• Journal of dental hygiene science
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• v.24 no.1
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• pp.54-61
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• 2024

Background: The Korean name for Angelica gigas Nakai (AGN) is Cham-dang-gui, which grows naturally or is cultivated, and its dried roots are used in traditional herbal medicines. The AGN root exert various pharmacological effects. Despite the various pharmacological effects of the AGN root, there are no reports on its anti-oral microbial effects. The purpose of this study was to reveal the anti-oral microbial effect and the microbial and biochemical changes in oral microorganisms according to the concentration of the ethanol extract of AGN (EAGN) root, and to confirm the possibility of using EAGN as a plant-derived functional substance for controlling oral infectious microorganisms. Methods: Disk diffusion test, growth measurement, biofilm formation assay, and measurements of acid production and buffering capacity were performed to confirm the antibacterial effect of EAGN. Results: EAGN showed anti-oral bacterial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans at all concentrations, with S. mutans showing a more susceptible effect at concentrations above 5.0 mg/ml and A. actinomycetemcomitans at 3.75 mg/ml. EAGN treatment significantly reduced A. actinomycetemcomitans growth at all concentrations tested. Biofilm formation was significantly reduced at concentrations above 3.75 mg/ml for S. mutans and 2.5 mg/ml for A. actinomycetemcomitans. Acid production in S. mutans and A. actinomycetemcomitans was significantly increased by treatment with EAGN, and the buffering capacities of S. mutans and A. actinomycetemcomitans increased from an EAGN concentration of 3.75 mg/ml and above. Conclusion: EAGN showed anti-oral bacterial effects against both S. mutans and A. actinomycetemcomitans at concentrations above 3.75 mg/ml, which were thought to be related to the inhibition of their growth and biofilm formation. Therefore, EAGN can be used as a safe functional substance derived from medicinal plants owing to its antibacterial effects against S. mutans and A. actinomycetemcomitans.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.4
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• pp.437-445
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• 2017

The aim of this study was to investigate the effects of green tea, black tea, barley tea and roasted corn tea used in South Korea to make tea on the formation of Streptococcus mutans biofilm. The aqueous samples of 4 types of tea were extracted from commercial tea bags using cold water ($7^{\circ}C$) or hot water ($72^{\circ}C$). S. mutans UA 159 was introduced into 96-well plates which contained the tea samples and 1% sucrose media. Crystal violet staining was used to assess the effects of teas on S. mutans biofilm formation. In both groups of green tea and black tea, the biofilm significantly decreased with the solution of $50{\mu}L$ aqueous sample in $200{\mu}L$ media and $100{\mu}L$ aqueous sample in $100{\mu}L$ media (p < 0.05). S. mutans biofilm with $25{\mu}L$ of barley tea or roasted corn tea aqueous sample in hot water ($72^{\circ}C$) for 10 minutes showed significant decrease compared of green tea or black tea (p < 0.05). In this study, green tea and black tea suppress the formation of S. mutans biofilm.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.32-39
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• 2024

This study evaluated the additive impact of ethylenediamine tetraacetic acid (EDTA) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) biofilm by measuring colony-forming units and applying confocal laser scanning microscopy. Fifty-six bovine incisors, free from dental caries or structural defects, were utilized in this study. Dentin specimens were created by cutting with a low-speed diamond disk under a continuous flow of water, resulting in dimensions of 6.0 mm × 3.0 mm × 2.0 mm. The specimens were categorized into 4 groups: Control, EDTA, PDT, and EDTA + PDT. S. mutans ATCC 25175 was employed to establish biofilm on the dentin specimens. A 17% EDTA solution was applied for 1 min. For PDT, erythrosine served as the photosensitizer. Finally, a light-emitting diode source (385 - 515 nm) was employed in this study. The PDT group exhibited a significantly lower bacterial count than both the control and EDTA groups (p < 0.001). The EDTA + PDT group demonstrated a significantly reduced bacterial count compared to the other 3 groups (p < 0.001). This study demonstrated that EDTA enhances the antimicrobial efficacy of PDT on S. mutans biofilm. Even at a low concentration of photosensitizer, the combination of EDTA and PDT yields a significant antibacterial effect.

