• Journal of computational fluids engineering
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• v.17 no.2
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• pp.58-64
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• 2012

Turbulent flows in a intake part of vacuum cleaner are studied by RANS simulations. The governing equations are solved by the SIMPLE algorithm based on the finite volume method of the unstructured grid system. The predicted results show that the suction performance is closely related to the variation of flow structure in the intake part. In order to investigate for the cleaning of bedclothes and carpet without sticking, several design changes are applied. The introduction of a solid cylinder in the intake part changes vortical structures significantly. Based on this result, a new design with spiral brushes is proposed. The design shows a good behavior for the suction performance and the flow control.

• Journal of Korean society of Dental Hygiene
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• v.14 no.6
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• pp.887-894
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• 2014

Objectives: The purpose of this study was to investigate the oral health education and oral health care in the implant wearers. Methods: A self-administered questionnaire was conducted by 253 patients in 14 different dental hospitals and clinics in Seoul and Gyeonggi-do from July 1 to September 30, 2012. The instrument was adapted from Kang and Lee, Yu and Shim, and Ko and Jang on the basis of the previous study. The questionnaire consisted of 12 questions including general characteristics of the subjects(4 questions), oral health education(3 questions), behavior and attitude of tooth brushing(3 questions), and use of auxiliary supplies(2 questions). Results: 1. 38.3% of the patients received the dental care education for the first time. The most common education method was demonstration by dental hygienists(28.9%). 26.2% of the patients wanted to know the right toothbrushing method. 2. The best toothbrushing methods were rolling method(28.9%) and Leonard's method(28.9%). 19.4% of the patients changed the toothbrushing method after education. 22.5 percent brushed their natural teeth and implant teeth by a different maneuver. 3. The interdental brush was the most commonly used product(35.8%) and most of the patients the interdental brush once a day(36.6%). 4. There was a significant difference between the frequency of toothbrushing and method(p<0.05). 5. There was a significant difference between the separate brushing of implant and natural teeth by the frequency of toothbrushing and method of education(p<0.05). 6. Use of interdental brush had an influenced on education method(p<0.05). Conclusions: Regular dental checkup and use of interdental brush can improve the oral care for the implant wearers. Regular use of interdental brush can prolong the life span of implant tooth and keep the patients' teeth in good condition.

• Journal of dental hygiene science
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• v.17 no.3
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• pp.267-274
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• 2017

This study aimed to compare the effectiveness of chewable toothbrush and manual toothbrush and provide basic data for recommendation of the chewable toothbrush in specific groups and situations. A total of 20 subjects participated in this study (rolling method, 10; non-rolling method, 10). After professional prophylaxis, participants used the manual toothbrush to brush their teeth for 3 minutes. After a 7-day wash-out period, participants used the chewable toothbrush according to the manufacturer's instructions. Pre- and post-plaque indexing of the teeth was performed. The dental plaque index was assessed using the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) for amount of plaque and Silness-Loe Plaque Index (SLPI) for plaque thickness. The difference between pre- and post-dental plaque index was analyzed using a paired t-test and the Wilcoxon signed-rank test. The Mann-Whitney U test was also used to compare the dental plaque index reduction rates. The dental plaque index differed significantly between the chewable toothbrush and the manual toothbrush. The TMQHPI reduction rate was significantly different between the rolling and non-rolling method groups for the manual toothbrush but not the chewable toothbrush. The difference in SLPI reduction rate between the rolling and non-rolling method groups was significant for the manual toothbrush but not for the chewable toothbrush. Differences in the dental plaque index reduction rates between the chewable and manual toothbrushes were not significant in the non-rolling method group. The results of this study showed higher reduction rates in dental plaque with manual toothbrush use than with chewable toothbrush use. However, the non-rolling method group did not show statistically significant differences according to toothbrush type. The present study showed that a chewable toothbrush can be an alternative to a manual toothbrush for individuals who have difficulty using the generally recommended rolling method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1049-1052
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• 1997

