• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.240-246
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• 2012

It's basically meant to make a contribution to the promotion of the oral health of shipbuilding workers and to the improvement of oral health education planning, industrial oral health policy setting and the related system, as it seems that the working environments of shipbuilding workers are very harsh due to the unique characteristics of their working process. The subjects in this study were the workers who were selected by convenience sampling from shipbuilding companies and their subcontractors in South Jeolla Province that numbered 10. The workers were surveyed to determine the relationship between their oral health education experience and oral health awareness, and the findings of the study were as follows: Out of the 310 workers investigated, 89.4 percent had no experience to receive oral health education, those who had no experience to receive oral health education fell behind in terms of oral health knowledge, awareness, concern and perception of oral health importance, and there was close correlation among their oral health knowledge, awareness, concern and perception of oral health importance. Those without oral health education experience cited lack of opportunities as the reason, the workers preferred to receive education about the prevention and treatment of dental caries, and their favorite educational method was lectures given by dentists, the workers who had oral health education experience had a more intention to receive oral health education than the others who hadn't.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.18-23
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• 2000

The changes of the microorganism composition after therapeutic radiation for oral cancer patients are not well known and the long-term follow-up data are not reported. To obtain basic data for understanding of pathogenesis and prevention and treatment of dental caries and mucositis occuring after radiation therapy, 7 of the oral cancer patients presented at the Seoul National University Oral & Maxillofacial Department between 1997 and 1998 whose treatment plan included radiation therapy were recruited to investigate the changes in bacterial composition(total aerobic count, Candida, Staphylococci, Lactobacilli, S. mutans, and S. salivarius (mitis, sanguis)) of the saliva before, during, and after radiation therapy. The basic data obtained from this study on identification and composition change of the bacteria in saliva of patients treated with radiation therapy can be used (1) as a reference for deciding on the ideal anti-microbial spectrum of the oral rinsing agent to be used in patients treated with radiation therapy for malignant tumor of the head and neck region. (2) to enhance the understanding of increase of opportunistic infection after immunochemical changes of the saliva and its relation to specific bacterial infection. (3) as a reference in prescribing prophylactic antibiotics in immunodepressed patients after radiation therapy.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.357-369
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• 2005

Streptococci are Gram-positive, facultative anaerobes and have no catalase activities. Among mutans streptococci containing ${\alpha}-type$ hemolytic activity, S. mutans is a causative agent for dental caries. As well as acid production yielding the demineralization of tooth enamel, adherence and colonization of S. mutans to the teeth are also important for its virulence. These early colonization are accomplished by the bacterial fibrillar protein, Antigen I/II (Ag I/II) and glucosyltransferase (GTF). Therefore, Ag I/II and GTF are reasonable targets for the development of vaccine against S. mutans GS-5. The ag I/II and gtfD genes from S. mutans GS-5 were cloned and sequenced. Sequence analyses showed the nucleotides sequence of cloned genes had high homology to the sequences previously reported. The sequence alignment of 280 nucleotides between the cloned Ag I/II and the available sequence of the corresponding S. mutans GS-5 showed the perfect match. Comparing with the sequence of gtfD from S. mutans UA159, the corresponding nucleotide sequence of S. mutans GS-5 showed some mismatches and the mismatches introduced changes in four residues out of 105 amino acids, yielding four missense mutations.

• 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.34 no.1
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• pp.53-61
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• 2007

In case of missing tooth caused by dental caries or periodontal disease, it can be restored by various methods, and there has been much interest in implant and tooth transplantation. The success of tooth transplantation is going to be attained through the knowledge of growth, development and calcification of tooth. Tooth transplantation has been experimented in vivo and in vitro. Many animals such as rats, mice, cats and dogs are used for tooth transplantation experiment in vivo. In most experiments, tooth was transplanted into the extraoral site, but rare into the intraoral site In this study, to observe the capacity of formation and mineralization of tooth germ, first molar of a matured white rat was extracted and the cap stage tooth germ of a 13.5 Embryonic day embryo rat was transplanted into the extracted socket. The rats were killed 6 months later and the radiographical and histological results are as followings. 1. Tooth germ transplanted for 2 and 6 months are developing calcified tooth material such as dentin, cementum, pulp tissue, and epithelium around enamel space in the maxilla was seen. 2. The epithelium around enamel space was located beneath the oral epithelium and contained connective tissue and periodontal ligament. 3. Tooth formation was progressed as transplantation period but the size of newly formed tooth was small and the shape of tooth was incomplete.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.535-539
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• 2000

