• The korean journal of orthodontics
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• v.31 no.6 s.89
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• pp.567-578
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• 2001

To investigate the difference of Texture exhibited on interproximal enamel surface with each different stripping method and the susceptibility of proximal enamel to demineralization after stripping and the application of a topical fluoride go] and sealant, one hundred human premolars, which were Previously extracted for orthodontic reasons were evaluated by means of Scanning electron microscopy and laser fluorescence. The results were as follows : 1. No matter what the initial stripping instrument was the furrows that resulted from all the stripping methods were not completely removed by careful polishing. 2. Among the enamel surfaces that were treated with three different initial abrasive instruments, followed by the same polishing method (Sof-$Lex^{(r)}$ disks), the enamel surfaces that were treated with 700 crosscut carbide bur showed the smoothest surfaces. 3. The stripped teeth, no matter what the initial stripping instrument was, were less resistant to initial demineralization than untreated teeth. But no difference in caries susceptibility according to differently stripped methods was found (p<(0.001). 4. Teeth treated with APF-gel or sealant were mote resistant to demineralization than those treated without other treatment after stripping (p<0.001). 5. Comparing groups treated with APF-gel to groups treated with sealant, the former was more resistant to demineralization than the tatter (p<0.05). In conclusion, enamel surfaces that were stripped jnterproximally were less resistant to demineralization even though various attempts were made to produce smooth, self-cleaning enamel surfaces. Therefore, additional treatment-sealant or calcifying/ fluoridating solution To the stripped enamel surfaces is recommended.

• Journal of Korean society of Dental Hygiene
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• v.3 no.1
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• pp.13-24
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• 2003

The researcher worked with a total of 158 high school girls visiting the scaling practice room at the department of dental hygiene in Jinju Health college from November 11, 2002 to December 4, 2002, having their teeth scaled, observing their teeth and interviewing them with the aid of questionnaires. The findings can be summarized as follows. 1. The survey on the understanding of dental health and the attitudes of the subjects shows the following results : "I have never learned how to brush teeth" (65.8%: 104 girls); "I brush my teeth twice a day" (57.0%: 90 girls) : "I brush my teeth for 2 minutes"(44.3%: 70 girls): "I brush my teeth vertically and horizontally" (53.2%: 84 girls): "( brush my teeth, gum and tongue" (462%: 73 girls): "I use one brush for two months" (40.5%: 64 girls); "I don't have any floss" (582%: 92 girls): "I have never had my teeth scaled" (84.2%: 133girls) : "Smoking is bad for the teeth" (77.8%: 123 girls): "Drinking is bad for the teeth" (48.7%: 77 girls): "I have ever visited dental clinics" (92.4%: 146 girls). 2. The study on part of the teeth most exposed to caries shows the following results : Mandibular right first molar(79.8%: 126 girls): Mandibular left first molar(77.5%: 124 girls), Mandibular left second molar(70.2%: 111 girls). Mandibular right second molar(65.7%: 104 girls). Maxillary left first molar(59.5%: 94 girls): Maxillary left second molar(59.5%: 94 girls): Maxillary right first molar(58.2%: 92 girls). Maxillary right second molar(50.7%: 80 girls) 3. The statistics on the subjects' caries show the following results: DMF rate: 943%: DMFT rate: 25.61%: DMFT index: 7.17 teeth : DT rate: 4651%: FT rate: 52.25%: MT rate: 124% 4. The survey on dental caries statistics, dental health, dental health behavior, and the subjects' attitudes shows the following results: The worse the subjects' dental health was(r=-327, p<.001), the more they visited dental clinics(r=.195, p<.05), the higher DMT rate, DMFT index were; The more the subjects visited dental clinics(r =.359, p<.001), the higher DT rate was; The worse the subjects teeth went(r=-.197, p<.05), the higher MT rate was. It is necessary that systematic and substantial dental health education for high school students should be carried out in regard to plaque control, fluoride application, diet control, pit & fissure sealant as a part of developing national health policies designed for the dental health of the teenagers.

• Journal of Korean society of Dental Hygiene
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• v.1 no.2
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• pp.201-211
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• 2001

