• Journal of dental hygiene science
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• v.14 no.4
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• pp.448-454
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• 2014

The aim of this study was to evaluate the effect of a water fluoridation program (WFP) on prevention of dental caries in Gimhae City, Korea, with reference to the results of 2012 Korean National Oral Health Survey (KNOHS). In WFP population, 972 subjects including 8-, 10- and 12-year-old children in Gimhae City were examined in 2009. The WFP in Gimhae city has been implemented since 1999. 1872 subjects in non-fluoridated small and medium sized cities similar to Gimhae city were selected from 2012 KNOHS data as the control population. Two dentists who received training in KNOHS with an inter-examiner-agreement examined oral health status of all subjects. To assess the effects of WFP on dental caries, caries preventive fraction was estimated by assessing the differences of decayed, missing, and filled teeth (DMFT) index and decayed, missing, and filled surfaces (DMFS) index, DMFS in pit and fissures and smooth surfaces between WFP population and the control. Univariate analysis of variance adjusted for gender and number of fissure-sealed teeth or surfaces was conducted. DMFT of 12-year-old subjects (n=354) in WFP and control population (n=1,518) were 1.60 and 2.12, respectively, with an estimated prevention effect of 24.7%. Caries preventive fraction on pit and fissure, and smooth surfaces of WFP subjects was estimated 27.5% and 24.0%, among subjects aged 12 years, respectively. WFP in Gimhae City, Korea reduced the prevalence of dental caries and is recommended as a public oral health program where a fluoride-containing toothpastes are commonly used.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.233-238
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• 2005

The study was intended to investigate elementary schoolers' oral health status according to whether the school have and manage an school oral health clinic or not in order to provide useful information for continuously developing the school oral health clinic 1,163 children in Hwasan elementary school in Hwasung city and 485 children in S elementary school in the same locality were selected as the experimental group and the control group, respectively, and orally examined from May 1st to 30th, 2004. The findings from the oral examination were as follows. 1. DMF rate was higher in the higher grades in both the groups. The rate was lower in the experimental group with 45.1% of the children than in the control group with 65.3% of the children. 2. DMFT rate also were higher as the grades were higher in both the groups. The ratio was lower in the experimental group with 30.4% of the children than in the control group with 44.6% of the children. 3. DMFT index was 1.0 in number in the experimental group and 1.6 in the control group. Index increase from the 1st grade to the sixth grade was also more positive in the experimental group. 4. DT rate was a little higher in the experimental group in the first graders, but comparatively decreased to the grades while increased in the control group. In the sixth graders, the rate was 42.4% in the experimental group and 87.7% in the control group, the former was less than the latter by about 50% point. 5. FT rate was a little higher in the control group for the first graders but increased in the experimental group to the grades. The rate in the sixth graders was higher by more than double in the experimental group. Based on the above findings, the region of the study had better oral health statistics than in other regions. The operation of school oral health clinics that provide dental health care to children at the right time seems to contribute to enhancing their dental health status by preventing against dental diseases and changing their relevant knowledge, attitude and behaviors. In the future, more school oral health clinics should gradually be prepared to push ahead with a sustained, extensive dental health project geared toward school-aged children. To make it happen, dental hygienists who are professional medical personnels should be taken advantage of, and in order to beef up the efficiency of preventive measures and oral health education, the best dental health care services should be offered by harnessing dental hygienists and dentists who work at public dental clinics run by local governments.

