• Restorative Dentistry and Endodontics
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• 제17권1호
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• pp.115-125
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• 1992

It is advisable to use irrigation solutions which have strong antibacterial effect and weak cytotoxic effect on treating root infections. Streptococci are ones of the most frequently isolated microorganisms in infected root canals. The antibacterial effect of ten irrigation solutions were investigated on S. mutans (19449), S. sanguis. )10556) and 4 streptococci isolated from saliva of healthy persons. These streptococci were exposured to irrigation solutions during 10 sec, 30 sec,. 1 min, 3 min, 5 min, 10 min, 30 min and 2hrs respectively. Four irrigation solutions which showed strong antibacterial activity were diluted to 1 : 1 to 1 : 10,000. Then they were subcultured on blood agar plate an observed after 1 day. 5.25% NaOC1 had the strongest antibacterial effect. 30% urea and normal saline showed no antibacterial effect. 50 % citric acid and 3% $H_2O_2$ showed relatively weak antibacterial effect. 15 % EDTA had very weak antibacterial effect.

• 대한소아치과학회지
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• 제34권4호
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• pp.632-638
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• 2007

Xylitol 껌의 mutans streptococci(MS)에 대한 항균효과를 평가하기 위하여 6세${\sim}$11세 사이의 혼합치열기 어린이 62명을 선정하였다. 4개월 동안 1개의 xylitol 껌을 하루 3회 씹는군, 2개의 xylitol 껌을 하루 3회 씹는 군과 xylitol 껌을 씹지 않는 대조군으로 나누어 하루 3번 식후 최소 5분간 껌을 씹게 한 후 1개월 간격으로 자극성타액을 채취하여 선택배지(mitis salivarius kanamicin bacitracin agar)에 배양한 후 MS 군락 수의 감소를 평가하였다. 1회 1개의 xylitol 껌을 씹는 군에서는 MS의 감소를 보이지 않았고, 1회 2개의 xylitol 껌을 씹는 군에서 4개월째 MS의 유의한 감소를 보였다(P < 0.05). 따라서 혼합치열기 어린이의 경우 하루 3회, 총 10g 정도의 xylitol을 4개월 이상 꾸준히 사용하였을 경우 치아우식증에 대한 예방효과가 있을 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.577-609
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• 1995

Bacteria have been regarded as one of the most important factors in pulpal and periapical diseases. Streptococci are frequently isolated facultative anaerobes in infected root canals. Recently molecular biological techniques have been rapidly progressed. This study was designed to apply the molecular biological tools to the identification and classification of streptococci in the endodontic microbiology. Streptococci isolated from infected root canals were identified with both Vitek Systems and API 20 STREP. Identification results were somewhat different in several strains of streptococci. Eighteen streptococci and enterococcal was difficult so to digest plasmid DNA using Hind III and EcoRI to differentiate strains by restriction enzyme analysis of plasmid DNA. 16S rDNA of chromosome was amplified by polymerase chain reaction(PCR) and then restricition fragment length polymorphism(RFLP) using several restriction enzymes was observed. The molecular mass of 16S rDNA of chromosomal DNA was approximately 1.4kb. There were three to five RFLP patterns using eight restriction enzymes. RFLP patterns digested with CfoI which recognizes four base sequences were identical in all stains. Hind III which recognizes six base sequences could not digest the 16S rDNA. Restriction enzymes which recognize five base sequences were suitable for RFLP pattern analysis. At least three different restriction enzymes were needed to compare each strains. 16S rDNA PCR-RFLP was simple and rapid to differentiate and classify strains and could be used in the epidemiological study of root canal infections.

• 대한치과교정학회지
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• 제39권2호
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• pp.105-111
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• 2009

법랑질 탈회는 교정 치료 중에 발생하는 대표적인 부작용으로서 특히 교정용 브라켓에 대한 세균 부착이 그 원인이 될 수 있다. 본 연구의 목적은 서로 다른 표면 특성을 가진 세 종류의 브라켓을 구강 내 장착했을 때 각 재료의 표면에 대한 mutans streptococci 부착 정도를 측정하여 브라켓 재료에 따른 법랑질 탈회 및 치아 우식 발생 가능성을 분석하는 것이었다. 상하악 및 치아 부위별 mutans streptococci 부착 정도의 차이를 배제하고 브라켓 원재료에 따른 차이만을 검출하기 위하여 균형완전블록 실험계획을 설계하였다. 피실험자인 30세 여성의 구강 내에 장착할 수 있는 tooth positioner 형태로 3세트의 플라스틱 맞춤 트레이를 제작하였으며, 이 트레이에 직육면체의 형태($4{\times}3{\times}2\;mm$)로 제작한 stainless steel, monocrystalline sapphire, polycrystalline alumina 조각을 세트마다 서로 다른 순서로 전치부와 구치부 순면에 부착하였다 이렇게 제작된 3종류의 실험장치를 12시간 동안 피 실험자의 구강 내에 장착한 후, 각 브라켓 재료 표면에 형성된 치태를 채취하여 bacitracin이 포함된 mitis salivarius배지에서 48시간 배양 후 colony counting을 통해 그 표면에 부착된 mutans streptococci 양을 비교하였다. 이와 같은 방법으로 3세트의 실험장치에 대해서 각각 5회씩 총 15회의 실험을 시행하였다. 그 결과 상하악 및 치아 부위별 및 브라켓 재료별 세균 부착 정도는 모두 유의한 차이를 보이지 않았다. 결론적으로 본 연구의 결과 in vivo condition에서 브라켓 재료의 차이는 mutans streptococci 부착에 영향을 미치지 못하는 것으로 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제2권3호
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• pp.499-500
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• 1989

