• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.397-405
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• 2020

The aim of this study is to compare cariogenic characteristics of fluoride-sensitive Streptococcus mutans [fluoride-sensitive (FS) S. mutans ] and fluoride-resistant Streptococcus mutans [fluoride-resistant (FR) S. mutans] in the presence of sucrose, and to evaluate its effect on cariogenic biofilm formation. S. mutans ATCC 25175 was continuously cultured in trypticase soy broth (TSB) containing NaF (70 ppm) for 40 days to generate FR S. mutans. FS and FR S. mutans were inoculated in TSB with or without 2% sucrose, and optical density and pH were measured every hour. An oral biofilm was formed using saliva bacteria and analyzed through confocal laser scanning microscopy and CFU count. Finally, the expression of glucosyltransferases genes of both S. mutans was investigated through RT-PCR. FR S. mutans exhibited slower growth and lower acidogenicity in the presence of sucrose compared to FS S. mutans . Both cariogenic and single species biofilm formation was lower in the presence of FR S. mutans, along with reduced number of bacteria. FR S. mutans showed significantly low levels of gtfB, gtfC, and gtfD expression compared to FS S. mutans . On the basis of results, FR S. mutans may be less virulent in the induction of dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.459-465
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• 1999

The inhibition degree of the isolated bacteria on plaque formation of Streptococcus mutans, and the effect of these bacterial genus on the concentration of total bacteria in saliva were assessed with the following. The effectiveness of the isolated bacteria on the inhibition of plaque formation was assessed culturing Streptococcus mutans in the beaker with orthodontic wires. The mean weight of plaque produced on a wire was 152mg in the culture of Streptococcus mutans only, whereas being reduced to 4mg, 78mg, or 72mg in the combined culture of Streptococcus mutans and Enterococcus durans, Lactobacillus acidophilus, or Streptococcus oralis. The colony forming units (CFU) of Streptococcus mutans were $3.6{\times}10^8$ per ml in the culture of Streptococcus mutans, only, wheras being $1.4{\times}10^6,\;5.6{\times}10^6,\;or\;3.8{\times}10^6$ per ml in the combined culture of Streptococcus mutans and Enterococcus durans, Lactobacillus acidophilus, or Streptococcus oralis. When saliva from children was inoculated on brain heart infusion agar, the colony forming units of bacteria were $4.8{\times}10^6\;to\;1.3{\times}10^9$ per ml of saliva. The concentration of Enterococcus, Lactobacillus, or Streptococcus inhibiting Streptococcus mutans in saliva was not proportioned to that of total bacteria replicated on brain heart infusion agar. These results indicate that the isolated bacteria inhibited the replication of Streptococcus mutans, resulting into inhibiting the formation of plaque, but the concentration of Enterococcus, Lactobacillus, or Streptococcus inhibiting Streptococcus mutans, in saliva might not affect the total bacterial concentration of saliva.

• Journal of Korean society of Dental Hygiene
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• v.12 no.6
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• pp.1158-1164
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• 2012

Objectives : The aim of the present study was to measure the level of Streptococcus mutans(S. mutans), the major causative agent in dental caries, and to examine the relationship between S. mutans level and dental caries experience. Methods : The present study was carried out in 41 university students. S.mutans plaque was detected in the saliva using Dentocult$^{(R)}$-SM and was measured in absorbance. The data were analyzed in the relevance for number of dental caries experience. Results : The group of S. mutans value has progressive caries, which was higher than that of non-suffering caries(p<0.05). More caries experience showed higher value of S. mutans(p>0.05). According to the relationship with DMFT, level of S. mutans and absorbance, correlation with the level of salivary S. mutans is shown statistically highly significant (p<0.01). The level of S. mutans in saliva and plaque and absorbance is statistically significant(p<0.05). Conclusions : The levels of S. mutans in both group of high caries experience and progressive caries was highly detected, continuous oral health management should be carried out to prevent the possible dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.10-21
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• 2015

The purpose of this study was to determine the usefulness of a detection method for Streptococcus mutans in saliva with monoclonal antibodies developed targeting Ag I/II and glucosyltransferases (gtf B, gtf C and gtf D) in Streptococcus mutans. In the three groups tested (adults, minors, and minors under orthodontic treatment), the results of the DMFT scores, the colony density (CFU/mL) in their saliva was measured using $Dentocult^{(R)}$-SM strip mutans, polymerase chain reaction was performed to test whether Streptococcus mutans and Streptococcus sobrinus were present, and Streptococcus mutans detecting tests performed in their saliva using four types of monoclonal antibody were collected. In conclusion, it was demonstrated that the Streptococcus mutants plays more important role in forming dental caries compared to Streptococcus sobrinus, and that the monoclonal antibodies against glucosyltransferases (gtf B, gtf C, gtf D) and Ag I/II of Streptococcus mutans are superior in detecting Streptococcus mutans to $Dentocult^{(R)}$-SM strip mutans or polymerase chain reaction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.384-389
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• 2012

As part of our screening of anticariogenic agents from medicinal plants, the ethanol extracts of 25 herbs widely used in the fork medicine were tested for the antimicrobial activity against a cariogenic bacterium Streptococcus mutans ATCC 25175. The ethanol extracts of Coptis chinensis, Sophora flavescens, Glycyrrhiza uralensis, Mentha arvensis, and Saururus chinensis showed antimicrobial activities against S. mutans. The extracts of Coptis chinensis and Sophora flavescens among these medicinal plants showed significant antomicrobial activity against S. mutans. These results suggested that the extracts of Coptis chinensis and Sophora flavescens could be the potential source of antimicrobial agent against S. mutans ATCC 25175.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.561-567
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• 2002

