• Journal of dental hygiene science
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• v.19 no.2
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• pp.86-95
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• 2019

The modern era of microbial genome analysis began in earnest in the 2000s with the generalization of metagenomics and gene sequencing techniques. Studying complex microbial community such as oral cavity and colon by a pure culture is considerably ineffective in terms of cost and time. Therefore, various techniques for genomic analysis have been developed to overcome the limitation of the culture method and to explore microbial communities existing in the natural environment at the gene level. Among these, DNA fingerprinting analysis and microarray chip have been used extensively; however, the most recent method of analysis is metagenomics. The study summarily examined the overview of metagenomics analysis techniques, as well as domestic and foreign studies on disease genomics and cluster analysis related to oral metagenome. The composition of oral bacteria also varies across different individuals, and it would become possible to analyze what change occurs in the human body depending on the activity of bacteria living in the oral cavity and what causality it has with diseases. Identification, isolation, metabolism, and presence of functional genes of microorganisms are being identified for correlation analysis based on oral microbial genome sequencing. For precise diagnosis and treatment of diseases based on microbiome, greater effort is needed for finding not only the causative microorganisms, but also indicators at gene level. Up to now, oral microbial studies have mostly involved metagenomics, but if metatranscriptomic, metaproteomic, and metabolomic approaches can be taken together for assessment of microbial genes and proteins that are expressed under specific conditions, then doing so can be more helpful for gaining comprehensive understanding.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.26-33
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• 2012

The purpose of this study was to find out the effect of dentifrice containing Horseradish (Armoracia rustica) root extracts on improvement of oral hygiene. The clinical evaluation was done participated by 80 adults volunteers who provided a informed consent for their participation. The participants were divided into two groups ; control group (using toothpaste without Horseradish extracts) and experimental group (using toothpaste containing Horseradish extracts). The checklist of the experiment includes the plaque index, gingival index and anti-caries activity. The anti-caries activity was measured by cultivating Streptococcus mutans for 48 hours then estimating the number of increased bacteria using Dentocult SM. The double-blind method was used in this study. The results of this study can be summarized as follows; 1. The plaque formation decreased 28% in control group, 58% in experimental group using dentifrice with Horseradish extracts compared to baseline data. 2. For gingival index, control group and experimental group showed 26% and 40% decrease compared to baseline data, respectively. 3. The score of caries activity test decreased by 4% for control group and 69% for experimental group compared to baseline data. According to the results, a dentifrice containing Horseradish extracts can improve oral hygiene.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.666-671
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• 2003

Dental caries are the most commonly occurring chronic diseases in the dental field. Because of increasing sugar consumption and extension of average human life, these diseases are widely found all over the world as the most typical cause for a person to lose a tooth. Therefore, the development of more effective, substantial and safe preventive agents against dental caries is strongly required. Streptococcus mutans is known as the causative bacterial playing the most important role informing plaque and it is being noticed as major causative bacteria of dental caries. The present study was designed to investigate the effect of Asarum sieboldii Miquel(Aristolochiaceae) extracts on the growth, acid production, adhesion, and insoluble glucan synthesis of Streptococcus mutans(S. mutans). Both methanol and aqueous extracts showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 100, 1,000 and 2,000 μg/ml compared to the control group(p<0.05 - p<0.01). The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 50% at the concentration of 10 μg/ml and complete inhibition was observed at the concentration of 2,000 μg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan from sucrose, methanol and aqueous extracts showed more than 70% inhibition over the concentration of 1,000 μg/ml. Hence, we conclude that Asarum sieboldii might be a candidate of anticaries agent.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.3
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• pp.161-165
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• 2015

Long QT syndrome (LQTs) is a rare congenital disorder of the heart's electrical activity. Patients with LQTs are at increased risk of developing fatal ventricular arrhythmias. Elevated levels of sympathetic stimulation can exacerbate this risk. Successful behavior management is indispensable in the treatment of patients with LQTs. However, many drugs involved in pharmacologic behavior management are known to adversely affect the QT interval. Therefore, careful selection of a sedative drug is essential in avoiding such incidences. A 10-year-old boy with a known diagnosis of LQTs required restorative treatment due to dental caries at the permanent molar. He required sedation since treatment was painful and dental phobia can trigger sympathetic stimulation, creating a dangerous situation for patients with LQTs. Therefore, the treatment was performed over two sessions under moderate sedation involving propofol combined with nitrous oxide. Restorative treatment was successful without any complications under sedation with a target-controlled infusion (TCI) of propofol. There was no significant QT prolongation during pulpal treatment. Propofol TCI may be a good candidate for sedation in patients with LQTs.

• International Journal of Oral Biology
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• v.39 no.1
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• pp.35-40
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• 2014

Halitosis is caused by consumption of certain foods or drinks and production of volatile sulfur compounds (VSCs) by periodontopathogens. VSCs-related halitosis is not easily removed using mechanical or chemical therapies such as dental floss, plaque control and mouth rinse. Lactobacillus are known to be probiotics and stimulate immune systems of human. Furthermore, L. casei ATCC 334 and L. rhamnosus GG have an effect on protection of dental caries in vitro studies. The aim of this study was to investigate effect of Lactobacillus on halitosis by Fusobacterium nucleatum- and Porphyromonas gingivalis-producing VSCs and to analyze inhibitory mechanism. The periodontopathogens were cultivated in the presence or the absence Lactobacillus, and the level of VSCs was measured by gas chromatograph. For analysis of inhibitory mechanisms, the susceptibility assay of the spent culture medium of Lactobacillus against F. nucleatum and P. gingivalis was investigated. Also, the spent culture medium of Lactobacillus and periodontopathogens were mixed, and the emission of VSCs from the spent culture medium was measured by gas chromatograph. L. casei and L. rhamnosus significantly reduced production of VSCs. L. casei and L. rhamnosus exhibited strong antibacterial activity against F. nucleatum and P. gingivalis. The spent culture medium of L. casei inhibited to emit gaseous hydrogen sulfide, methyl mercaptan and dimethyl sulfide from the spent culture medium of periodontopathogens. However, the spent medium of L. rhamnosus repressed only dimethyl sulfide. L. casei ATCC 334 may improve halitosis by growth inhibition of periodontopathogens and reduction of VSCs emission.