The pupose of this study on the surface finishing is to examine the performance of brushing as a means of reducing the surface roughness of the precision theaded shafts in ball screw assemblies. Ball screws provide superior performance compared to other types of screw feeds in terms of static and dynamic rolling resistance,backlash,and wear characteristics. The Reduction of the surface roughness of the lead shaft in ball screw assembiles is essential for precision movement,high speed/low noise tracel, and for low wear/long life. To reduce machine dependent errors that would influence the surface roughness compared with other lapping or polishing techniques,experiments will be performed using special wire brushes to polish precision ground shafts. The best results were obtained using the Al /sab 2/O /sab3/ brushes, with the Al /sab 2/O /sab3/ #500 grit brush producing a surface finish of approximately 0.7 .mu.m, and the Al /sab 2/O /sab3/ #600 grit producing a surface finish of approximately 0.8 .mu.m. Both of these results were produced at the highest wheel polishing speed of 3520 rpm. The SiC #500 brush produced a surface roughness of approximately 1 .mu.m at 3520 rpm.

• Journal of the Korean Society of School Health
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• v.27 no.1
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• pp.1-6
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• 2014

Purpose: The purpose of this study was to investigate the effect of oral health education on adolescents. Methods: The subjects were middle school students in a health promoting school in Gunpo, Gyeonggi Province. Before giving the students oral health instruction, their modified Patient Hygiene Performance index (PHP index) was measured using disclosing solution. Then, the students were taught the right way to brush teeth (Rolling method) and use oral hygiene devices such as dental floss, tongue cleaner and interdental brush. Their modified PHP index was re-measured three days after and seven days after the education to evaluate the effect and persistency of oral health education. of the total 116 students, 48 students who completely filled out the questionnaire and participated in the whole process, photo shooting and three times of PHP index measurement, were included in the final analysis. Results: The students' modified PHP index significantly decreased three days after the education. However, the index slightly went back up seven days after the oral health education. Conclusion: Oral health education was effective in reducing dental plaque which remained after brushing. Continuous education about and constant motivation for oral hygiene turned out to be critical to maintain the impact of oral health education. Therefore, it is necessary to develop educational contents which can constantly motivate teenagers.

• Journal of dental hygiene science
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• v.5 no.2
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• pp.45-49
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• 2005

This study is designed to present basic materials necessary for offering the more effective way of dental hygienists, or those who are in charge of the education of Oral health, the treatment and prevention of dental problems, educating Oral health by stage by dint of determining the actual condition of the knowledge and management of dental hygiene, or prevention of the basic dental disease except the professional methods of dental management and evaluating their abilities to manage dental hygienes. In terms of the real conditions of the management of dental hygienes, the majority of the subjects said, "not bad" or "healthy". Most of them (62.1%) said that they brush their teeth three times a day, and most of them (85.2%) depend on rolling methods. 69.2% of them used brushes that are neither hard nor soft, and 28.4% of them use soft brushes and 49.7% of them brush their teeth for about 3 minutes. In terms of brushing time, 27.8% of them brush their teeth after lunch, while 23.8% of them brush their teeth after breakfast. 66.3% of them use fluoric tooth pastes while 19.5 percent of them said, "I have no idea." and 14.2% of them said, "No." In terms of complementary dental hygiene goods, dental goggles are used by 23% of them, and dental threads are used by 78.1% and tooth brushes are used by 78.1% of them, and 42.4% of the subjects use the instruments one to twice a day, and 53.8% of them use them for less than one minute a time. In terms of dental health care, 17.2% of them have a chew of gum and 8.3% of them pay a regular visit to dental clinics and 5.3% of them don't smoke.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.159-165
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• 2015