• Journal of dental hygiene science
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• v.5 no.2
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• pp.89-95
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• 2005

Dental caries is the most prevalent dental issue of childhood. So it is important to control caries form 5 years children and above all, the study of oral health status have been preceding for preventive dental caries. The purpose of this study was to assess the oral health status of 5 years children in seongnam city. The study population consisted of 1035 kindergraten children which had been selected stratified random sampling. The survey is based on WHO, 2000 oral health assessment, which has been modified. From data dt index, ft index, dft index, dt rate, ft rate, percentage of active caries, percentage of pit and fissure sealant, and so on. The findings were as follows: (1) In 5 years children, the experience of dental caries was 73.0% and the percentage with active caries was 49.4%. Dmf index was 4.13 and this observation shows a statistical singnificance. (2) Average number of 5 years children the experience of dental caries surface index was 3.11 and dfts index was 8.91. (3) The experience of dental caries fo the frist molar was 1.9% and the percentage with active caries was 1.1%. Otherwise the percentage of pit and fissure sealant of the first molar was 6.7%. It is show the low percentage for preventive dental caries. (4) Shows percentage of teeth needing treatment for one surface and above two surface was each 27.3%, 34.0%. And percentage of children required single crown and pulp treatment & single crown and tooth extraction was each 3.8%, 4.7%, 3.3%. (5) Soojung-gu and jungwon-gu were having poor oral hygiene as compared to bundang-gu. So it is necessary to establish community oral health program effectively. And for preventive dental caries and early diagnosis and early treatment consider with community characteristic.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.489-501
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• 1997

Electropolymerization of 2-vinylnaphthalene (2-VN) and methylmethacrylate (MMA) with high radiation resistance property was conducted on the surfaces of carbon fibers by using a nonaqueous solution of comonomers dissolved in N,N-dimethylformamide containing sodium nitrate as a supporting electrolyte. The fabrication of carbon fiber/2-VN/MMA prepreg was performed electrochemically in 1:1 comonomer solution. Electropolymerization was conduced by changing the current density, initial comonomer concentration, and reaction time. The weight gain on the surface of the carbon fibers was measured by thermogravimetric analyser (TGA). The highest weight gain of 50 wt% was obtained at 600mA/g~800mA/g current density range, but the weight gain was rapidly decreased above 800mA/g current density. The weight gain was increased with the concentration of comonomer, while the concentration of electrolyte had almost no effect on the weight gain. At 300mA/g current density, weight gain rate was increased abruptly to the initial 30 minutes of reaction time. After that the rate was decreased due to the generation of gas bubbles. In order to check the effect of coated polymers on the radiation resistance, morphology changes before and after $\gamma$-ray irradiation was investigated for the composites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.499-505
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• 2013

Cr(VI)-4-(dimethylamino)pyridine[4-(dimethylamino)pyridinium chlorochromate] was synthesized by the reaction of 4-(dimethylamino)pyridine with chromium trioxide in 6M-HCl, and characterized by IR, ICP. The oxidation of benzyl alcohol using 4-(dimethylamino)pyridinium chlorochromate in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order: cyclohexene$H_2SO_4$ solution), 4-(dimethylamino)pyridinium chlorochromate oxidized benzyl alcohol and its derivatives(p-$OCH_3$, m-$CH_3$, H, m-$OCH_3$, m-Cl, m-$NO_2$) smoothly in DMF. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.68(303K). The observed experimental data was used to rationalize the hydride ion transfer in the rate-determining step.

• The Journal of Korean Society for School & Community Health Education
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• v.10 no.1
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• pp.87-104
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• 2009