Dental caries causes the majority of tooth loss among Koreans. Korea is experiencing an increase in dental caries. And it shows a high prevalence of caries in preschool children, which contrasted with the much-improved situation in developed countries. So, it is important to control caries from preschool periods in Korea. Recently, inspections of the teeth of preschool children for evidence of dental disease became a legislative duty in Korea following Oral Health Act(2000). But, standardized oral health programs in preschool children is not yet proposed. Therefore, it is necessary to develop an community based oral health program in preschool children. The purpose of this study was to obtain basic data for the development of community based oral health program in preschool children of Sungnam city. Oral health status in primary dentition were surveyed in 862 2-6 year-old preschool children of Sungnam city by WHO criteria. From the data, df rate, percentage of preschool child ren with active caries, dft index, dt rate, percentage of preschool children with pit and fissure sealant of each age were calculated, and discussed. The obtained results were as follows : 1. The experience of dental caries in primary dentition showed a tendency to increase quickly between 2 and 3 year old children. So, the oral health program in preschool children should be developed to prevent dental caries and control their oral health under three years of age. 2. In 5 year-old children, the percentage with active caries was 60.8% and dft index was 5.06. The dt rate showed a tendency to decrease as proportion to age, but even though 6 year-old children, the dt rate was 47.7%. Therefore, the annual screening dental examination and oral health education programs at the institution for preschool children should be developed to detect and treat dental caries in primary dentition at early stage. 3. The percentage of preschool children with pit and fissure sealant at six years of age was 10.2%. So, pit and fissure sealant and professional fluoride application programs in Public Health Center should be developed to prevent dental caries. 4. Also, it is necessary to establish oral health goals in preschool children and develop water fluoridation program 10 improve and preserve oral health of preschool children in Seongnam city, effectively.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.59-68
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• 2011

Objectives : To investigate the knowledge and recognition level of fluorine by teaching career among class teachers, who are primarily responsible for oral health education, despite lack of expertise in oral health, by playing a model role for students through continuous contacts with them, and provide basic elementary data about accurate knowledge and how to correctly use fluorine remarkably effective in preventing dental caries. Methods : A self-administered survey was conducted with 539 teachers at 21 elementary schools in Jinhae City from September 1 to October 15, 2010, drawing the following conclusions. Results : 1. As for the channel for acquiring knowledge of oral health, the highest frequency was found in health programs for respondents with less than 9 years of career, in dental clinics for those with 20 to 29 years of career, and in PR booklets for those with 10 to 19 years and 30 years and longer of career. 2. Use of fluorine-containing toothpaste and fluorine spread is very effective and effective in preventing dental caries got 64.9%, 72.2%, 72.3%, 77.7% and 54.0%, 63.1%, 62.2%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 3. Intake of fluoride and toothbrushing with fluoric solution is very effective and effective in preventing dental caries got 33.3%, 40.1%, 39.5%, 55.3% and 50.0%, 54.9%, 48.8%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 4. Use of fluoric tablets is very effective and effective in preventing dental caries got 32.9%, 36.0%, 36.1%, 47.3%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 5. Most of the elementary school teachers knew the fact that fluorine increases dental resistance to cavity and prevents bacterial growth but gave incorrect responses to properties of becoming basic nutrients or inducing recalcification. Conclusions : Various types of application of fluorine during the elementary-level childhood experiencing the most frequent dental caries will be very useful in improving oral health in the future. It is necessary to enable class teachers to get correct recognition of fluorine through supplementary and job training based on technical knowledge and various educational materials so that they, who are directly responsible for health management through continuous contacts with students, can understand how to correctly use fluorine and get accurate knowledge.

• Membrane Journal
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• v.14 no.2
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• pp.108-116
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• 2004

In this study, the pore-filled ion-exchange membranes were prepared by using the asymmetric PVDF membrane as a nascent membrane. First, the solution of PVBCI having the chlorornethylate aryl ring of 80 percents and DABCO was made with the mixed solvent of THF and DU (8:2). These mixed solution was then, filled in the pores of PVDF membrane, and left for a day to complete the gelation. Finally the pore-filled anion-exchange membrane is obtained fallowed by the amination of the remaining chloromethyl groups with trimethylamine (TMA, 40 wt% in water) forming the positive ammonium ion sites. This 2 step procedure enabled us to produce the pore-filled membranes without change of size, and to control the properties of final membrane with various degree of cross-linking. The results of SEM and AFM showed the polyelectrolyte existed in the pores of nascent membrane as a certain configuration. From the investigation of the solvent affecting much to the permeability and rejection, it was found that the membranes using mixed solvent of THE and DMF (8:2) showed better performances than the membranes produced by THF only. The result of an investigation for the water permeability of the final membrane at low pressure (100 Kpa) showed a typical ultrafiltration membrane's permeability (8 ∼ 10 kg/$m^2$hr) and good values of rejection (55∼60 percent).