A self-administered survey was conducted on the dental hygiene students at three different colleges located in Gyeonggi Province and South Chungcheong Province respectively from October, 2013, to the same month of 2014 to grasp their oral health management behavior, differences in plaque index according to plaque index systems and the correlation of the two. And their plaque index was measured. The findings of the study were as follows: 62.8% of the respondents replied they got a dental checkup over the past year, and 84.1% answered they received preventive dental treatment once at least or more. 80.5% replied they used a fluorine-containing dentifrice. 90.9% answered they used the rolling method to brush their teeth, and 50.0% replied it took three minutes to brush their teeth. They got a mean of 27.88 when O'leary index was used among plaque index systems. Their PHP index and PHP-M index were respectively a mean of 1.30 and a mean of 12.12. Their plaque index became lower when they spent more time brushing their teeth, and the toothbrushing time made a statistically significant difference to that (p<0.05). The factor that exerted the largest influence on plaque index was whether to brush teeth for the sake of oral health (B=-9.747, t=-3.752, p<0.001) or not. That made a statistically significant difference to it. The above-mentioned findings illustrated that more patients visited dental clinics than before to receive preventive dental treatment or to get dental checkups, and that toothbrushing time and whether to brush teeth for the sake of oral health or not were identified as the oral health management behaviors to affect plaque index.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2629-2635
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• 2011

This study carried out questionnaire survey and experiment on oral hygiene effects according to the actual condition of using oral care products and the amount of toothpaste used targeting 40 freshmen and sophomores in dental hygienics in some universities from November 8, 2010 to November 26. The collected data was analyzed by using SPSS WIN 15.0 program. The following conclusions were obtained. 1. The result of actual condition of toothbrushing is as follows. As the answer of a question about whether or not toothbrushing after every meal at ordinary times, the largest was 47.5% of being average. The occasion of toothbrushing before going to bed at ordinary times was the largest with 47.5%. The daily toothbrushing frequency was 3 times mostly and the general toothbrushing method at ordinary times was a rolling method. The frequency of exchanging toothbrushes for the past 1 year was 3 times, which is the largest with 45.0%. 2. As a result of the actual condition of using oral care products, the majority of students don't use electric toothbrush, interdental brush, or mouth-rinse except dental floss. Accordingly, there need to be education and promotion with diverse methods so that a patient oneself can prevent oral disease by selecting and using oral care products that are proper for each individual. Also, it was indicated that there is no big difference in oral hygiene effects depending on the amount of toothpaste used. Thus, to avoid wasting toothpaste, we need to educate and promote to use the amount of toothpaste under 0.3g.

• Journal of dental hygiene science
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• v.7 no.3
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• pp.141-146
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• 2007

A questionnaire survey of patients for practical training of dental hygiene department of E college was conducted from August 28th 2006 to December 8th 2006. Before scaling, the purpose of the study and the questionnaires were fully explained and the patients were requested to complete the questions personally. The survey were conducted under their consent and 256 copies were collected and used for the analysis. The survey shows the patients' habit for oral health care according to the gender and age and their standards for the quality of life. 1. For gender, male occupied 117(45.7%) and female occupied 139(54.3%). For age, 158 of the patients were in their twenties(61.7%) and 60 of them were aged from 10 to 19(23,4%). 16 patients were aged from 40 to 49(6.3%) and 11 patients were aged from 30 to 39(4.3%) and the number of patients who are older than 50 was 11(4.3%). 2. For the mouth health care, according to gender, 37.6% of male answered that they had scaling and 46.8% of female patients answered that they had scaling experiences. Without distinction of gender, most patients answered they brushed their teeth twice a day. For 91.5% of male patients and 89.9% of female patients answered that they brushed their teeth after meals. Also, 41% of male patients and 53.2% of female patients use rolling method. For using mouth aids, 68.4% of male patients and 65.5% of female patients do not use any aids. 3. For brushing way, most teenagers and patients in their twenties use rolling method and patients older than thirty use vertical and horizontal method. The frequency of brushing shows that most of the respondents brush their teeth twice a day after meals. 4. The standard of quality of life according to gender, under 'clear pronunciation' head, male patients mark 4.42 points and female patients mark 4.17 points. Under 'every day going out' head, male patients mark 4.53 points and female patients mark 4.29 points. Under 'maintenance of emotion' male patients mark 4.27 points and female patients mark 4.27 points. 5. The standard of quality of life according to age, teenage patients show 4.28 points under 'having meals' and under 'clear pronunciation' head, patients in their forties mark 4.44 points. Under 'keeping teeth or denture clean' head, patients in their thirties mark 4.55 points. Patients in their fifties show the lowest grades in most questionnaires.