• 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 dental hygiene science
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• v.11 no.1
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• pp.37-40
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• 2011

Oleanolic acid (OA) and ursolic acid (UA) are triterpenoid compound present in many plants. This study examined the antimicrobial activity of OA and UA against Streptococcus downei. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC) and time kill curves. The MIC values of OA and UA for S. downei isolated from the Korean population were $8{\mu}g/ml$. OA and UA had a bactericidal effect on S. downei ATCC $33748^T$ above $2{\times}MIC$, $16{\mu}g/ml$ and $8{\mu}g/ml$, respectively. The results suggest that OA and UA can be used in the development of oral hygiene products for the prevention of dental caries.

• Journal of Korean society of Dental Hygiene
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• v.17 no.3
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• pp.527-537
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• 2017

Objectives: The purpose of this study was to examine the practice of oral hygiene behaviors and oral health status of long-term care facility residents and to analyze the factors related to salivary hemoglobin level which can predict active periodontal disease. Methods: From 30th October 2015 to 7th January 2016, a questionnaire was provided to 63 participants and their dental plaque and saliva samples were collected to assess the levels of salivary hemoglobin and dental plaque acidogenicity. In order to analyze the factors related to salivary hemoglobin level, multiple linear regression analysis was performed. Results: Toothbrushing was most frequently performed by the participants themselves (98.4%) and toothbrushing was performed after eating breakfast (81.3%). 68.8% of participants reported brushing their tongue. 35.9% of participants perceived having bad teeth, and 87.5% had high dental caries activity. The percentages of participants with hyposalivation and ${\geq}0.20{\mu}g/ml$ salivary hemoglobin level were 45.3% and 59.4%, respectively. The salivary hemoglobin level was significantly higher in the group in which stimulated salivary flow rate was ${\leq}0.70ml/min$, dental plaque acidogenicity was superior, and perceived having bad teeth (p<0.05). There was also a tendency for the salivary hemoglobin level to increase with age (p<0.05). Conclusions: Oral health status of the long-term care facility residents was still not improved, and the characteristics of salivary volume and dental plaque were important factors affecting salivary hemoglobin level. Therefore, it is necessary to operate an oral hygiene intervention program by oral health professionals in such facilities in order to provide residents with effective oral care aligned with their respective needs. Furthermore, it is necessary for caregivers to complete mandatory oral health education to improve the oral hygiene status of the long-term care facility residents.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.80-91
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• 2003

Mutans streptococci, especially S. mutans and S. sobrinus strongly implicated in pathogenesis of dental caries, the major cause of tooth loss in children. Use of an antibacterial agent controlling dental caries has been rationalized. The present study was performed to observe the antibacterial effect of inorganic polyphosphates (polyP) on S. mutans and S. sobrinus. S. mutans GS5 and S. sobrinus 6715 were grown in brain-heart infusion broth with or without polyP. Minimal inhibitory concentration (MIC) of polyP for S. mutans GS5 was determined to be 0.08% and that for S. sobrius 6715 was 0.17%. PolyP 15 added to the growing culture of S. mutans GS5 and S. sobrinus 6715 at their exponential phase was as effective in inhibiting the growth of S. mutans GS5 and S. sobrinus 6715 as polyP added at the very beginning of the culture. More than 85% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. mutans GS5 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. And more than 99.9% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. sobrinus 6715 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. Intracellular nucleotide release from S. mutans CS5 and S. sobrinus 6715 was increased in the presence of polyP 15 for 5h but was not really reversed by the addition of divalent cations like $Ca^{++}\;and\;Mg^{++}$. The majority of the cells appeared to be atypical in their shape, demonstrating accumulation of highly electron-dense granules and ghost cells. The overall results suggest that polyP have a strong bactericidal activity against S. mutans and S. sobrinus in which lysis in relation to chelation may not play the major role but unknown mechanism that possibly affects the viability of the bacterium may be involved. PolyP may be used as an agent for prevention of dental caries.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.27-32
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• 2015

Streptococcus mutans triggers dental caries establishment by two major factors. One is synthesis of organic acids which demineralize dental enamel and the other is synthesis of glucans which mediate the attachment of bacteria to the tooth surface. In the present study, we evaluated the effect of the ethanol extracts of Aconitum koreanum (A. koreanum ) on the growth and acid production of S. mutans. Ethanol extracts of the A. koreanum showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.016 mg/ml compared to the control groups (p<0.05). The extracts inhibited S. mutans adherence to hydroxyapatite treated with saliva, and cell adherence was repressed by 50%, 54% at the concentration of 0.063, 0.125 mg/ml. On the study of activation of glucosyltransferase which synthesizes water insoluble glucan form sucrose, the ethanol extract of A. koreanum showed remarkable inhibition over the concentration of 0.016, 0.031, 0.063 and 0.125 mg/ml (p<0.05). Especially on the concentration of 0.063, 0.125 mg/ml, the extracts suppressed the glucan synthesis by 100%. We analyzed the component of the extracts of A. koreanum. The results showed that the extract of A. koreanum had strong phenolic compound, glycosides and organic acids. These results suggest that A. koreanum may inhibit the caries-inducing properties of S. mutans, and which may be related with strong phenolic compound, glycosides and organic acids.