• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.312-319
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• 2005

Streptococcus mutans and Streptococcus sobrinus are major etiological agents in enamel demineralization around orthodontic appliances. This study was designed to examine the prevalence of these streptococci on orthodontic brackets in vivo using polymerase chain reaction. Four incisor brackets in the upper and lower arches were removed and collected from 80 patients at the time of debonding. The genomic DMA of adhered bacteria was extracted and each dextranase gene of S. mutans and S. sobrinus was amplified using the specific oligonucleotide primers. The results showed that the maxillary incisor brackets were colonized by both cariogenic streptococci to a somewhat higher degree than that taken from the mandible. The prevalence of S. mutans was $50.0\%$ on the maxillary incisor brackets and $33.8\%$ on the mandibular incisor brackets, and that of S. sobrinus was $17.5\%$ and $15.0\%$, respectively. Both species were detected on the maxillary incisor brackets of 7 patients $(8.8\%)$ and the mandibular incisor brackets of 5 patients $(6.3\%)$. These results suggest that cariogenic streptococci can adhere to the incisor brackets and may be resident species on the incisor brackets.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.406-415
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• 2020

Silver diamine fluoride (SDF) is an effective and efficient agent for arresting dental caries. It can be useful in treating children with behavioral or medical limitations. The purpose of this study was to evaluate the antimicrobial effect of SDF by using salivary biofilm. Pellicle-like saliva coated structure was prepared by using unstimulated saliva. For developing cariogenic biofilm, Streptococcus mutans was added to the mixture of pooled saliva and inoculated into a saliva coated glass or chamber. SDF was applied to cariogenic biofilm to evaluate the antimicrobial effect of SDF. As time passed, total bacteria and S. mutans were reduced after application of SDF (p < 0.000). Confocal laser scanning microscope also showed the increment of the ratio of dead cell. As a result of experiment using enamel and dentin of primary teeth, it was confirmed that the growth of cariogenic biofilm was inhibited when the SDF was treated (p = 0.029 each). This study showed excellent anti-microbial effect of SDF. And anti-caries effect in clinical practice can be expected.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.140-148
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• 2022

This study aimed to evaluate the effect of silver diamine fluoride (SDF) and potassium iodide (KI) on the formation of cariogenic biofilm and surface roughness in vitro. A total of 48 bovine dentin specimens with artificially induced caries were prepared and divided into 3 groups of 16: untreated control, SDF-treated, and SDF-treated followed by KI (SDFKI). Ten specimens from each group were used to observe microbial adhesion. Multispecies cariogenic biofilms including Streptococcus mutans, Lactobacillus casei, and Candida albicans were cultured on the specimens. Microbes were cultured for 24 hours, and the colony-forming unit was calculated. The remaining specimens were observed by atomic force microscope and scanning electron microscope (SEM). The number of bacteria was significantly lower in the SDF and SDFKI groups. KI did not inhibit the antibacterial activity of SDF significantly. SEM images showed particles generated after SDF and SDFKI application were deposited on the dentin, but there was no significant difference in surface roughness between the 3 groups. This study confirmed that SDF and SDFKI application did not have a significant effect on the surface roughness of dentin, but effectively inhibited the formation of the early cariogenic bacterial film after 24 hours compared to the control.

• International Journal of Oral Biology
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• v.43 no.3
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• pp.123-127
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• 2018

Polyphenon 60 refers to the mixture of catechins present in green tea. The aim of this study was to investigate the antimicrobial activities of polyphenon 60 against 4 strains of Streptococcus mutans and 2 strains of Streptococcus sorbrinus, which are the major causative bacteria of dental caries. The minimum bactericidal concentration (MBC) values of polyphenon 60 for S. mutans and S. sobrinus were determined and the effect of biofilm formation inhibition of that was evaluated. The MBC value of polyphenon 60 against the bacterial strains was 2.5 mg/ml except for one particular strain, S. mutans KCOM 1128 for which the value was 1.25 mg/ml. The results of biofilm formation inhibition assay revealed that polyphenon 60 inhibited biofilm formation more than 90% at a concentration of 2.5 mg/ml. It was apparent that polyphenon exhibited biofilm formation inhibition activity along with bactericidal effect against S. mutans and S. sobrinus. Therefore, it is proposed that polyphenon 60 as one of the components of bactericidal agents could be useful in developing oral hygiene products, toothpaste or gargling solution.

• International Journal of Oral Biology
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• v.40 no.2
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• pp.79-83
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• 2015

The purpose of the study was to investigate the antimicrobial activity of the methanol extract of Coptidis rhizome against the type strains of cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, and the periodontopathogens, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extract and the methanol extract fractions of Coptidis rhizome separated by silica gel chromatography were evaluated by determining the minimal bactericidal concentration (MBC) values, using the microdilution method. The cell viability test of the extracts of Coptidis rhizome on the KB cells was also studied by methyl thiazolyl tetrazolium (MTT) assay. Our results showed that the 11th fraction (F11) of the methanol extract had the greatest antimicrobial activity against the tested bacteria, with no associated cytotoxicity on the KB cells, upto a concentration of $50{\mu}g/ml$. These results suggest that the silica gel chromatography fraction F11 of the methanol extract of Coptidis rhizome, could be useful in the development of oral hygiene products as an antimicrobial agent for the prevention of dental caries and periodontal diseases.

