• Journal of Korean society of Dental Hygiene
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• v.14 no.3
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• pp.391-398
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• 2014

Objectives : The purpose of the study is to investigate the oral health knowledge and behavior in teachers with or without the school dental clinic. Methods : The subjects were 133 teachers with or without the school dental clinic in Gunsan. A self-reported questionnaire was filled out by the teachers from September 9 to November 2, 2013. The data were analyzed by SPSS version 21.0. Results : The groups were divided into two. Experimental group was school dental clinic operation group and the control group was no operation group. The experiment group showed the high score of recognition of fluoridation and sealant(p<0.01). The control group showed the high score of recognition of sealant(p<0.01). Conclusions : Continuous operation of the school dental clinic is essential to promote the lifelong oral health care in the elementary school children and the teachers. So the nationwide expansion of the continuous school dental clinic is very important to prevent the dental caries in the elementary school children.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.128-131
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• 2013

Energy losses through windows and doors are big problems in the construction industry. For glass only, it has takes the largest portion of mass from window assembly and it responsible for 24 ~ 45% of energy loss from total building energy loss. Insulating glass unit should maintain their basic functions during their working life in order to contribute positively for global warming issue. There have been many research works for improving insulating glass unit durability. But it is not easy job to fulfill the requirements because insulating glass units composed of many components. So, overall it is required to have right qualify control procedures starting from material selection to fabrication, shipping and installation to the customer site. In this report, we have reviewed the durability of insulating glass unit made from different grades of sealing materials based on globally accepted industry codes such as EN1279. ASTM E 2190 and Locally available code. KS L 2003. The result showed that there is a relationship between the mechanical properties of insulating glass 2nd sealant and the durability of the units.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.204-212
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• 2008

The purpose of this study was to compare the apical microleakage in root canal filled with Resilon by methacrylate-based root canal sealer or 2 different self-adhesive resin cements. Seventy single-rooted extracted human teeth were sectioned at the CEJ perpendicular to the long axis of the roots with diamond disk. Canal preparation was performed with crown-down technique using Profile NiTi rotary instruments and GG drill. Each canal was prepared to ISO size 40, .04 taper and 1 mm short from the apex. The prepared roots were randomly divided into 4 experimental groups of 15 roots each and 5 roots each for positive and negative control group. The root canals were filled by lateral condensation as follows. Group 1: Gutta-percha with AH-26, Group 2: Resilon with RealSeal primer & sealer, Group 3: Resilon with Rely-X Unicem, Group 4: Resilon with BisCem. After stored in $37^{\circ}C$, 100% humidity chamber for 7 days, the roots were coated with 2 layers of nail varnish except apical 3 mm. The roots were then immersed in 1% methylene blue dye for 7 days. Apical microleakage was measured by a maximum length of linear dye penetration after roots were separated longitudinally. One way ANOVA and Scheffe's post-hoc test were performed for statistical analysis. Group 1 showed the least apical leakage and there was no statistical significance between Group 2, 3, 4. According to the results, the self adhesive resin cement is possible to use as sealer instead of primer & sealant when root canal filled by Resilon.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.204-212
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• 2008

The purpose of this study was to compare the apical microleakage in root canal filled with Resilon by methacrylate-based root canal sealer or 2 different self-adhesive resin cements. Seventy single-rooted extracted human teeth were sectioned at the CEJ perpendicular to the long axis of the roots with diamond disk. Canal preparation was performed with crown-down technique using Profile NiTi rotary instruments and GG drill. Each canal was prepared to ISO size 40, .04 taper and 1 mm short from the apex. The prepared roots were randomly divided into 4 experimental groups of 15 roots each and 5 roots each for positive and negative control group. The root canals were filled by lateral condensation as follows. Group 1: Guttapercha with AH-26, Group 2: Resilon with RealSeal primer & sealer, Group 3: Resilon with Rely-X Unicem, Group 4: Resilon with BisCem. After stored in $37{\circ}C$, 100% humidity chamber for 7 days, the roots were coated with 2 layers of nail varnish except apical 3 mm. The roots were then immersed in 1% methylene blue dye for 7 days. Apical microleakage was measured by a maximum length of linear dye penetration after roots were separated longitudinally. One way ANOVA and Scheffe's post-hoc test were performed for statistical analysis. Group 1 showed the least apical leakage and there was no statistical significance between Group 2, 3, 4. According to the results, the self adhesive resin cement is possible to use as sealer instead of primer & sealant when root canal filled by Resilon.

• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.473-478
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• 2004

This study focused on the charateristic of magnetic fluids, the viscosity deviation of magnetic fluids due to temperature changes, and fabrication of a 'purely' liquid type microvalve. The viscosity of magnetic fluids decreases sharply during increasing of temperature. The viscosity of magnetic fluids is rated 1,000 cP at the room temperature and 25 cP when the temperature reaches $100^{\circ}C$. Briefly, it is remarkable that the fluid flow can be controlled by the temperature and this characteristic can be adopted to the microfluidics as a microvalve. The fabrication of a liquid type microvalve is more easy than solid state microvalves and which can increase an efficiency of the controlability with respect to the thermo-pneumatic micropump which is studied broadly for many years. When the magnetic fluid used as a sealant for high level sealing, the pressure leakage is less than solid state microvalve. The experimental results show that the pressure drop in microchannel, filled with the magnetic fluid, is significant in the temperature range of $20^{\circ}C{\sim}50^{\circ}C$ and this result explains why the use of magnetic fluids is possible as a microvalve searcher uses this characteristics. Well known thermo-pnumatic.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.504-511
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• 2001

Preventive resin restoration, extended concept of occlusal pit and fissure sealing, is procedure composed of as follows. Cavity preparation is limited to areas of initial caries The cavity is then restored with composite resin, while other sound pits and fissures are sealed with pit and fissure sealant. If pit and assure sealant with which microrestoration is possible is used, it may be of great benefit to both patient and operator in case of difficult-to-control children s treatment. However study on preventive resin restoration using this kind of materials have been scarce. The purpose of this study was to compare the microleakage of four different modes of preventive resin restoration. Restoration using only composite resin was compared together Fifty-five bicuspids were prepared with small class I cavity preparation on the occlusal surface, divided into the following groups and restored accordingly. Group 1 : Cavity was restored with Z-100 composite resin Group 2 : Cavity was restored with Z-100 composite resin. Pits and fissures were then sealed with Teethmate F-1 Group 3 : Cavity was restored with Z-100 composite resin Pits and fissures were then sealed with Ultraseal XT-plus Group 4 : Cavity and pits and fissures were restored with Ultraseal XT-plus altogrether Group 5 : Cavity was restored with Ultraseal XT-plus. Pits and fissures were then sealed with the same material. After restoration, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue solution for 24 hours, then rinsed with tap water. The teeth were then embedded in resin and cut buccolingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage. The results were as follows : 1. Group 4 showed the greatest microleakage, while group 3, showed the least. The mean microleakage decreased in the following order:4>1>5>2>3. 2. There was no stastically significant difference between group 1 and group 5(p>0.05). However, group 1 showed significantly greater microleakage compared to group 2 and 3(p<0.05) Group 1 showed significantly less microleakage compared to group 4(p<0.05). 3. Group 2 showed no statistically significant difference compared to group 3(p>0.05). However group 2 showed significantly less microleakage compared to group 4 and 5(p<0.05) 4. Group 3 showed significantly less microleakage compared to group 4 and 5(p<0.05). 5. Group 5 showed significantly less microleakage than group 4(p<0.05).

• The Korean Journal of Health Service Management
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• v.4 no.2
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• pp.63-72
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• 2010

The present study purposed to prevent oral diseases and to improve oral health in children. For this purpose, we selected 70 cases who are 5~7 years old preschoolers at the kindergarten affiliated to G College in Gyeongsangbukdo, and analyzed the general patterns of oral care and the relation of the patterns with dental plaque and deciduous dental caries in the children. Specifically, we conducted oral examination and applied pit and fissure sealant according to the eruption of deciduous molar and first molar. In addition, we executed the 1st and 2nd tooth brushing instruction (TBI), and surveyed S-OHI and PHP twice. Excluding 14 preschoolers who did not appear in the 2nd survey, we performed the study with 56 preschoolers and drew conclusions as follows. 1. The number of decayed or missed or filled teeth among deciduous teeth was 3 or more in 42.9% of female children, and 46.4% of male children, so male children showed a slightly higher rate. 2. The degree of dental plaque formation was $1.64{\pm}1.22$ among the surveyed children. 3. The oral health index was lower after TBI than before in all the children (P<.001). 4. Change in the oral health index was particularly larger in 7 year old female children (p<.005). 5. The patient hygiene performance index was lower after TBI than before in both the buccal surface and lingual surface of the children (p<.005). 6. The patient hygiene performance index was lower after TBI than before in all of male children's teeth except the right maxillary first deciduous molar (p<.001).

