• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.1
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• pp.21-28
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• 2017

Background: The skin consists of tightly connected keratinocytes, and prevents extensive water loss while simultaneously protecting against the entry of microbial pathogens. Excessive cellular levels of reactive oxygen species can induce cell apoptosis and also damage skin integrity. Propofol (2,6-diisopropylphenol) has antioxidant properties. In this study, we investigated how propofol influences intracellular autophagy and apoptotic cell death induced by oxidative stress in human keratinocytes. Method: The following groups were used for experimentation: control, cells were incubated under normoxia (5% $CO_2$, 21% $O_2$, and 74% $N_2$) without propofol; hydrogen peroxide ($H_2O_2$), cells were exposed to $H_2O_2$ ($300{\mu}M$) for 2 h; propofol preconditioning (PPC)/$H_2O_2$, cells pretreated with propofol ($100{\mu}M$) for 2 h were exposed to $H_2O_2$; and 3-methyladenine $(3-MA)/PPC/H_2O_2$, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to $H_2O_2$. Cell viability, apoptosis, and migration capability were evaluated. Relation to autophagy was detected by western blot analysis. Results: Cell viability decreased significantly in the $H_2O_2$ group compared to that in the control group and was improved by propofol preconditioning. Propofol preconditioning effectively decreased $H_2O_2$-induced cell apoptosis and increased cell migration. However, pretreatment with 3-MA inhibited the protective effect of propofol on cell apoptosis. Autophagy was activated in the $PPC/H_2O_2$ group compared to that in the $H_2O_2$ group as demonstrated by western blot analysis and autophagosome staining. Conclusion: The results suggest that propofol preconditioning induces an endogenous cellular protective effect in human keratinocytes against oxidative stress through the activation of signaling pathways related to autophagy.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.69-79
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• 2003

The purpose of this present study was to develop a new way of self-curing acrylic resin, using commercially available polyphosphate, Calgon, which is known to be antimicrobial and safe. For the study, polyphosphate(polyP) was blended with acrylic powder and devided into four groups as follows: no polyP(control), 1% polyP, 2% polyP, and 3% polyP. For the experiment, Streptococcus mutans GS5, Streptococcus sobrinus 6715, Streptococcus gordonii G9B and Challis, Porphyromonas gingivalis 2561, and Candida albicans ATCC 90027 were used. Resin specimens in each group were tested in vitro for the purpose of investigating the effect of polyP on the microbial attachment, growth and hydrophobicity of the resin surface. The results were as follows. 1. PolyP added to the acrylic resin decreased attachment of S. mutans GS5, S. sobrinus 6715, S. gordonii G9B. The greater binding inhibition was found in acrylic resin polymerized with polyP at higher concentrations. 2. The addition of polyP to acrylic resin failed to significantly affect the growth of the tested microorganisms. 3. The addition of polyP to acrylic resin seemed to reduce hydrophobicity of the acrylic resin. PolyP in acrylic resin does not seem to exert a direct antibacterial activity, but rather inhibit attachment of oral bacteria, especially mutans streptococci to saliva-coated acrylic resin. The acrylic resin reduces attachment of streptococci may be due to the decreased hydrophobicity caused by polyP added to the resin. PolyP may be included to acrylic resin to inhibit dental caries which often occurs when removable acrylic resin appliance is placed.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.247-254
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• 2007

Mutans streptococci have been reported to be implicated in dental caries. Of these streptococcal species, Streptcoccus mutans and Streptococcus sobrinus are most commonly found in human dental caries. Prevalence of these bacterial species in dental caries is found to be varied in different races and countries. Therefore, importance of these bacteria in dental caries remains to be determined The present study was performed to find out correlation S. mutans and S. sobrinus with dental caries in 125 Korean children with mixed dentition between 6 to 11 years of age. They were classified as group A(6-8 years) and group B(9-11 years) by age. For the study, stimulated saliva samples were collected from each subject. The vials containing saliva specimens were serially diluted (1:10) in saline and plated in duplicate on tryptone-yeast extract-cysteine with sucrose and bacitracin (TYCSB) for S. mutans and S. sobrinus. After genomic DNA was extracted from the samples, polymerase chain reaction (PCR) amplification was performed for identification using universal primers and specific primers to S. mutans and S. sobrinus. Data of microbial variables were compared to caries status of the subjects. According to this study, the result were as follows : 1. S. mutans versus S. sobrinus were moderate positive linear correlated in both group A(r=0.70) and group B(r=0.50). 2. Between S. mutans and dental caries there were weak positive linear correlation in both group A(r= 0.25) and group B(r=0.34). 3. S. sobrinus versus dental caries were not correlated in group A but slightly correlated in group B(r=0.21). 4. Between S. mutans and age, there were not correlation in both group. 5. S. sobrinus versus age were weak correlated in group A(r=0.32) but not correlated in group B.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.500-506
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• 2005