• International Journal of Oral Biology
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• v.39 no.4
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• pp.169-176
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• 2014

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format $O_{(1-6)}XXXXX-NH_2$, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-$NH_2$ (pep-1) and WXXXXN-$NH_2$ (pep-2), and one positioned peptide, RRRWRN-$NH_2$ (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic ${\alpha}$-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

• Journal of dental hygiene science
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• v.19 no.4
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• pp.288-293
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• 2019

Background: Dental caries is one of several prevalent oral diseases caused by dental plaque biofilms. This study evaluated the anti-cariogenic effects of a bamboo salt (BS) and sodium fluoride (NaF) mixture on oral bacteria. Methods: The effects of several mixtures of NaF and BS on acid production, growth, and adhesion to glass beads of Streptococcus mutans, and their anti-cariogenic properties were investigated. The growth of S. mutans was measured according to optical density at 3, 6, 9, 12, 15, 18, and 24 hours after treatment using spectrophotometry at a wavelength of 600 nm, while pH was measured using a pH meter. Adhesion of S. mutans was measured according to the weight of glass beads from each group before and after incubation. Gene expression was measured using real-time polymerase chain reaction. Acid production and growth patterns of S. mutans were compared using repeated measures analysis of variance, followed by Scheffe's post-hoc test. The Kruskal-Wallis test was used to compare adhesion, followed by the Mann-Whitney test. Gene expression in the experimental and control samples was compared using the Student's t-test. Results: Growth, acid production, and adhesion of S. mutans were inhibited in all experimental groups. Expression of gft and fructosyltransferase in S. mutans was inhibited in all groups. A mixture of NaF and BS significantly reduced growth, acid production, adhesion, and gene expression of S. mutans compared with the other groups. Conclusion: Results of the present study demonstrated that a mixture of NaF and BS was useful as a mouth rinse in preventing dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.618-624
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• 2002

Effect of the roasted barley tea in commercial markets on the adherence to the saliva-coated hydroxyapatite(HA) beads and the cell surface hydrophobicity of Streptococcus mutans and Streptococcus sobrinus as cariogenic microorganism was examined in vitro. Adherence activity and hydrophobicity in bacteria tested in all the barley tea samples decreased and the values were different according to the type of tea and the type of treatment. The inhibition of bacterial adsorption to HA beads suggest that barley tea active molecules as catechins and melanoidins may adsorb to a host surface, preventing the tooth receptor from interacting with any bacterial adhesions. The obtained results showed that the barley tea may inhibit bacterial adherence, the first step of the pathogenesis of dental caries in which these microorganism are involved.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.132-139
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• 2024

This study aimed to compare the fluoride-releasing ability and degree of microbial attachment of a newly developed glass-hybrid restorative material (GH) with those of a high-viscosity glass ionomer (HvGIC), resin-modified glass ionomer (RMGI), and composite resin (CR). In addition, the correlation between fluoride-releasing ability and microbial attachment between materials was evaluated. Specimens were prepared in a disc shape and divided into 4 groups according to the materials (GH, HvGIC, RMGI, and CR). The fluoride release experiments were performed in each group (n = 15). The amount of fluoride released was measured on days 1, 3, 7, 14, 28, and 42 after storage. For the microbial attachment experiment, 12 specimens were produced per group using Mutans Streptococci (S.mutans ), a cariogenic microorganism. S. mutans was cultured on the specimens for 24 hours, and the number of bacteria was measured. GH had the highest cumulative fluoride release and showed a significant difference when compared with RMGI (p = 0.001) and CR (p < 0.0001). Microbial attachment was the lowest in GH; however, no significant difference was observed between the materials (p = 0.169). There was no significant correlation between fluoride release from materials and microbial attachment (p > 0.05). From this perspective, remineralization of low-mineralized areas could be expected due to the high fluoride release of GH, and the effect of delaying the progression of dental caries could be predicted from the low cariogenic microbial attachment. Therefore, GH might be a useful restorative material for treating immature permanent teeth with hypomineralized enamel. However, further studies are needed about the degree of remineralization of hypomineralized areas after restoration and the capacity to recharge fluoride.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.133-138
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• 1999

To study the antimicrobial effect of fluoride-releasing removable orthodontic appliances, 0 wt%(Group 1), 5 wt%(Group 2) and 10 wt%(Group 3) of $CaF_2$ were added to orthodontic resin. The specimens were then put in media in which S. mutans and Lactobacillus, known cariogenic bacteria, were cultured. Inhibiting zones were measured 24, 48 and 72 hours later. The following conclusions were reached: 1 In the Lactobacillus media, no zone of inhibition was observed regardless of the time passed. 2. In the S. mutans media, zones of inhibition were observed after 48 hours. 3. S. mutans showed greater inhibition in Group 3 compared to Group 2, after 72 hours rather than 48 hours(p<0.01).