• Journal of Korean society of Dental Hygiene
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• v.17 no.5
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• pp.875-887
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• 2017

Objectives: The objective of this study is to provide basic data needed in developing an educational program designed to upgrade capacity and awareness of preventive dental treatment among oral health workers, by analyzing levels of awareness of preventive dental treatment and educational needs among dentists and dental hygienists. Methods: The collected data was analyzed with SPSS program ver. 19.0. The data was under t-test. Results: The frequency level of giving preventive dental treatment to patients among dentists and dental hygienists is below mid-point, 3 on the 5-point Likert scale. In terms of frequency level per item, scaling & polishing was ranked the highest, followed by periodontal maintenance, tooth-brushing instruction, and prescription and instruction of oral care product in descending order. On the questions asking how important preventive dental care they perceive to be, both dentists and dental hygienists perceived it to be highly important. When they were asked to rank those items by the importance of education, they considered periodontal maintenance as the most important one, followed by individual education of oral health, incremental oral health care, scaling& polishing, toothbrushing instruction, and prescription and instruction of oral care product. Respondents pointed out problems in running a preventive dental treatment program as follows: overwork, lack of dedicated workforce, un-fixed costs, and lack of necessary equipment. When they were asked to point out items needed to run such a program, the largest number of respondents indicated dedicated workforce placement, followed by improving awareness of the customer, and improving awareness of the dental workers. Conclusions: In order to effectively run a preventive dental treatment program, it is necessary for oral health workers to clearly understand the concept of it. It is also necessary to develop and operate an education program on preventive dental treatment targeting oral health professionals.

• Environmental Engineering Research
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• v.24 no.3
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• pp.418-426
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• 2019

Current available commercial membranes are not robust and are therefore destroyed if left to dry out or handled roughly. Woven fibre microfiltration (WFMF) membranes have advantages over its competitors with respect to durability, thus, favourable for the developing economies and operation during rough conditions. Evaluation of the effects of aeration and brushing as a flux enhancement strategies for WFMF membrane was the purpose of this study. The WFMF membrane was found to be susceptible to pore plugging by colloidal material and adsorption/attachment by microbiological contaminants. This led to a 50% loss in flux. Aeration as a single flux enhancement strategy proved insufficient to maintain high flux successfully. Therefore combined flux enhancement strategies yielded the best results.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.54-61
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• 2016

The use of advanced composite materials in strengthening and repair of existing structures is increasing rapidly. This paper describes an effectiveness of a bonding of carbon fiber reinforced sheets to corroded steel members for the repair. Three types of surface treatment, what we call cleaning, of corroded plate are chosen as parameters. They are "without cleaning","removal of painting by brushing" and "complete removal of painting". From the experimental study, the following findings are obtained. 1) When the steel plate is subjected to tensile force, carbon fiber sheets adhered to the painted steel gives a higher strength against peeling compared to that of the plate without painting, 2) The grade of surface treatment, or cleaning of the corroded steel plate affects the strengthening effect.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.533-539
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• 1994

The mandibular buccal frenum is a fold of mucous membrane at the posterior labial vestibule, that attaches the lips and the cheeks to the alveolar mucosa, gingiva, and underlying periosteum. The buccal frenum becomes a problem if its attachment is too close to the marginal gingiva. It may then pull on healthy gingiva, encourge plaque formation and interfere with tooth brushing. Heavy buccal frenum mucogingivally results in insufficient attached gingiva, inadequate vestibular depth and high frenum attachment and also difficulty in eruption of mandibular second premolar. Frenectomy in various forms has been used for many years to remove the influence of the frenum. Unfortunately, the results are not always ideal and there is often postoperative relapse because of muscle pull. In this treatment, frenotomy was used in conjuction with autogenous free gingival graft with the object of removing the influence of the buccal frenum and creating an adequate and stable width of attached gingiva. We observed decrease in muscle pull, adequate width of attached gingiva and increased vestibular depth in addition to progressive eruption of second premolar. Periodic follow-up is needed for evaluation of relapse, grafting gingiva and also space regaining for second premolar.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.177-186
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• 2006

