• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.77-87
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• 1999

This study was performed to evaluate the effect of Streptococcus oralis on the formation of artificial plaque and the replication of Streptococcus mutans. S. mutans was incubated alone and in the combination with S. oralis in the beaker with wires. The produced plaque weight and the viable cells of S. mutans were compared between those cultures. Various factors were studied about the effect on the formation of plaque and the replication of S. mutans. Followings are the results. 1. Lower amount of plaque was produced and fewer cells of S. mutans were replicated at the mixed culture of S. mmutans and S. oralis than S. mutans alone. 2. When 10 mM glucose was added, the plaque weight was increased in the culture of S. mutans alone. But in the mixed culture of S. mutans and S. oralis, the plaque weight was not increased when 10 mM of glucose was added. 3. When 10 mM fructose was added, the plaque weight was increased in the culture of S. mutans alone or combined S. mutans and S. oralis. 4. In the mixed culture of S. mutans and S. oralis with different concentration, the more S. oralis exist, the less plaque and the fewer viable cells of S. mutans were observed. 5. The plaque weight and the viable cells of S. mutans were more decreased in the mixed culture of S. mutans and S. oralis than S. mutans alone after 12 hours. 6. When Staphylococcus epidermidis consuming hydrogen peroxide was added to the mixed culture of S. mutans and S. oralis, the plaque weight and the viable cells of S. mutans were increased. These results indicate that S. oralis inhibited the formation of plaque and the replication of S. mutans, and this may result from the formation of hydrogen peroxide S. oralis.

• Imaging Science in Dentistry
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• v.54 no.1
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• pp.43-48
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• 2024

Purpose: Oral hygiene, maintained through plaque control, helps prevent periodontal disease and dental caries. This study was conducted to examine the accuracy of plaque detection with an intraoral scanner(IOS) compared to images captured with an optical camera. Materials and Methods: To examine the effect of color tone, artificial tooth resin samples were stained red, blue, and green, after which images were acquired with a digital single-lens reflex (DSLR) camera and an IOS device. Stained surface ratios were then determined and compared. Additionally, the deviation rate of the IOS relative to the DSLR camera was computed for each color. In the clinical study, following plaque staining with red disclosing solution, the staining was captured by the DSLR and IOS devices, and the stained area on each image was measured. Results: The stained surface ratios did not differ significantly between DSLR and IOS images for any color group. Additionally, the deviation rate did not vary significantly across colors. In the clinical test, the stained plaque appeared slightly lighter in color, and the delineation of the stained areas less distinct, on the IOS compared to the DSLR images. However, the stained surface ratio was significantly higher in the IOS than in the DSLR group. Conclusion: When employing IOS with dental plaque staining, the impact of color was minimal, suggesting that the traditional red stain remains suitable for plaque detection. IOS images appeared relatively blurred and enlarged relative to the true state of the teeth, due to inferior sharpness compared to camera images.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.561-567
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• 2002

Xylitol is a 5-carbons carbohydrate, which can be replaced with sucrose for preventing caries. The replication of Streptococcus mutans and its formation of artificial plaque were studied in the media containing xylitol. The combined effect of xylitol and other carbohydrates on Streptococcus mutans was also studied. The replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol. Streptococcus mutans replicated at the initial stage of incubation in the media containing glucose, fructose or lactose, while replicating from the beginning of incubation in the media containing fructose as combining with xylitol. The formation of artificial plaque by Streptococcus mutans was significantly reduced in the media containing with xylitol and fructose. These results indicated that the replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol, and the formation of artificial plaque by Streptococcus mutans was significantly inhibited in the media containing xylitol and fructose.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.443-455
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• 2000

The aim of periodontal therapy is a removal of a bacterial plaque butthe instrumentation for plaque control has two nature : removal of a bacterial plaque and increase of surface roughness. Complication of instrumentation is enable to damage to the root surface and artificial crown. Therefore this study was conducted to evaluate the effects of repeated instrumentation on the marginal portion of artificial crown. Fifteen proximal surfaces of ten extracted periodontally diseased maxillary first molars were used. The finish line was placed on the root surface, and then the crown was casted and cemented in usual manner. Three kinds of instruments: hand curet, ultrasonic scaler, and ultrasonic curet were used. After instrumentation, final polishing was done with rubber cup and pumice. And surface changes were evaluated by stereomicroscope and scannig probe microscope. Roughness was increased after instrumentation in all groups, and was decreased after polishing except ultrasonic scaler group. Roughness in the ultrasonic scaler group was lower than others, and roughness after polishing in the hand curet group was lower than others. These results indicate that polishing procedure is recommended, because periodontalinstruments increase the surface roughness and induce the irreversible damage to the marginal portion.