• Journal of dental hygiene science
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• v.14 no.4
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• pp.488-494
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• 2014

The purpose of this study is to analyze the association of oral health of the elderly and oral health quality of life. The subjects of this study were 282 participants who received the fluoride application and the scaling service through program targeting elderly people carried out by a public health center located in Gyeongsangbuk-do Province. Data were collected from January 2011 to December 2011. The result of comparing subscale scores of quality of life related to oral health depending on socioeconomic characteristics showed that functional limitation scores were lower as educational level got higher. The result of comparing subscale scores of quality of life related to oral health depending on status of oral health and frequency of tooth brushing showed that quality in functional limitations, physical pain, psychological discomfort, physical disability, psychological disability, social disability and handicap scores were lower as the number of cavities got more. The result of multiple regression analysis to identify the factors affecting the quality of life related to oral health showed that the number of cavities and installation of denture were significant variables. The results of this study showed that there was significant association of oral health status and oral health related quality of life of the elderly. In order to maintain the oral health related quality of life, it is important to keep many number of residual teeth even if a person gets older and to support the installation of dentures if necessary.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.19-29
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• 2002

The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1127-1137
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• 2000

Applications of lanthanum ion and crude rare earth chloride to the phosphate wastewater and fluorine wastewater, respectively, as treatment agents were studied. For the investigation of phosphate removal characteristics according to the amount of lanthanum ion, initial phosphate content was decreased by about 50% when molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] was 0.25 and nearly all of phosphate was removed when the molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] to be doubled. The removal of phosphate by $La^{3+}$ appeared to reach equilibrium state rapidly, and it was exothermic reaction since the removed amount of phosphate was diminished somewhat when the reaction temperature was increased. The zeta potential of combined particulate compound of lanthanum ion and phosphate was located for its isoelectric point at pH 5.5 and the turbidity of treated wastewater was found to vary according to the pH in a similar manner as the absolute value of zeta potential of the combined particulate compound did. For the treatment of fluorine wastewater by crude rare earth chloride, the remaining fluorine content after treatment decreased as the dosage of crude rare earth chloride increased. Whereas, the turbidity of treated wastewater and the amount of sludge generated were shown to increase as more crude rare earth chloride was added. The remaining fluorine content and the turbidity of treated wastewater were decreased and the amount of sludge generated was observed to increase according the increase of coagulant dosage under the condition of constant input of crude rare earth chloride.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.290-298
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• 2021

A purification process was performed for the application of natural graphite as an anode material. The influence of the structural change and impurity content of graphite according to the process on the anode electrochemical characteristics was investigated. Natural graphite was chemically/physically purified by acid-treatment which used different amounts of solution of ammonium fluoride/sulfuric acid in the same ratio and thermal treatment used different temperatures (800~2500 ℃). Acid-treatment had limitation to remove impurities, and identified that all impurity contents was removed except some traces of atom such as Si by after progressed thermal-treatment until 2500 ℃. The anode materials characteristic of graphite treated by purification process was improved, and changes in the structure and impurity contents affected dominantly the capacity, rate property and initial Coulombic efficiency. Consequently, the complex purification process improved the graphite structure and also the performance of lithium ion battery by controlling the excessive formation of solid electrolyte interphase and expanding Li⁺ insertion space originated from the effective removal of impurities.

• Journal of Korean Dental Hygiene Science
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• v.1 no.1
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• pp.11-21
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• 2018

This research is intended to develop oral health education program that can improve quality of oral health of infants by investigating the actual condition of oral health education provided to students major in early childhood education and contents and method of oral health education that they needed. A questionnaire survey was conducted for 427 students enrolled in related departments such as the Early Childhood Education Division and the Early Childhood Education Department at five universities in Gyeongsangnam-do. Questionnaires consisted of general characteristics, awareness of oral health, presence of experience in oral health education, necessity of oral health education, preference for oral health education method, oral health education contents. The collected data were analyzed by SPSS(Statistical Package for the Social Science) Ver 20.0. 1. Presence of experience in oral health education based on the general characteristics showed statistically significant differences only concerning the 'school system' and the 'school year' (p<0.05), and subjective awareness of oral health based on the presence of oral health education experiences showed statistically significant differences concerning the 'interest in oral health' and the 'importance of oral health' (p<0.05). 2. Necessity of oral health education based on the subjective awareness of oral health showed statistically significant differences concerning the 'interest in oral health' and the 'importance of oral health' (p<0.05). 3. Necessity of oral health education based on the preference for oral health education method showed statistically significant differences concerning the 'intention to participate in oral health education' and the 'oral health education cycle' (p<0.05). 4. The most necessary information for oral health education is proper toothbrushing method 4.24, cause of tooth decay and prevention method 4.13, helpful food and poor food for tooth 3.97, toothbrush selection and storage method 3.85. Fluoride application and fissure sealant were lowest 3.38. As a result of this research, necessity of oral health education was large regardless of general characteristics, experience in oral health education, subjective awareness of oral health, and preference for oral health education. Also the more the 'interest in oral health' in 'subjective awareness of oral health', the more the 'necessity of oral health education' and 'intention to participate in oral health education'. Therefore it is necessary to develop systematic and repetitive oral health education for students major in early childhood education.