• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.73-82
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• 2008

Dental caries is an infectious disease caused by mutans streptococci, and is a primary etiologic agent of dental caries in humans. The molecular pathogenesis of mutans streptococcal-associated dental caries occurs in three phases. Firstly, S. mutans attaches to tooth surface via a cell surface adhesion termed antigen I/II. In the second phase, the glucosyltransferase(GTFs) synthesize polymers like glucans in the presence of sucrose. In the third phase, the multivalent glucans interacts with glucan binding proteins (GBPs) and they make dental plaque and accumulation of microorganisms. Many studies and clinical trials have indicated that a mucosal immune response to these antigens(Ag I/II, GTFs, GBPs) of S. mutans can influence the pathogenesis of dental caries. So these antigens can be important vaccine candidates for immunologic intervention against dental caries. In this study, we cloned the genes for GTFb, GTFc, GTFd from S. mutans GS-5 and did the nucleotide sequence analysis. And the recombinant proteins of GTFd and N-terminus of GTFd were expressed. Intact GTF which we get from this experiment can be used for antibody production specific for any GTF activity domain through animal experiment.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.70-77
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• 2020

The present study is aimed to assess the effect of antimicrobial photodynamic therapy (aPDT) on Streptococcus mutans biofilm through teeth whitening light emitting diode (LED). Planktonic and dynamic biofilm state cultures of S. mutans were used. Erythrosine 20 μM/L was used as the photosensitizer. Irradiation was performed by exposing cultures to clinic and homecare whitening LEDs for 15 minutes. The viability was measured through Colony Forming Unit counts and confocal laser scanning microscopy. aPDT using whitening LEDs and erythrosine significantly decreased the CFU count of S. mutans compared to that in the control group. Dynamic biofilm group showed more resistant features to aPDT compared with planktonic state. Clinic and homecare whitening LED device showed similar antimicrobial effect. The whitening LED, which could irradiate the entire oral arch, showed a significant photodynamic effect on cariogenic S. mutans biofilm. aPDT mediated by erythrosine and LEDs used for teeth whitening exhibited promising antimicrobial activity.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.257-265
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• 2020

This study was performed to evaluate the restoration combined with resin infiltration (RI) of early cavitated smooth surface caries lesion in terms of microleakage. Flowable resin and resin-modified glass ionomer cement (RMGIC) were compared. Sound 20 extracted 3rd molars were divided into 2 groups randomly. Artificial decalcified lesion was induced. Cavities were prepared on the mesial and distal surfaces, and randomly set as experimental and control group. RI was applied to the experimental group before cavity restoration. The control group was restored without RI. In group I and II, flowable resin and RMGIC was used for restoration respectively. After thermocycling and silver nitrate immersion, microleakage was assessed by μ-CT. Depth of microleakage was lower in experimental group than control group only in group II (p = 0.05). Microleakage depth was lower in group II than group I in both experimental and control groups (p = 0.05). RI pretreatment before restoration of early cavitated caries lesions might reduce the microleakage and help long-term maintenance of restoration. In this study, RMGIC was less polymerization shrinkage. Restoration with RMGIC after RI pretreatment reduced the microleakage of the restoration compared to the flowable resin.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.397-405
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• 2020

The aim of this study is to compare cariogenic characteristics of fluoride-sensitive Streptococcus mutans [fluoride-sensitive (FS) S. mutans ] and fluoride-resistant Streptococcus mutans [fluoride-resistant (FR) S. mutans] in the presence of sucrose, and to evaluate its effect on cariogenic biofilm formation. S. mutans ATCC 25175 was continuously cultured in trypticase soy broth (TSB) containing NaF (70 ppm) for 40 days to generate FR S. mutans. FS and FR S. mutans were inoculated in TSB with or without 2% sucrose, and optical density and pH were measured every hour. An oral biofilm was formed using saliva bacteria and analyzed through confocal laser scanning microscopy and CFU count. Finally, the expression of glucosyltransferases genes of both S. mutans was investigated through RT-PCR. FR S. mutans exhibited slower growth and lower acidogenicity in the presence of sucrose compared to FS S. mutans . Both cariogenic and single species biofilm formation was lower in the presence of FR S. mutans, along with reduced number of bacteria. FR S. mutans showed significantly low levels of gtfB, gtfC, and gtfD expression compared to FS S. mutans . On the basis of results, FR S. mutans may be less virulent in the induction of dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.600-606
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• 2002

The purpose of this study was to evaluate the diagnostic validity of an incipient occlusal caries using argon laser fluorescence. Extracted human premolars and molars with enamel carious lesion of occlusal surface were assessed using visual examination, visual examination with probing, argon laser fluorescence and histologic depth of carious lesion. The results in each of all the three detection methods were compared to the assessment of histologic depth of carious lesion using polarized microscope. The results from the present study can be summarized as follows; 1. There was highly correlation between the histologic depth of occlusal caries and all three detection methods(P<0.01). 2. The reproducibility(kappa value) of the visual examination, visual examination with probing and argon laser fluorescence between the histologic depth of occlusal caries was 0.189, 0.128, 0.472. The highest correlation was seen between detection of occlusal caries by argon laser fluorescence and histologic scores by polarized microscope. The results from this study indicated that argon laser fluorescence considered to be accurate and reliable method in detecting occlusal caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.539-549
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• 2009