Ectopic eruption of a tooth into the oral environment occurs commonly whereas ectopic eruption of a tooth into other sites is rare. Those that have been reported include the nasal cavity, chin, mandibular condyles, coronoid processes, orbits and maxillary sinus. The etiologic factors of ectopic eruption are developmental disturbances such as cleft palate and teeth displaced by trauma or cysts, maxillary infection, genetic factors, crowding and exceptionally dense bone. In many cases, however, the etiology cannot be identified. Eruption of the teeth into the maxillary sinus is uncommon, however the identification of such teeth can be important since they have the potential to cause considerable morbidity. The definitive treatment is surgical removal of the teeth. A 7 year-old-boy visited the Department of Pediatric Dentistry, College of Dentistry, Yonsei University for treatment of dental caries. The abnormal erupting paths of the left and right maxillary canines were found during routine panoramic radiographic investigations. A panoramic radiograph taken at 13 years old revealed that two maxillary canines were located into the sinus. The teeth were extracted by the Caldwell-Luc approach.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.281-289
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• 2006

Topical fluoride application for children is a widely performed procedure in the field of Pediatric Dentistry for its dental caries prevention effects However, it is recently recognized as having some unwanted effects on several esthetic restorative materials, the author immersed glass ionomer cement, compomer and composite resin specimens in APF gel and measured the surface roughness and also, examined the specimens under the scanning eletron microscope. The followings are the results: 1. In the specimens of glass ionomer cement and compomer, APF gel 4 minute immersion group and pH cycling group show statistically significant increased surface roughness than artificial saliva immersion group (p<0.01). 2. There was no statistically significant surface roughness for composite resin in all group (p>0.05). 3. When the specimens were examined under scanning electron microscope, the surface change were in the order of glass ionomer cement, compomer, composite resin and also in the order of pH cycling group, APF gel 4 minutes immersion group, artificial saliva immersion group.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.660-666
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• 2003

The purpose of this study was to investigate the inhibitory effect of Er:YAG laser against the intraoral acid producing bacterium of S. mutans. Bacterial pellet containing S. mutans KCTC 3065 was irradiated by Er:YAG laser having a $650\;{\mu}m$ diameter beam by non-contact mode. Irradiated parameters were 50mJ, 10Hz and exposure time were 1s, 3s, 5s, 7s, 9s respectively. We obtained the following results of relative growth rate and acid-producing ability of S. mutans by culturing for 48hrs. 1. The growth rate of S. mutans was decreased in the group of laser irradiation compared to the control group(P<0.01). 2. The growth rate at laser irradiation group of 7s, 9s irradiation time was decreased significantly compared to the laser irradiation group of 1s, 3s, 5s irradiation time, until 12 hours(P<0.05). After 24 hours, all groups of laser irradiation were not found to be statistically different in each other. 3. The acid-producing ability of S. mutans was inhibited for a certain duration by irradiation of laser. In summary, the growth rate and acid producing ability of S. mutans decreased according to laser irradiation. This effect was directly related to the amount of irradiation time. These results suggested that Er:YAG laser had an growth inhibition effect on S. mutans.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.228-237
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• 2001

It is well known that glass-ionomer cement and compomer can release fluoride which can inhibit the progression of dental caries. The purposes of this study were to evaluate whether the fluoride from fluoride-containing filling materials can penetrate the dentin bonding adhesive and the dentin bonding adhesive can increase the bond strength of resin-modified glass ionomer. The amount of fluoride release from resin-modified glass ionomer and compomer was measured during 28 days of period and statistically analyzed by t-test. The bond strength of each material with/without dentin bonding adhesive was measured and also statistically analyzed by t-test. The distribution of fluoride from each material into the tooth was explored by electron probe microanalysis system(EPMA). The experimental teeth used were second primary molars about to exfoliate. The amount of fluoride release from each material was diminished by dentin bonding adhesive during 28 days(p<0.05) and the bond strength was not increased by dentin adhesive in resin-modified glass ionomer. The bond strength of group VI was not detectable. The distribution of fluoride from each material into teeth was according to dentino-enamel junction and dispersed into pulp from pulpal floor. The widest distribution was shown in resin-modified glass ionomer cement filled without the application of dentin bonding adhesive.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.437-448
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• 2005

This study is an analysis of distribution of patients who installed Xive implant in Yonsei University Hospital and types of implant site for about 2 years recall check and cumulative survival rate. 41 implant were used in this study. It shows the conclusion below. 1. Patients at the age of 40s and 50s were 60% of all implant cases and average number of implant was 2.4(man), and 1.9(woman). All cases were operated on mandible, 3 implants on anterior region and 38 implants on posterior region. 2. The major cause of tooth loss is dental caries(48.8%), followed by periodontal disease. 3. Most distribution of bone qaulity for mandibular implant site was type II(65.8%) and bone quantity was type B(75.6%). 4. The majority of implants were those of 11, 13mm in length(95%) and regular diameter in width (64%). 5. The 41(19 persons) Xive implants that were placed in the mandibular anterior and posterior region were all survival and showed a 100% 2 year cumulative survival rate. The results provided us with basic data on patient type, implant distribution, bone condition, and survival rate. We wish that our results coupled with other research data helps assist in the further study for better implant success rates, etc.