• Journal of Korean society of Dental Hygiene
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• v.11 no.4
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• pp.465-474
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• 2011

Objectives : The removal of most reliable mechanical dental plaque that is to say tooth brushing was generalized to control of dental plaque, many oral health goods have also developed due to the effect differences followed by individual habit. The electric toothbrush have studied and developed widely as major field of study that electric toothbrush having various moving phase was sold and developed at the market. Methods : Accordingly author studied about selling electric toothbrushes shape (vibration type, ultra-sonic minuteness vibration type, semi rotation type) to raise the efficiency after comparing to the moving them that total 8 groups classified by poor tooth models for example normal set of tooth, crowding tooth, bracket attached tooth, prosthetic status etc. and executed plaque removal effect on the tooth through comparing experiment. Results : The removal rate of artificial plaque on the tooth was improved in proportion to the increase of tooth brushing time(p<0.05). The ultra-sonic minuteness vibration and semi rotation type was superior to toothbrush of vibration type comparing to the removal rate of plaque on the tooth(p<0.05). Conclusions : The electric toothbrush of supersonic minuteness vibration and semi rotation type can be recommended most of tooth types regardless of oral tooth setting status for example, normal set of tooth, crowding tooth, bracket attached tooth, porcelain tooth.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.549-557
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• 2000

Dental caries is a bacterial disease of the dental hard tisssus, characterized by a localized, progressive, molecular disintegration of tooth structure. The action of Leuconostoc lactis 51 about plaque formation and replication by Streptococcus mutans was studied as follows. 1. Lower amount of plaque was produced at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone on the wires in the beaker. 2. Fewer cells of S. mutans were replicated at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone. 3. In M17Y broth, viable cells of S. mutans and L. lactis 51 increased for 12 hours, and decreased for 24 hours. In M17YS broth, viable cells of S. mutans showed time-dependent decrease at mixed culture of S. mutans and L. lactis 51. 4. The culture supernatant of L. lactis 51 didn't inhibit the replication of S. mutans and the formation of artificial plaque. 5. Sucrose and frutose were extracted from the culture supernatant of L. lactis 51 in M17YS broth. These results suggest that L. lactis 51 isolated from the oral cavity inhibits the replication of S. mutans and the formation of artificial plaque.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.2
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• pp.449-459
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• 1997

The main component of dental plaque is the mutan containing the a-1,3 bond. The following results were obtained by using a blue mutan to assess the factors affecting the mutan-digesting activity of Streptomyces exfoliatus isolated from soil. A clear zone was produced by mutanase-producing Streptomyces exfoliatus on the minimal essential agar containing blue mutan. Streptomyces exfoliatus digested more blue mutan in the minimal essential broth at pH 7.0 than at pH 5.5 or 8.5. Streptomyces exfoliatus digested more blue mutan at $37^{\circ}C$ than at $32^{\circ}C$ or $42^{\circ}C$ (P<0.05). When the concentration of $CaCl_2$ was increased in the minimal essential broth, the digestion of blue mutan was increased (P<0.05). The optimal concentration of KCl was 10mM to digest blue mutan, but a similar amount of blue mutan was digested at the range of 0.1mM to 6.4mM of $MgCl_2$. When the culture supernatant of Streptomyces exfoliatus was mixed with 2X brain heart infusion broth containing 0.5% yeast extract and 10% sucrose, less artificial plaque was formed by Streptococcus mutans on the orthodontic wire (P<0.05). These results indicated that the secretion of mutanase was identified in culture supernatant of mutan-digesting Streptomyces exfoliatus, suppressing the formation of artificial plaque by Streptococcus mutans.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.15-23
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• 2000