Xylitol is a 5-carbons carbohydrate, which can be replaced with sucrose for preventing caries. The replication of Streptococcus mutans and its formation of artificial plaque were studied in the media containing xylitol. The combined effect of xylitol and other carbohydrates on Streptococcus mutans was also studied. The replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol. Streptococcus mutans replicated at the initial stage of incubation in the media containing glucose, fructose or lactose, while replicating from the beginning of incubation in the media containing fructose as combining with xylitol. The formation of artificial plaque by Streptococcus mutans was significantly reduced in the media containing with xylitol and fructose. These results indicated that the replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol, and the formation of artificial plaque by Streptococcus mutans was significantly inhibited in the media containing xylitol and fructose.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.5
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• pp.854-858
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• 2010

Streptococcus mutans (S. mutans) plays an important role in the information of dental plaque and it is being noticed as major causative bacteria of dental caries. In the present study, inhibitory effects of the ethanol extract of Dianthus superbus Linne (D. superbus) on the growth, acid production, adhesion and water-insoluble glucan synthesis of S. mutans were examined. The ethanol extract of D. superbus (0.5 - 4 mg/ml) significantly lowered the growth of S. mutans in a dose dependent manner. The acid production of S. mutans were inhibited by the presence of ethanol extract of D. superbus(1 - 4 mg/ml) significantly. The ethanol extract of D. superbus (0.25 - 4 mg/ml) also significantly lowered the adherence of S. mutans in a dose dependent manner. In water-insoluble glucan synthesis assay, 0.25 - 4 mg/ml of the ethanol extract of D. superbus significantly inhibited the formation of water-insoluble glucan. These results suggest that D. superbus may inhibit the caries-inducing properties of S. mutans. Further studies are necessary to clarify the active constituents of D. superbus responsible for such biomolecular activities.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.462-469
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• 2004

The aim of this study was to investigate the susceptibility of mutans streptococci (S. mutans and S. sobrinus) and Streptococcus anginosus, for seven antibiotics, penicillin G, amoxicillin, ciprofloxacin, cefuroxime, erythromycin, bacitracin, and vancomycin. The minimum inhibitory concentration (MIC) of seven antibiotics against 3 species (type strains) of mutans streptococci and S. anginosus, 10 strains (wild type) of S. mutans, 7 strains (wild type) of S. sobrinus, and 11 strains (wild type) of S. anginosus, were measured by broth dilution method. All of the type strains of mutans streptococci and S. anginosus had the same susceptibility for penicillin G, amoxicillin, cefuroxime and bacitracin. Type strain of S. anginosus was sensitive in ciprofloxacin, but those of mutans streptococci were not. All of the clinical isolates of mutans streptococci and S. anginosus had the same susceptibility for the seven antibiotics. Our data reveal that mutans streptococci and S. anginosus have similar antibiotic-resistant character. In addition. these results may offer the basic data to verify the antibiotic-resistant mechanism of mutans streptococci and S. anginosus.

• YAKHAK HOEJI
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• v.49 no.2
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• pp.122-127
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• 2005

Dental caries is one of the most common oral diseases in the world. Glucosyltransferase (Gtase) of Streptococcus mutans (S. mutans) plays an important role in the develo pment of dental caries. For the purpose to develop anti- caries, we examined the effect of metabolites isolated from Streptomyces sp. M-20 on Gtase and the growth of S. mutans. Streptomyces sp. M-20 isolated from Mongolian soil showed 95~96% sequence homology with that of Streptomyces lin- colnensis. The metabolites of Streptomyces sp. M-20 were partially purified by extraction with ethyl acetate, silica gel column chromatography and preparative TLC. Partially purified metabolite, red colored component (MR-20) in ethyl acetate fraction showed potent antibacterial activitiy against S. mutans and inhibitory activity against Gtase purified from S. mutans, while another isolated yellow component (MY-20) showed no activity against S. mutans. The inhibitory activity of MR-20 against Gtase was confirmed by activity staining on SDS-polyacrylamide gel electrophoresis. The concentration of MR-20 for 50% inhibition $(IC_{50})$ against Gtase activity was $60{\mu}g/ml$. These results suggest that MR-20 can be developed for antibacterial agent and anticaries.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.217-221
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• 2015

Cariogenic Streptococcus mutans encounters a variety of host defense factors produced in oral cavity. Nitric oxide (NO) and NO-mediated reactive nitrogen species are potential antimicrobials of innate immunity that can threaten the fitness of S. mutans in their ecological niches. Streptococcal strategies to detoxify cytotoxic NO, which allow S. mutans to persist in caries or other environments of the oral cavity, remain unknown. In this study, we directly measured NO consumption rates of S. mutans isolated in Korea. Surprisingly, all S. mutans strains were unable to consume exogenous NO efficiently, while an intracellular parasite Salmonella enterica serovar Typhimurium expressing the NO-metabolizing enzyme flavohemoglobin consumed most of the NO. This result suggested that S. mutans has alternative detoxification systems for tolerating NO-induced nitrosative stresses.