• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.90-97
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• 2000

There are various kinds of factors associated with the formation of dental plaque in oral cavity such as nutrient molecules and chemical agents. The factors influencing the formation of insoluble glucan by Streptococcus sobrinus and its replication were examined on orthodontic wires. The results were as follows: 1. Insoluble glucan was well produced in the media initially adjusted at pH 7.0 than pH 5.5 or pH 8.5 like bacterial replication. 2. The synthesis of insoluble glucan and bacterial replication were significantly increased in the media containing 2.5% yeast extract. The formation of insoluble glucan was inhibited by 10 folds in the media containing 20% of sucrose than 1.25%, but the replication of bacteria was increased by 20 folds. 3. Insoluble glucan was significantly formed at a concentration of 1.0mM of calcium chloride, 40mM of potassium chloride, 0.1mM of magnesium chloride, while the replication of bacteria was little influenced by them regardless their concentration. 4. The formation of insoluble glucan and bacterial replication were significant in the media containing 10mM of sodium bicarbonate, but both were completely inhibited at 100mM or above. The production of insoluble glucan and the bacterial replication were largely decreased at 10mM of Tris while insoluble glucan was formed in abundance at 100mM of Tris. 5. The synthesis of insoluble glucan and the bacterial replication were inhibited at 10mM or above of sodium phosphate and potassium phosphate.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.466-472
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• 1999

The insoluble glucan is the major substance of dental plaque. In order to isolate the bacteria inhibiting the formation of insoluble glucan in disposable cuvette, saliva was got from about 10 thousand children. The isolated bacteria were tested by API 20S kit and API 50 CHL kit. These bactreia were identified as Streptococcus oralis, Streptococcus mitis, Streptococcus mitior, Streptococcus sanguis, Enterococcus durans, Lactococcus lactis, Lactobacillus acidophilus. When Streptococcus mutans was cultured with Streptococcus oralis, Streptococcus mitis, Streptococcus mitior, Streptococcus sanguis, Enterococcus durans, Lactococcus lactis, or Lactobacillus acidophilus in disposable cuvette, the optical density at 550 nm was 0.823, 0.912, 0.894, 0.878, 0.753, 0.845, 1.021 respectively, while being 1.503 in the disposable cuvette culturing Streptococcus mutans only.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.459-465
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• 1999

The inhibition degree of the isolated bacteria on plaque formation of Streptococcus mutans, and the effect of these bacterial genus on the concentration of total bacteria in saliva were assessed with the following. The effectiveness of the isolated bacteria on the inhibition of plaque formation was assessed culturing Streptococcus mutans in the beaker with orthodontic wires. The mean weight of plaque produced on a wire was 152mg in the culture of Streptococcus mutans only, whereas being reduced to 4mg, 78mg, or 72mg in the combined culture of Streptococcus mutans and Enterococcus durans, Lactobacillus acidophilus, or Streptococcus oralis. The colony forming units (CFU) of Streptococcus mutans were $3.6{\times}10^8$ per ml in the culture of Streptococcus mutans, only, wheras being $1.4{\times}10^6,\;5.6{\times}10^6,\;or\;3.8{\times}10^6$ per ml in the combined culture of Streptococcus mutans and Enterococcus durans, Lactobacillus acidophilus, or Streptococcus oralis. When saliva from children was inoculated on brain heart infusion agar, the colony forming units of bacteria were $4.8{\times}10^6\;to\;1.3{\times}10^9$ per ml of saliva. The concentration of Enterococcus, Lactobacillus, or Streptococcus inhibiting Streptococcus mutans in saliva was not proportioned to that of total bacteria replicated on brain heart infusion agar. These results indicate that the isolated bacteria inhibited the replication of Streptococcus mutans, resulting into inhibiting the formation of plaque, but the concentration of Enterococcus, Lactobacillus, or Streptococcus inhibiting Streptococcus mutans, in saliva might not affect the total bacterial concentration of saliva.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.314-322
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• 2004

The production of a glucan was affected by the concentration of ions and buffer solutions, and nutrients in an oral cavity. In this study, the effects of ions and buffer solutions on the mRNA expression of gtfD gene in Streptococcus mutans, an important causative agent of dental caries, were investigated by Fluorescent in situ hybridization(FISH). At first, ions and buffer solutions had little effect on the multiplication of Streptococcus mutans. The green fluorescence according to the mRNA expression of gtfD gene was detected in the BHI broth containing 1% sucrose. The intensities of the green fluorescence were strong at 0.25mM of $CaCl_2$. Little fluorescence was detected by the addition of KCl, except far 10mM KCl at which fluorescence intensities were similar to those of the control. Fluorescence intensities were weak at each concentration of $MgCl_2$ when compared to the control. As for buffer solutions, fluorescence intensities were similar to those of the control at each concentration of buffer solutions, except that they were little detected at 100mM of potassium phosphate.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.684-695
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• 2003

The aim of this study was to investigate the effect of composite resin components on proliferation and glucan synthesis by cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus. Light curing pit and fissure sealant was chosen for evluation. Specimens were eluted in deionized water for 10 minutes, 1, 12, and 24 hours. Extracts of specimens were diluted into 1/2, 1/4, and 1/8 with addition of BHI broth and BHI-YS. Bacteria were cultured in media included eluted components, and measured optical density($A_{600}$). The following results were obtained 1. 1/4 concentration of elutes for 10 minutes significantly inhibited the proliferation of S. mutans, whereas 1/2, 1/8 concentration of elutes stimulated it. Also, exacts, especially 1/2, 1/4 concentration, for 1 hours stimulated it. But exacts for 12, 24 hours had not effects on the proliferation of S. mutans. 2. 1/4 concentration of elutes for 10 minutes inhibited growth of S. sobrinus, whereas extracts for 1, 12, 24 hours had not effects on the proliferation of S. sobrinuss. 3. Extracts from composite resin stimulated total growth of S. mutans more than growth control group, where as inhibited it of S. sobrinus. 4. Extracts from composite resin, especially 1/4 concentration of it for 10 minutes increased the formation of water insoluble glucan of S. mutans. But elutes for 1, 12, 24 hours, and 1/8 concentration of it for 10 minutes inhibited it. 5. Except 1/4 concentration of elutes for 10 minutes, extracts decreased the formation of water insoluble glucan of S. sobrinus. 6. Total amount of formated glucan was 3-fold higher in S. mutans than in S. sobrinus.