Streptococcus salivarius is a normal inhabitant in the human oral cavity. Streptococcus salivarius 119 in this study was isolated from the oral cavity of child and identified, and its action mechanism on the formation of denal plaque by Streptococcus matans was studied. 1. The optical density of absorbance at 550 nm was 0.327 in the culture of Streptococcus mutans in disposable cuvette, whereas being 0.119 in the combined culture of Streptococcus mutans and Streptococcus salivarius 119. 2. The mean weight of produced artificial plaque on the wires in the beaker was 84.7mg in culture of Streptococcus mutans only, whereas being reduced to 12.3mg in the combined culture of Streptococcus mutans and Streptococcus salivarius 119. 3. When Streptococcus mutans was cultured in the media containing culture supernatant of Streptococcus salivarius 119 in BHI broth, the mean weight of produced artificial plaque was 100.5mg on the wires, whereas being reduced to 20.4mg in the media containing culture supernatant of Streptococcus salivarius 119 in BHIS broth. 4. The viable cells of Streptococcus oralis and Streptococcus salivarius 119 were $4.8\times10^7\;and\;7.5\times10^8$ per ml respectively after each culture, wheras being $4.2\times10^7\;and\;5.8\times10^7$ per ml in the combined culture of Streptococcus oralis and Streptococcus salivarius 119. 5. The polymer produced by Streptococcus salivarius 119 was glucan on the thin layer chromatography. 6. The glucan produced by Streptococcus salivarius 119 was water-soluble glucan containing $1\rightarrow6$ linkages as the main linkage on the thin layer chromatography. These results suggested that isolated Streptococcus salivarius 119 inhibited the formation of artificial plaque by the production of water-soluble glucan.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.7
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• pp.971-980
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• 2010

In this paper, an artificial neural network (ANN) was employed to build a predicting model for refrigerator structure. The predicting model includes three input variables of the plaque depth (D), width (W) and interval distance(S) on the inner wall. Finite element method was utilized to obtain the data, which would be necessary for the ANN training process. Finally, a genetic algorithm (GA) was applied to find the optimal parameters that leaded to the minimum inner case deformation under operating condition. The optimal combination found is the depth(D) of 2.63mm, the width(W) of 19.24mm and the interval distance(S) of 49.38mm which leaded to the smallest deformation of 1.88mm for the given refrigerator model.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.180-189
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• 2004

Chlorhexidine dihydrochloride and sodium fluoride have been used as agents inhibiting the replication of oral bacteria and the formation of dental plaque. There are various kinds of bacteria with different sensitivity against these agents. In this study, chlorhexidine dihydrochloride and sodium fluoride were studied about their effects on the replication of Streptococcus mutars, Streptococcus sobrinus, Streptococcus oralis and Streptococcus salivarius at their concentrations inhibiting the formation of artificial plaque by Streptococcus mutars. When Streptococcus mutans was cultured for 8 hours in the media added with $1.0{\mu}M$ chlorhexidine dihydrochloride, the weight of formed artificial plaque was decreased to $5.1{\pm}1.5mg$ compared with $106.1{\pm}18.1mg$ of the control(p<0.05). At the same time, the optical density of cultured media was decreased. The optical density of cultured media was slightly decreased in Streptococcus sobrinus, but was not decreased in Streptococcus oralis. The optical density of Streptococcus salivarius was decreased at 8 hours-incubation, was not decreased at 24 hours-incubation. When Streptococcus mutars was cultured for 8 hours in the media added with 3.0 mM sodium fluoride, the weight of formed artificial plaque was decreased to $26.7{\pm}8.3mg(p<0.05)$. At the same time, the optical density of cultured media was decreased. The optical density of cultured media was decreased in Streptococcus sobrinus and Streptococcus oralis, but was slightly decreased in Streptococcus salivarius. These results suggest that at the concentration of chlorhexidine dihydrochloride and sodium fluoridehe inhibiting the formation of artificial plaque by Streptococcus mutans, different species of genus Streptococcus show the different sensitivity against these agents.