detection of Aggregatibacter actinomycetemcomitans. These primers were designed based on the nucleotide sequences of the RNA polymerase ${\beta}$-subunit gene (rpoB). We assessed the specificity of the primers against nine strains of A. actinomycetemcomitans, eight strains (three species) of the Haemophilus genus, and 40 strains of 40 other oral bacterial species. Primer sensitivity was determined by testing serial dilutions of the purified genomic DNAs of A. actinomycetemcomitans ATCC $33384^T$. Our data reveal that we had obtained species-specific amplicons for all of the tested A. actinomycetemcomitans strains, and that none of these amplicons occurred in any of the other species. Our PCR protocol proved able to detect as little as 2 fg of A. actinomycetemcomitans chromosomal DNA. Our findings suggest that these qRT-PCR primers are suitable for application in epidemiological studies.

• International Journal of Oral Biology
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• v.41 no.1
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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 the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.188-195
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• 2020

This study is aimed to evaluate and compare the surface roughness and microbial adhesion to alkasite restorative material (Cention N), resin-modified glass ionomer (RMGI), and composite resin. And to examine the correlation between bacterial adhesion and surface roughness by different finishing systems. Specimens were fabricated in disk shapes and divided into four groups by finishing methods (control, carbide bur, fine grit diamond bur, and white stone bur). Surface roughness was tested by atomic force microscope and surface observation was performed by scanning electron microscope. Colony forming units were measured after incubating Streptococcus mutans biofilm on specimens using CDC biofilm reactor. Cention N surface roughness was less than 0.2 ㎛ after finishing procedure. Control specimens of resin and Cention N specimens were significantly (p = 0.01) rougher. Pearson correlation coefficient (PCC = 0.13) indicated a weak correlation between surface roughness and S. mutans adhesion to the specimens. Compared with resin specimens, RMGI and Cention N showed lower microbial adhesion. Surface roughness and bacterial adhesion were not significantly different, regardless of the finishing systems.