• Journal of Periodontal and Implant Science
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• v.47 no.4
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• pp.219-230
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• 2017

Purpose: The purpose of this study was to compare the characteristics of single- and dualspecies in vitro oral biofilms made by static and dynamic methods. Methods: Hydroxyapatite (HA) disks, 12.7 mm in diameter and 3 mm thick, were coated with processed saliva for 4 hours. The disks were divided into a static method group and a dynamic method group. The disks treated with a static method were cultured in 12-well plates, and the disks in the dynamic method group were cultured in a Center for Disease Control and Prevention (CDC) biofilm reactor for 72 hours. In the single- and dual-species biofilms, Fusobacterium nucleatum and Porphyromonas gingivalis were used, and the amount of adhering bacteria, proportions of species, and bacterial reduction of chlorhexidine were examined. Bacterial adhesion was examined with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results: Compared with the biofilms made using the static method, the biofilms made using the dynamic method had significantly lower amounts of adhering and looser bacterial accumulation in SEM and CLSM images. The proportion of P. gingivalis was higher in the dynamic method group than in the static method group; however, the difference was not statistically significant. Furthermore, the biofilm thickness and bacterial reduction by chlorhexidine showed no significant differences between the 2 methods. Conclusions: When used to reproduce periodontal biofilms composed of F. nucleatum and P. gingivalis, the dynamic method (CDC biofilm reactor) formed looser biofilms containing fewer bacteria than the well plate. However, this difference did not influence the thickness of the biofilms or the activity of chlorhexidine. Therefore, both methods are useful for mimicking periodontitis-associated oral biofilms.

• Journal of dental hygiene science
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• v.23 no.2
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• pp.103-111
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• 2023

Background: Some studies confirm the reduction of the number of Streptococcus mutans in saliva and dental plaque by Lactobacillus, however, these effects are not always confirmed in in vitro and clinical studies, and only the risk of dental caries has been reported. Our in vitro study aimed to reveal microbial and biochemical changes in the single cultures of S. mutans, Lactobacillus casei and Aggregatibactor actinomycetemcomitans and co-cultures of S. mutans and L. casei or A. actinomycetemcomitans according to sucrose concentration. We also aimed to confirm the anti-oral bacterial and anti-biofilm activities of L. casei and A. actinomycetemcomitans against S. mutans according to sucrose concentration. Methods: S. mutans (KCCM 40105), L. casei (KCCM 12452), and A. actinomycetemcomitans (KCTC 2581) diluted to 5×10⁶ CFU/ml were single cultured, and L. casei or A. actinomycetemcomitans applied at concentrations of 10%, 20%, 30% and 40% to S. mutans were co-cultured with selective medium containing 0%, 1% and 5% sucrose at 36.5℃ for 24 hours. Measurements of bacterial growth value and acid production, disk diffusion and biofilm formation assays were performed. Results: In the medium containing sucrose, the bacterial growth and biofilm formation by S. mutans, L. casei, and A. actinomycetemcomitans were increased. In contrast, 30% and 40% of L. casei in the medium containing 0% sucrose showed both anti-oral bacterial and anti-biofilm activities. This implies that L. casei can be used as probiotic therapy to reduce S. mutans in a 0% sucrose environment. Conclusion: The concentration of sucrose in the oral environment is important for the control of pathogenic bacteria that cause dental caries and periodontitis. To apply probiotic therapy using L. casei for S. mutans reduction, the concentration of sucrose must be considered.

• Korean Journal of Pharmacognosy
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• v.54 no.1
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• pp.27-37
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• 2023

This research was conducted to investigate the comprehensive effects of methanol extract of Coptidis rhizoma (MECR) against oral pathogen. We studied the antibacterial, anti-biofilm, anti-gingipain and anti-inflammatory activity of MECR. The minimum bactericidal concentration (MBC) of MECR was 100 ㎍/mL against several oral pathogens. The formation of biofilm of Streptococcus mutans was reduced to 8.93~24.12% in the presence of 25 ㎍/mL of MECR. The gingipain activity of Porphyromonas gingivalis were reduced to 3.91~6.23% in case of Kgp and 5.73~7.78% in case of Rgp in the presence of 10 mg/mL of MECR. The expression of fadA mRNA, virulence factor of Fusobacterium nucleatum (F. nucleatum) was 3 folds decreased in the presence of 25 ㎍/mL of MECR. In case of YD-38 cells challenged with F. nucleatum, RQ values of IL-8 and IL-6 were reduced about 12 folds and 5.45 folds in the presence of 2 ㎍/mL of MECR. In case of RAW 264.7 murine cell challenged with F. nucleatum, RQ values of IL-1β and IL-6 were 2.52 folds and 2.55 folds reduced in the presences of 2 ㎍/mL of MECR. Conclusively, MECR showed potent antibacterial and anti-inflammatory effects against oral pathogenic bacteria.