This study was carried out to obtain knowledges on the survival of Streptococcus mutans in the yoghurt added with green tea powder. The growth inhibition of green tea powder on the food borne pathogens and oral bacteria was measured by total microbial count, Among the tested food borne pathogens, the growth of Staphylococcus aureus and Salmonella enteritidis were not significantly affected by the addition of green tea powder, but green tea powder showed the growth inhibition effect on Escherichia coli O157:H7. The number of surviving Streptococcus mutans cell was decreased by $0.56\~0.99log$ cycle after 24 hem incubation by the addition of $0.5\~2.5\%$ green tea powder in the medium. And also the viable cell count of surviving Streptococcus mutans cells (initial inoculum $3.4\times10^7CFU/mL$) were decreased to $1.4\times10^4\~7.2\times10^4 CFU/mL$ after 48 hours incubation when $0.5\~2.5\%$ green tea powder were added to the drinkable yoghurt, Growth of Streptococcus mutans was strongly inhibited by the addition and incubation of green tea powder for 48 hum in the yoghurt.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.143-152
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• 2008

Purpose: Specific bacteria are believed to play an important role in chronic periodontitis. Although extensive microbial analyses have been performed from subgingival plaque samples of periodontitis patients, systemic analysis of subingival microbiota has not been carried out in a Korean population so far. The purpose of this study was to investigate the prevalence of 29 putative periodontal pathogens in Korean chronic periodontitis patients and evaluate which pathogens are more associated with Korean chronic periodontitis. Material and Methods: A total of 86 subgingival plaque samples were taken from 15 chronic periodontits(CP) patients and 13 periodontally healthy subjects in Korea. CP samples were obtained from the deepest periodontal pocket (>3 mm probing depth[PD]) and the most shallow periodontal probing site ($\leq$3 mm PD) in anterior tooth and posterior tooth, respectively, of each patient. Samples in healthy subjects were obtained from 1 anterior tooth and 1 posterior tooth. Polymerase chain reaction (PCR) of 16S ribosomal DNA (rDNA) of subgingival plaque bacteria was performed. Detection frequencies(% prevalence) of 29 putative periodontal pathogens were investigated as bacterium-positive sites/total sites. Results: With the exception of Olsenella profuse and Prevotella nigrescens, the sites of diseased patients generally showed higher prevalence than the healthy sites of healthy subjects for all bacteria analyzed. Tanerella forsythensis (B.forsythus), Campylobacter rectus, Filifactor alocis, Fusobacterium nucleatum, Porphyromonas endodontalis and Porphyromonas gingivalis were detected in more than 80% of sites with deep probing depths in CP patients. In comparison between the sites (deep or shallow PD) of CP patients and the healthy sites of healthy subjects, there was statistically significant difference(P<0.05) of prevalence in T.forsythensis (B.forsythus), C.rectus, Dialister invisus, F.alocis, P.gingivalis and Treponema denticola. Conclusion: Our results demonstrate that the four putative periodontal pathogens, T.forsythensis (B.forsythus), C.rectus, P.gingivalis and F.alocis are closely related with CP patients in the Korean population.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.46-50
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• 2015

Both Portulaca oleracea (PO) and Glechoma hederacea (GH) have been used as traditional medicine due to the multiple pharmacological activities. However, the effects of PO and GH in the pathology of periodontitis is still elusive. In this study, we examined anti-microbial activity of PO ethanol extract (POEE) and GH ethanol extract (GHEE) in vitro, and physiological effects of POEE and GHEE on the cell inflammatory responses and the severity of periodontitis were determined using the rat periodontitis model. Our results indicate that POEE and GHEE had no effects on the proliferation of streptococcus mutans and on LPS-mediated inflammatory responses in gingival fibroblast cells. Notably, ingestion of POEE and GHEE resulted in attenuating the severity of periodontitis and population change of immune cells. These data suggests that PO and GH should be considered as candidates for relieving the severity of periondontitis.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.340-348
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• 2015