The purpose of this study was to obtain baseline data for establishing oral health policy and developing oral health among industrial workers. A question was used to question paper 226 workers of D heavy industrial company in Sacheon-City. The result obtained were as follows: 1.Generally dental patients asked to not prevention treatment but treatment of dental disease. 2.Most of workers respondent that their oral health is so so.(52.2%). 3.Respondents reported 76.1% of dental calculus, 55.8% of sensitive to cold and hot things. 4.Oral health attitude is tooth brushing experience (39.8%), scaling experience (75.7%), when brushed area all teeth, gingiva and tongue(47.3%). 5.81.8% of respondents received no teeth pain when brushing time is over 3 minutes and 83.7% of smokers had calculus.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.125-139
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• 2009

Objective : This study was performed in order to provide basic data for halitosis prevention and establish a device to efficiently eliminate halitosis and to analyze the factors that affect the halitosis. Methods : Oral examination on the Gingival index, CPITN, Tongue Plaque index, and OHI-S as well as halitosis measurement among 293 rural residents. Results : Gingival index was high at mild on female and at moderate on male(p=0.025). Sorting the result by age, mild was 54.1% in the 40s, and moderate was 49.5%, 42.0% and 70.0% each in the 50s, 60s, and the 70s(p=0.005). The need for dental plaque management was 100%. The need for scaling was high with 78.3%, 93.0%, 89.9%, and 90.0% each for the 40s, 50s, 60s, and 70s. The need for complex periodontal treatment was also high with 32.4%, 47.5%, 48.7% and 60.0%, each for the 40s, 50s, 60s, and 70s(p=0.050). The highest bad condition for OHI-S was 69.5%, and good being 18.9%, and very bad being 11.6%. For moderate tongue plaque index was 74.4% as the highest. As the level of education increased, the slight tongue plague was increased, but in contrast, the moderate and higher tongue plague index was decreased(p=0.010). OG under 50ppm was 61.1% on male and OG over 50ppm was 50.9% on female(p=0.041). In OG over 50ppm, CPITN was 52.1% and 41.9% in scaling and complex periodontal treatment group(p=0.018). OHI-S, in bad and very bad condition with OG, over 50ppm, was 48.7% and 46.9%(p=0.019). The higher tongue plague index showed significant amount of increase at OG and EG above 50ppm(p=0.006). $NH_3$, as the tongue plaque index increased, the wider range of distribution was shown(p=0.000). As for the multiple regression analysis result, there have been selected females and tongue plaque index as factors affecting OG. There have been selected age and tongue plaque index as factors affecting EG and there have been selected females as factors affecting on $NH_3$. Conclusions : With the aforementioned results in mind, the status of halitosis among rural residents is considered to bare a close relation with oral environments. we have to focus on correct tooth brushing methods and tongue brushing, with using tongue cleaner to remove fur of tongue plaque. Also, in order to analyze exactly the factors of individual halitosis, we need continuous and systematic study.

• Korean Journal of Materials Research
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• v.26 no.7
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• pp.388-392
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• 2016

A cold roll-bonding process was applied to fabricate an AA1050/AA6061/AA1050 laminate complex sheet. Two AA1050 and one AA6061 sheets of 2 mm thickness, 40 mm width and 300 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 1.2 mm in thickness by conventional rolling. The rolling was performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 5.0 m/sec. The AA1050/AA6061/AA1050 laminate complex sheet fabricated by roll bonding was then hardened by natural aging T4) and artificial aging (T6) treatments. The microstructures of the as-roll bonded and the age hardened Al complex sheets were revealed by optical microscope observation; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the as-roll bonded complex sheet was found to increase by 2.9 times compared to that value of the starting material. In addition, the hardness of the complex sheets increased with cold rolling for AA1050 and age-hardening treatment for AA6061, respectively. After heat treatment, both AA1050 and AA6061 showed typical recrystallization structures in which the grains were equiaxed; however, the grain size was smaller in AA6061 than in AA1050.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.392-397
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• 2019