• The Journal of the Korean dental association
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• v.58 no.11
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• pp.683-689
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• 2020

Dentin surface of non-carious lesion is usually attached with oral biofilm. The biofilm should be removed before application of restorative material, because it may reduce the bond strength of adhesive system. The aim of this study was to evaluate the microtensile bond strength, when the biofilm was removed with brush or bur. Twenty extracted human third molars were sectioned horizontally to obtain dentin surface. Specimen were divided randomly into four group. Biofilm formation was performed in three group, except for Group 1 (negative control). Biofilm was removed as follows: Group 3, using ICB brush; Group 4, using lowspeed round bur #2. Group 2 (positive control) was not removed Biofilm. And in all four groups, the adhesive system (Optibond FL, Kerr) was applied to etched dentin surface, and resin composite was built up in three 1mm increments. After 24 hour storage in distilled water, the teeth were perpendicularly sectioned to obtain beams (1 × 1 mm2). Microtensile bond strength was measured and the data were statistically analyzed using one-way ANOVA and Tukey's post hoc test (p<0.05). Group 4 showed the highest microtensile bond strength (p<0.05), Group 3 showed no significant improvements when compared to Group 1. Group 2 showed lowest microtensile bond strength (p<0.05). When restoring a non-carious cervical lesion, it is essential to remove the biofilm present on the dentin surface. In addition, in the method of removing the biofilm, both the brush removal method and the bur removal method were effective.

• Journal of Korean society of Dental Hygiene
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• v.24 no.2
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• pp.131-139
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• 2024

Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheck^TM Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.284-292
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• 2016

Water supplied through dental unit waterlines (DUWLs) has been shown to contain high number of bacteria. To reduce the contamination of DUWLs, it is essential to develop effective disinfectants. It is, however, difficulty to obtain proper DUWL samples for studies. The purpose of this study was to establish a simple laboratory model for reproducing DUWL biofilms. The bacteria obtained from DUWLs were cultured in R2A liquid medium for 10 days, and then stored at $-70^{\circ}C$. This stock was inoculated into R2A liquid medium and incubated in batch mode. After 5 days of culturing, it was inoculated into the biofilm formation model developed in this study. Our biofilm formation model comprised of a beaker containing R2A liquid medium and five glass rods attached to DUWL polyurethane tubing. Biofilm was allowed to form on the stir plate and the medium was replaced every 2 days. After 4 days of biofilm formation in the laboratory model, biofilm thickness, morphological characteristics and distribution of the composing bacteria were examined by confocal laser microscopy and scanning electron microscopy. The mean of biofilm accumulation was $4.68{\times}10^4$ colony forming unit/$cm^2$ and its thickness was $10{\sim}14{\mu}m$. In our laboratory model, thick bacterial lumps were observed in some parts of the tubing. To test the suitability of this biofilm model system, the effectiveness of disinfectants such as sodium hypochlorite, hydrogen peroxide, and chlorhexidine, was examined by their application to the biofilm formed in our model. Lower concentrations of disinfectants were less effective in reducing the count of bacteria constituting the biofilm. These results showed that our DUWL biofilm laboratory model was appropriate for comparison of disinfectant effects. Our laboratory model is expected to be useful for various other purposes in further studies.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.149-157
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• 2022

The aim of this study was to evaluate the effects of erythrosine-mediated photodynamic therapy (PDT) on Streptococcus mutans biofilm recovery by counting its colony-forming units (CFUs) and via confocal laser scanning microscopy analysis at different time points following PDT. In PDT, photosensitizer was an erythrosine. S. mutans ATCC25175 biofilms were irradiated using an LED curing light. Chlorhexidine (CHX) was used as positive control. After each antimicrobial treatment, samples were cultured to allow biofilm recovery. Viability was measured by calculating the CFU counts after treatment and after every 3 hours for up to 24 hours. Immediately after treatment, the PDT and CHX groups showed equally significant decreases in S. mutans CFU counts compared to the negative control. After 12 hours of reculture, the PDT group showed no significant difference in the decrease in CFU count compared to the negative control, whereas the CHX group showed significantly lower CFU counts throughout the 24-hour period. Erythrosine-mediated PDT can effectively inhibit S. mutans biofilm formation. However, biofilm recovery occurred earlier in the CHX group after PDT. This study provides insights into the clinical effectiveness of PDT in preventing dental caries.