Peri-implantitis is the most common reason for a late failure and can occur even after years of successful osseointegration. The role of microbial plaque accumulation in the development of peri-implantitis has been well documented. On the other hand, the ideal method of implant surface decontamination to re-establish the health of peri-implant tissue remains to be determined. Removal of bacterial deposits is essential in the treatment of peri-implant infections, and various therapeutic approaches have been described in the literature, including mechanical debridement, disinfection with chemotherapeutic agents, and laser therapy. Recently, there has been a plenitude of scientific data regarding the use of laser irradiation to achieve titanium surface decontamination. Thus, research is focusing on lasers' potential use in the treatment of peri-implantitis. The aim of this literature review is to analyze and evaluate the efficacy of laser therapy for the treatment of peri-implantitis.

• Proceedings of the KACD Conference
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• 2002.11a
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• pp.720-720
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• 2002

A number of investigations have shown that the presence of bacteria is prerequisite for developing pulpal and/or periradicular pathosis. Depending on the stage of pulpal pathosis, various species of bacteria can be cultured from infected root canals. Kakehashi et al. showed that exposure of pulpal tissue in germ-free rats was characterized by minimal inflammation and dentinal bridging while exposure of pulpal tissue in conventional rats with normal oral flora was characterized by pulpal necrosis, chronic inflammation, and periapical lesions. Currently used methods of cleaning and shaping, especially rotary instrumentation techniques, produce a smear layer that covers root canal walls and the openings to the dentinal tubules. The smear layer contains inorganic and organic substances that include fragments of odontoblastic processes, microorganisms, their by products and necrotic materials. Because of its potential contamination and adverse effect on the outcome of root canal therapy, it seems reasonable to suggest removal of the smear layer for disinfection of the entire root canal system. Presence of this smear layer prevents penetration of intracanal medications into the irregularities of the root canal system and the dentinal tubules and also prevents complete adaptation of obturation materials to the prepared root canal surfaces. Removal of the smear layer by an intracanal irrigant and placement of an antibacterial agent in direct contact with the content of dentinal tubules should allow disinfection of this complex system and better outcome for the root canal therapy. A new solution, which was a mixture of a tetracycline, an acid, and a detergent(MTAD), was developed in the Department of Endodontics, Dental School. Lorna Linda University, USA. It has been demonstrated that MTAD was an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when used as a final irrigant in conjunction with 1 % NaOCl as a root canal irrigant. Studies are in progress to compare the anti- microbial properties of this newly developed solution with those of sodium hypochlorite and EDTA that are currently used to irrigate the root canals and remove the smear layer from the surfaces of instrumented root canals.canals.

• The korean journal of orthodontics
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• v.47 no.1
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• pp.3-10
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• 2017

Objective: Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods: AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results: SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions: Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial.

• Food Science of Animal Resources
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• v.40 no.4
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• pp.541-550
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• 2020

The use of yeast assist kefir fermentation, but also can cause food spoilage if uncontrolled. Hence, in this study, the microbial composition of an existing commercial kefir starter was modified to produce a functional starter, where Lactobacillus acidophilus KCNU and Lactobacillus brevis Bmb6 were used to replace yeast in the original starter to produce non-yeast kefir-like fermented milk. The functional starter containing L. acidophilus KCNU and L. brevis Bmb6 demonstrated excellent stability with 10¹⁰ CFU/g of total viable cells throughout the 12 weeks low-temperature storage. The newly developed functional starter also displayed a similar fermentation efficacy as the yeast-containing control starter, by completing the milk fermentation within 12 h, with a comparable total number of viable cells (10⁸ CFU/mL) in the final products, as in control. Sensory evaluation revealed that the functional starter-fermented milk highly resembled the flavor of the control kefir, with enhanced sourness. Furthermore, oral administration of functional starter-fermented milk significantly improved the disease activity index score by preventing drastic weight-loss and further deterioration of disease symptoms in DSS-induced mice. Altogether, L. acidophilus KCNU and L. brevis Bmb6 have successfully replaced yeast in a commercial starter pack to produce a kefir-like fermented milk beverage with additional health benefits. The outcome of this study provides an insight that the specific role of yeast in the fermentation process could be replaced with suitable probiotic candidates.