• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.17-20
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• 2002

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.5-8
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• 2002

• Restorative Dentistry and Endodontics
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• v.40 no.3
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• pp.195-201
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• 2015

Objectives: The use of chitosan nanoparticles (CNPs) in endodontics is of interest due to their antibiofilm properties. This study was to investigate the ability of bioactive CNPs to remove the smear layer and inhibit bacterial recolonization on dentin. Materials and Methods: One hundred bovine dentin sections were divided into five groups (n = 20 per group) according to the treatment. The irrigating solutions used were 2.5% sodium hypochlorite (NaOCl) for 20 min, 17% ethylenediaminetetraacetic acid (EDTA) for 3 min and 1.29 mg/mL CNPs for 3 min. The samples were irrigated with either distilled water (control), NaOCl, NaOCl-EDTA, NaOCl-EDTA-CNPs or NaOCl-CNPs. After the treatment, half of the samples (n = 50) were used to assess the chelating effect of the solutions using portable scanning electronic microscopy, while the other half (n = 50) were infected intra-orally to examine the post-treatment bacterial biofilm forming capacity. The biovolume and cellular viability of the biofilms were analysed under confocal laser scanning microscopy. The Kappa test was performed for examiner calibration, and the non-parametric Kruskal-Wallis and Dunn tests (p < 0.05) were used for comparisons among the groups. Results: The smear layer was significantly reduced in all of the groups except the control and NaOCl groups (p < 0.05). The CNPs-treated samples were able to resist biofilm formation significantly better than other treatment groups (p < 0.05). Conclusions: CNPs could be used as a final irrigant during root canal treatment with the dual benefit of removing the smear layer and inhibiting bacterial recolonization on root dentin.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.186.1-186
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• 1998

No Abstract, See Full Text

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2002.04a
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• pp.87-88
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• 2002

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.228-235
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• 2015

Stream ecosystems are closely related to many human activities. Therefore, streams are affected by anthropogenic disturbances such as riverine development and gravel-mining as well as deterioration of water quality. The goal of this study was to elucidate the recolonization process of the macroinvertebrate community after a small-scale anthropogenic disturbance. Field studies were conducted at three sites in a natural stream. The number of recolonizing species tended to increase slightly over time, exceeding the total species number of the control. Ephemeroptera contributed the most to shaping the recolonizing pattern of the entire community. From the result of changes in dominant species, the early recolonizers of each site were the species that showed more frequent occurrence particulary at each sites. But the late recolonizers are Chironomidae at all the sites commonly. This result implies that the actual differences exist among the recolonizing trends of each benthic macroinvertebrate taxon. Collector-gatherers and scrapers comprised about 70% of the recolonizing species. These results indicate that the recolonizing process of an aquatic community after an artificial disturbance depends on the environmental conditions(particularly substratum composition or organic pollution) of the habitat.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.259-271
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• 2014

This study was conducted to investigate the impact of sand addition to an intertidal for the development of the Manila clam habitat on benthic community structure. For this, we focused on the spatio-temporal changes in the surface sediment condition and benthic community structure including Manila clam before and after the event. Study site was the lower part of Ojjeom tidal flat in Gonam-myeon, Taean-gun where sand added to on July 2010. We set three stations at each of sand adding area (experimental plot) and non sand-adding area (control plot) and did sampling works ten times from June 2010 to October 2011. Directly after the event, surface sediments changed to very coarse sand, but the state was not maintained over two months because of seasonal sedimentation and finally got back to the original grain sizes in eight months. The number of species and density were temporarily reduced right after the event and polychaetes such as Sternaspis scutata, Ampharete arctica were most negatively affected by the event. However, the number of species and density quickly recovered from the reduction in four to six weeks owing to the recolonization by the existing species and species in the vicinity of the plot. However, despite the recovery of ecological indies, species composition was continuously changed from one to another, thereby community structure stayed unstable condition, especially in some stations with finer sediment in their original condition. After sand addition, density of Manila clam was prominently increased at only one station with coarser sediment in its original condition.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.483-492
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• 1994

The purpose of this study was to assess the recolonization of the subgingival microflora following scaling and root planing on single and multiroot teeth with periodontal pockets which were above 5mm. 7 patients with deep pockets were selected for this study. They had not taken antibiotics for 6 months and no history of dental treatment for 6 months before the study. After initial clinical(plaque index, gingival index, probing pocket depth), microbiological and BANA test were determined, each subject received a single session of scaling and root planing, but they were not received oral hygiene instructions. Clinical indices, microbial parameters and BANA test were reassessed 1, 2, and 4 weeks after treatment. The results were as follows : 1. Plaue index, gingival index and pocket depth were not significantly when compared single root group with multiroot group, both groups were siginficantly reduced at 2weeks in plaque index and 2, 4 weeks in gingival index(P<0.05), probing pocket depth was siginificantly changed at 2, 4weeks in multiroot teeth group and 4 weeks in single root teeth group(P<0.05). 2. Percentage of cocci was significantly increased at 4weeks in single root teeth group(P<0.05), motile rod was significantly changed at 4weeks in both group(P<0.05), spirochetes and nonmotile rods were not significantly changed. 3. BANA test was significantly reduced at 1 and 2 weeks (P<0.05) in single root teeth group, multiroot teeth group was not significantly all weeks. This results were suggested that clinical and microbiological effect following scaling and root planing on periodontal disease.

• Journal of Periodontal and Implant Science
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• v.51 no.3
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• pp.199-212
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• 2021

Purpose: This randomized clinical placebo-controlled trial was conducted to evaluate the effectiveness of Lactobacillus reuteri as a probiotic in guided pocket recolonization (GPR) for the treatment of chronic periodontitis (CP) adjunctive to scaling and root planing (SRP). Methods: Forty-eight CP patients were randomly assigned to 3 treatment groups: group 1 (SRP+placebo), group 2 (SRP+single application of probiotic), and group 3 (SRP+incremental application of probiotic). Clinical parameters were evaluated at baseline and at 8, 12, and 24 weeks, whereas biochemical parameters were measured at baseline and 12 weeks. Results: At 24 weeks, the probing pocket depth and clinical attachment level improved in all 3 groups from baseline with no significant intergroup differences; however, a statistically significant difference was observed in localized plaque and gingival scores between groups 1 and 3 (P<0.05). At 12 weeks, matrix metalloproteinase-8 (MMP-8), nitric oxide (NO), and gingipains-R (Rgps) levels improved in all 3 groups, with statistically significant differences between groups 1 and 3 for MMP-8 and NO (P<0.05), but no difference for Rgps levels. Conclusions: Within its limitations, the results of this study show that incremental 3-time application of L. reuteri as a probiotic led to improvements in clinical and biochemical parameters. This protocol can be a useful adjunct to SRP in the non-surgical management of CP.

• The Korean Journal of Ecology
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• v.8 no.3
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• pp.141-146
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• 1985

Colonization ability was studied with Lemna paucicostata and Spirodela polyrhiza. Colonization ability of each species was defind as its ability to; (1) tolerate to desiccation, (2) multiplicate and spread in the new habitat, (3) inhibit the other species competitively. Lemna paucicostata was inferior to Spirodela polyrhiza in ability (1), but superior to Spirodela polyrhiza in abilities (2) and (3). Whenever lemna paucicostata and Spirodela polyrhiza are colonized recently, only these three abilities can not explain which species is better colonist. Even short unsuitable periods would eliminate a species, with time lag occurring before recolonization. This would result in a discontinuous of the species concerned.