• Journal of Korean society of Dental Hygiene
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• v.15 no.2
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• pp.253-259
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• 2015

Objectives: The purpose of this study was to investigate the oral health behavior according to oral health education experience in the elementary school teachers and to provide the basic data for the development of oral health education program. Methods: A self-reported questionnaire was filled out by 239 elementary school teachers in Busan and Ulsan from May 7 to 31, 2013. The questionnaire consisted of general characteristics of the subjects, use of oral health devices, dental clinic visit within a year, purpose of dental clinic visit, subjective oral health condition, place and contents of oral health education, future contents of oral health education, purpose of tooth brushing, recognition of sealant, recognition of dental caries prevention effect of fluoride, and method and frequency of tooth brushing. Data were analyzed by Predictive Analysis Software(PASW) Statistics $19.0^{(R)}$(SPSS Inc., Chicago IL, USA). Results: Of the 239 teachers, 187 teachers had oral health education experience and 52 did not. Those who had oral health education experience reported higher scores in tooth brushing than those who did not. 59.4% of the respondents answered the experience of oral health education in dental clinics. Conclusions: Oral health behavior was different from the experience of oral health education in the elementary school teachers. The teachers are the most important persons influencing on the right tooth brushing habit in the students. So the teachers must take the continuing and systematic oral health education.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.613-619
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• 2001

The aims of this study were to compare the accuracy, sensitivity and specificity of cnventional visual examination, radiography and a new laser fluorescence method, KaVo Diagnodent, for the detection of occlusal caries lesions. One hundred sound human premolars and molars which had no restorations or interproximal cavities were tested by three methods. Tooth lesions depth was assessed at histologic examination using Caries detector dye The following results were obtained. 1. Diagnodent show 7.8 in sound tooth, 25.4 in initial caries, 30.5 in enamel caries, and 53.8 in dentin caries with average score 2. Spearman and Pearson relation coefficient was high between tooth-specimen test with dye and Diagnodent(0.736, 0.619), visual examination(0.664, 0.666), and was low between tooth-specimen test with dye and radiographic examination(P<0.01, total) 3. Accuracy of occlusal caries was highest on Diagnodent(65%) and lowest on radiographic examination(35%) 4. In initial caries, the sensitivity and specificity of Diagnodent method was the highest. In enamel caries, the sensitivity of visual examination was the highest and specificity of Diagnodent method was the highest. In dentinal caries, the sensitivity and specificity of Diagnodent method was the highest and sensitivity of visual examination was the lowest.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1483-1491
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• 2010

The purpose of this study was to examine current status of the types of dental filling materials and preventive materials among Korean children in mixed dentition. Seven elementary schools were randomly selected from four metropolitan regions in South Korea. The total of 711 children aged 9-10 years old were examined with their parents’ informed consents. Oral examination was conducted by one trained dentist. The mean number of dfs was $7.9{\pm}8.0$ ($ds=1.3{\pm}2.5,\;fs=6.6{\pm}7.6$) and DMFS was $1.4{\pm}2.2$ ($DS=0.2{\pm}0.8,\;FS=1.1{\pm}2.1$). The average of filled surfaces using amalgam, composites, sealants, and others were $2.8{\pm}3.9,\;1.6{\pm}2.8,\;2.9{\pm}3.2$, and $4.5{\pm}7.0$, respectively. The use of dental filling material according to region, the amalgam was the highest in Daegu and the resin was the highest in Pusan. In permanent teeth, about 70% of total filling surfaces had sealant and about 20% was resin fillings, and the proportion of amalgam filling surfaces was less than 10%.