• 한국어병학회지
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• 제19권1호
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• pp.17-33
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• 2006

• Pediatric Infection and Vaccine
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• 제3권2호
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• pp.123-127
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• 1996

Purpose : The most patients with acute streptococcal pharyngitis lack of classic clinical manifestations, therefore diagnostic laboratory test such as the throat culture or a rapid antigen detection test are frequently employed in primary practices of developed countries. We'd like to know the accuracy of the throat swab culture as gold standard for diagnosis of streptococcal infection with studying the discordant and concordant rate of duplicate culture. Methods : The study included 89 normal school children (boys:50, girls:39) who were attending Uljin primary school in Uljin, Kyong Sang Buk Do on March 1996. We obtained simultaneous 2 times of throat swab from each subject, and plating and streaking on 5-7% of sheep blood agar separately. We counted the characteristic beta-hemolytic colonies after overnight incubation. Results : 1) The carrier rate of beta-hemolytic streptococci at first culture is 25.1% and second one is 29.2%. 2) Ten out of 89(11.2%) is discordant in duplicate culture. 3) Culture containing less than 50 colonies of beta-hemolytic streptococci (+2) in first culture is 70.4%, second one is 85.7%. 4) Number of colonies is less than 50 in all ten discordant children. Conclusions : The discordant rate of duplicate throat swab cullture for beta-hemolytic streptococci is 11.2%, even if the subjects are normal school children. About 5% of individuals harboring beta-hemolytic streptococci in the pharynx may be missed by a single throat culture. If we are trying to examine the patients with pharyngitis, the discordant rate will be much lower than this results.

• International Journal of Oral Biology
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• 제30권4호
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• pp.125-130
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• 2005

Thrombin-induced platelet microbicidal proteins (tPMP) are antibacterial proteins released when platelets are stimulated by thrombin. It has been reported that tPMP has antibacterial activity against various bacterial species including causative agents of infective endocarditis. Most of the oral streptococci have resistance to the killing by tPMP and this fact may play an important role as a virulence factor in infective endocarditis. However, the susceptibility and resistance mechanism of oral streptococci for tPMP have not been revealed yet. In this study, the killing mechanism of tPMP for oral streptococci has been investigated. Streptococcus rattus BHT, a susceptible strain, and Streptococcus gordonii DL1, a resistant strain, have been used in this study. tPMP was isolated from platelet after stimulation with thrombin. Cell membrane depolarization was examined with 3,3'-dipropylthiodicarbocyanine iodide ($DiSC_3$), membrane potential-sensitive cyanine dye, by fluorescence spectrophotometry. The permeabilization of cell membrane by tPMP was investigated with propidium iodide (PI) by flow cytometry. tPMP susceptible S. rattus BHT showed the increase of the $DiSC_3$ fluorescence level meaning depolarization of cell membrane and increase of the uptake of PI which means permeabilization of cell membrane. However, tPMP resistant S. gordonii DLI did not show depolarization and permeabilization. These results indicate that the increasing depolarization and permeabilization of oral streptococcal cell membrane are associated with the bactericidal activity of tPMP.

• 대한수의학회지
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• 제15권1호
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• pp.69-73
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• 1975

A Total of 173 streptococci isolated from 536 dairy cattle in Gyeonggi Province identified by Lancefield serological reaction and other biological properties. Antibiotics sensitivity test was also examined and the results obtained were as follows: 1. A total of 173 isolates of 167 strains (96.5%) were reacted with group A,B,C,D,E and G antisera. 2. Of the 167 positive strains, 75 strains were identified to Streptooccus uberis, 56 to Streptococcus agalactiage and 26 to Streptococcus dysgactiae, respectively. Also, Sreptococcus pyogenes, group D and group G streptococci were rarely isolated. 3. In results of antibiotic sensitivity tests, the most isolates were sensitive to leucomycin and erythromycin but less sensitive to streptomycin. and kanamycin.

• Journal of Nutrition and Health
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• 제31권3호
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• pp.305-314
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• 1998

Microflora in 14 breast-fed(BF) and 15 formula-fed(FF) infants were investigated before (2-3 months after birth) and after weaning (5-7 months birth) to find the floral differences between the two lactation groups and the floral changes after weaning. Bifidolbacteria showed the highest count among the species of microflora in the BF group before and after weaning, but in the FF group, streptococci showed the highest count before weaning and bifidobacteria after weaning. Before weaning , the count of bifidobacteria, lactobacilli and total acaerobes were significantly higher in the BF group than in the FF. However, the frequencies of clostridia and klesidella , along with the counts of streptococci and eubacteria, were higher in the FF group. After weaning , the only difference was that the total count of aerobic bacteria was higher in the BF group. The counts of streptococci in the BF group and lactobacilli and total anaerobes in the FF group after weaning were significantly higher than before weaning. However, the count of total aerobes in the FF group after weaning was significantly lower than the count before weaning.