A cold roll-bonding process is applied to fabricate an AA6061/AA5052/AA6061 three-layer clad sheet. Two AA6061 and one AA5052 sheets of 2 mm thickness, 40 mm width, and 300 mm length are stacked, with the AA5052 sheet located in the center. After surface treatment such as degreasing and wire brushing, sample is reduced to a thickness of 1.5 mm by multi-pass cold rolling. The rolling is performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 400 mm at rolling speed of 6.0 m/sec. The roll bonded AA6061/AA5052/AA6061 complex sheet is then hardened by natural aging(T4) and artificial aging(T6) treatments. The microstructures of the as-roll bonded and age-hardened Al complex sheets are revealed by optical microscopy; the mechanical properties are investigated by tensile testing and hardness testing. After rolling, the roll-bonded AA6061/AA5052/AA6061 sheets show a typical deformation structure in which grains are elongated in the rolling direction. However, after T4 and T6 aging treatment, there is a recrystallization structure consisting of coarse equiaxed grains in both AA5052 and AA6061 sheets. The as roll-bonded specimen shows a sandwich structure in which an AA5052 sheet is inserted into two AA6061 sheets with higher hardness. However, after T4 and T6 aging treatment, there is a different sandwich structure in which the hardness of the upper and lower layers of the AA6061 sheets is higher than that of the center of the AA5052 sheet. The strength values of the T4 and T6 age-treated specimens are found to increase by 1.3 and 1.4 times, respectively, compared to that value of the starting material.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.161-167
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• 2022

A cold roll-bonding process is applied to fabricate an AA6061/AA5052/AA6061/AA5052 layered sheet. Two AA6061 and one AA5052 sheets of 2mm thickness, 40mm width and 300mm length are alternately stacked, then reduced to a thickness of 2.0 mm by multi-pass cold rolling after surface treatment such as degreasing and wire brushing. The rolling is performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 400 mm at a rolling speed of 6.0 m/sec. The roll-bonded AA6061/AA5052/AA6061/AA5052 layered sheet is then hardened by natural aging (T4) and artificial aging (T6) treatments. The microstructure of the as-roll bonded and the age-hardened Al sheets was revealed by SEM observation; the mechanical properties were investigated by tensile testing and hardness testing. After T4 and T6 aging treatment, the specimens had a recrystallization structure consisting of coarse equiaxed grains in both AA5052 and AA6061 regions. The as-roll-bonded specimen showed a clad structure in which the hardness of AA5052 regions was higher than that of AA6061 regions. However, after T4 and T6 aging treatment, specimens exhibited different structures, with hardness of AA6061 regions higher than that of AA5052 regions. Strengths of T6 and T4 age-treated specimens were found to increase by 1.55 and 1.36 times, respectively, compared to the value of the starting material.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.705-715
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• 2010

Objectives : This study is aimed to seek how to promote oral health care by leading the clients with dental fears to change their behaviors in oral hygiene care based on the analysis of the relationships between the dental fears and oral health care behaviors of the clients who visit the Dental Hygiene Education Room. Methods : This study analyzed the 361 dental hygiene records of the subjects with finished treatment and accurate records among a total of 370 clients who had received dental hygiene care at the Dental Hygiene clinic in Y University from March 2007 till June 2009. According to their general features, the study analyzed whether they had any dental fears and why such fears occurred and conducted Chi-square test to compare their oral hygiene care experiences and behaviors with dental fears. Data analysis was made using the SPSS 12.0K for Window, with level of significance set at 0.05. Results : 1. In terms of dental fear or non-fear, the comparison by gender showed that women had a higher level than men, with 76 women(47.2%) answering yes; the comparison by age showed that the age group of 30 years old or older had a higher level than other groups. 2. In terms of dental fear reasons, "the past pain experiences" recorded 34.2%, showing the highest rate. 3. In addition, dental fears had influences on regular dental examination, scaling and dental hygiene education and the subjects without dental fear showed higher levels in terms of tooth-brushing frequency and time. Conclusions : To control "the past pain experiences", future dental treatment should place priority on preventive treatment and get clients to cope with pains through the preliminary education with pains. Besides, to make an effective oral health care of the clients with dental fears, dental hygienists should control the fears of the clients and perform an appropriate oral health care for them using the communication techniques to make friendly and trustworthy impressions.