The purpose of this study was to investigate the prevalence of dental caries, periodontal status, and self-perceived oral health status of students in juvenile protection education institutions. The subjects of this study were 342 adolescents aged 13-20 years detained in two juvenile protection education institutions located in Gyeonggi Province. The study involved an oral examination to record decayed, missing, filled teeth and index teeth with bleeding, calculus, or periodontal pocket, combined with a questionnaire to investigate self-perceived oral health status. The main findings are as follows. 1. When compared with the result of National oral health survey, the students detained had more decayed teeth, DMFT, and teeth with bleeding, calculus, and shallow pocket than general population of the same age. 2. Female students showed more DMFT, more teeth with healthy periodontium, and fewer teeth with shallow pocket than male students (p<0.05). 3. Female students perceived their health to be poorer than male students (p<0.05). A majority(79.2%) of detainee valued their oral health in their life. 4. A majority(71.5%) of detainee reported their dental anxiety, and more female adolescents showed dental anxiety than male adolescents(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.522-530
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• 2009

The purpose of this study was to evaluate the clinical effectiveness of new streptococcus detection system which used monoclonal antibody against Streptococcus mutans. 92 children aged between 2 and 8 were involved in this experiment and their saliva samples were collected for testing. Streptococcus mutans were measured by both monoclonal antibody-based detecting system (Saliva-$check^{TM}$ Mutans) and dip slide detecting system($Dentocult^{TM}$-SM). The results showed that Saliva-$check^{TM}$ Mutans levels had a significant correlation with dfs rate of subjects and the two test kits, Saliva-$check^{TM}$ Mutans and $Dentocult^{TM}$-SM were shown to have a good correlation although they were based on different mechanism.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.130-139
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• 2007

This study investigated the relationship between dental caries and various oral factors in subjects with Down's syndrome. We compared 25 subjects with Down's syndrome with 63 healthy control. The dental caries index and plaque index were examined, and the total salivary immunoglobulin A and S. mutans specific salivary immunoglobulin A concentration were measured using ELISA. The S. mutans counts, Lactobacillus counts and buffer capacity were measured with Dentocult test medium. The decayed and filled surface index of deciduous teeth in subjects with Down's syndrome was lower than in controls(p<0.001). The plaque index and total salivary immunoglobulin A concentration showed no difference, S. mutans specific salivary immunoglobulin A concentration and buffer capacity in subjects with Down's syndrome were lower than in controls(p<0.001). There was no significant difference between two groups in the S. mutans counts and Lactobacillus counts. In 9-11 year age group, S. mutans counts in subjects with Down's syndrome was lower than in controls(p<0.001) and S. mutans specific salivary immunoglobulin A concentration was lower(p<0.05). There was a high correlation among deciduous dental caries index and buffering capacity and S. mutans counts.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.199-205
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• 2012

Although the stainless steel crowns have been recognized as the most effective and durable form of restoration for primary molars, they have been regarded by many dentists as having definite demerits such as invasive nature of procedural complexity and behavioral aspects of children. As an alternative to conventional technique of stainless steel crown restoration, the Hall technique was first introduced in 1988, which is characterized by just pushing the pre-contoured, cement filled crown form onto the abutment molar with no local anesthesia, no caries removal, no tooth preparation. According to several reports, this can slow, arrest, or even reverse the progress of caries. In addition, its atraumatic feature gives less discomfort and stress to children than conventional one, which is thought excellent especially in younger children. Also, It has been reported to be effective and acceptable to dentist, child patients and their parents. In this case study, three children with age of 4 years 5 months, 4 years 10 months, 6 years 4 months were treated with stainless steel crowns using Hall technique on first primary molar respectively. The teeth were free from pulpal, periapical pathology. After follow up of about 3 to 6 months period, the results showed clinically successful outcomes without any marked complication in pulp, tooth or soft tissue till now. But, it should be kept in mind that this technique is not proper to every child, every carious molar, or every dentist. Thorough distinction of indicated cases and continuous follow-up check is highly required. Conclusively, Hall technique might be an effective and realistic minimally invasive alternative for the carious primary molars especially in younger or disabled children, despite potential doubts on its efficacy and some definite limitations.

• Journal of dental hygiene science
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• v.2 no.2
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• pp.115-119
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• 2002

This study was carried out to evaluate the status of oral health in physically or mentally handicapped students. The status of oral health in 597 handicapped students of six special education institutes and 731 normal students in Chonbuk province were inspected by a dental hygienist from August to November of 1999. 1) The DT index(Decayed Teeth index) was significantly higher in handicapped students comparing with those of normal students. The proportions of children having gingivitis and malocclusion were also significantly higher in handicapped group (p<0.01). 2) The incidences of dental caries, gingivitis and malocclusion were significantly higher in mentally retarded students comparing with those of physical or sensory impairment groups(p<0.01). 3) Handicapped students participating in the regular school teeth-control program showed significantly low incidences of gingivitis and malocclusion comparing with non-participants. However, dental caries had no relationships with teeth control program. There were no differences between commuting and domitory-resident students in the incidences of dental caries, gingivitis and malocclusion.