Objective: In this study, the dental health care knowledge, dental health behaviors and dental health status of elementary school students were compared and analyzed in the cases of their schools having dental health care center or not one. Methods: The target groups were 167 students of A school (experimental group) where pit-and-fissure sealants, fluoride mouthrinsing, and fluoride gel application were carried out with all grades of students by school dental health care center and 158 students of B school (control group) where fluoride mouthrinsing, for all grades students and pit-and-fissure sealants for the first grade students are carried out but have no the school dental health care center. Results: This study was carried out through the answer sheets and recordings of dental inspection. The findings of this study are as follows: 1. The dental health care knowledge was compared and the results showed that on average 14.2$\pm$2.1 in experimental group and 14.0$\pm$1.9 in the control group were no significantly different (p>0.05). 2. The dental health behaviors were compared and the results showed that the experimental group was significantly different(p<0.05) in terms of the number of times of dental brushing a day, the method of tooth brushing, the time of tooth brushing, the experience of tooth brushing with fluorine, the kinds of snacks and tooth brushing in school after lunch. But there was no significant difference(p>0.05) in the time of tooth brushing and the tooth brushing after eating snacks. 3. The DMF rate was compared and the results showed the significantly difference between the average experimental group and 53.8$\pm$5.0 in the control group(p<0.05). 4. The DMFT index was compared and the results showed the significantly difference between the average 0.6$\pm$2 in the experimental group and 1.4$\pm$1.6 in the control group(p<0.05). 5. The DMFI rate was compared and the results showed the significantly difference between the average 4.2$\pm$8.3 in the experimental group and 9.5$\pm$11.0 in the control group. (p<0.05). 6. The DT rate were compared and the results showed the significantly difference between the average 10.2$\pm$29.5 in the experimental group and 32.4$\pm$44.0 in the control group(p<0.05). 7. The FT rate were compared and the results showed the significantly difference between the average 88.5$\pm$31.0 in the experimental group and 67.5$\pm$44.0 in the control group(p<0.05). Conclusions: Based on the results, above there was no significant difference in dental health care knowledge between both the experimental and the control group. But we discovered that the experimental group is better than the other one in dental health care behaviors and dental health status. Therefore, we could conclude that the school dental health care center efficiently carried out the dental care and treatment. As school dental health care centers did not work out efficiently in terms of their educating on the dental health acre knowledge, the related programs to be developed and supported.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.571-577
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• 2009

This research basically work on oral health condition of the diabetes patients with data from 2006 National oral Health Survey. Based on this data, this research will provide basic materials about developing program with necessity of Recognition and education of the oral health condition. Analysis with using SPSSWIN 12.0 makes some results on the below. First, Existence and nonexistence based on age division shows result that over 70 years old gets 39.8%, which is highest percentage(p<0.05). Second, In existence and nonexistence based on sex distinction and age division, Women gets higher percentage (60.8%) than percentage of the men (39.2%). Third. Both diabetes patient and control group answered 'unhealthy' about subjective recognition of the oral health condition. Forth, percentage of caries on permanent tooth 12 92.0% for diabetes patient (p<0.05). Fifth, Answer about periodontal structure of diabetes patient is 88.9% of blooding periodontal structure(p<0.05). Sixth, Result of the demand of caries and periodontal structure treatment from diabetes patients show that diabetes patient does not feel necessity about treatment although they gets hardship of chewing. Also, it does not show any statistical difference. Seventh, Results of the oral health practice based on demographic characteristics are eating snack(highest answer). Latest visiting dental hospital before 1 year ago, or long before this. Frequencies of brushing tooth are less than 3 times. Also, il does not show any statistical difference.

• Membrane Journal
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• v.6 no.3
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• pp.157-165
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• 1996

Polysulfone(PS) membranes were prepared from homogeneous PS solutions by the phase inversion technique. When propionic acid(PA) was added into a casting solution of n-methylpyrrolidone(NMP) and PS, precipitation rate of the solution film was accelerated. This kind of acceleration was consistent, even though a precipitating nonsolvent was changed from water to isopropanol. These phenomena were caused by decrease of nonsolvent tolerance in the casting solution due to addition of PA. PS powder was prepared by precipitation of a 3wt% solution in dimethylformamide(DMF) using ethanol as nonsolvent. Gas adsorption analysis of the powder showed that the capillary condensation sites were found in the powder structure. Membranes prepared from PS solution(15wt%) in NMP had the following characteristics of gas adsorption and water permeation. In gas adsorption analysis, the membrane precipitated using isopropanol showed low uptake of nitrogen gas and the capillary condensation sites were not found. On the contrary, a significant amount of the capillary condensation sites was found in the membrane coagulated by water, which was related to increase of nitrogen uptake. tn the membrane prepared froin the solution including PA, an increase of the Henry's law sites and the Langmuir sites was not found clearly. However, the capillary condensation sites were significantly increased, and the water transport also increased.