• Journal of Korean society of Dental Hygiene
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• v.10 no.6
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• pp.1001-1014
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• 2010

Objectives : The purpose of this study is about discovering the basic references to find the ways to vitalize handicapped dental clinics. Methods : The study was analyzed by the satisfactions of those patients who took the advantages of using the dental care at B-welfare center and also their transformed perceptions after the services are influenced. The analysis was the questionnaire consisting of 100 items and survey data. Results : 1. The satisfaction of the dental service for the disabled was respectively high which was the average of 4.49. 2. Their satisfactions of receiving kindness services by volunteers and employees were the highest in the entire research of successful handicapped dental services and it was 4.78 overall. 3. The satisfaction of using handicapped dental clinic has the higher range of female users than male's. In the mean time treatment details of the dental care and the satisfaction towards to the volunteers and faculty at the center show the statistical significance gap. 4. The oral care service after experiencing the dental clinic for handicapped relived their discomforts of using the regular dental clinic which shows their highest satisfaction as it is the point of 4.75. 5. the change perception after dental treatment for handicapped has the higher range of females than men's and solving the problems of mouth reference and discomfort of using regular clinics show the statistical significance gap. 6. In the change perception after having dental treatment for handicapped the thought of the possibility of periodical dental care shows the highest perception when the number of visiting is usually shorter and it shows the statistical significance. Conclusions : According to the satisfaction of those inpatients who use free dental care services that belong to dental clinics for handicapped in a part of Seoul welfare centers human services were appeared as the most important factor due to their advantages of taking services from volunteers and staff members. On the other hand to enhance the medical treatment information and environment which showed the weakest factors each inpatient should be specifically specialized for their needs and also further study on plans which enhance their perceptions toward to a better quality of oral-related life is required after using dental treatment service.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.86-94
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• 2005

The purpose of this study was to measure the flexural strength and hardness of four core materials in 4 different medias and to evaluate the relationship between the physical properties. For the flexural strength, the specimens were prepared from each of the following materials: Bisfil Core, Core Max, Fuji IX GP, Miracle Mix and randomly divided into four groups and stored at 37 degree C in the following medias: distilled water for 24 hours (DW/1), distilled water for 30 days (DW/30). $2%$ NaF for 30 days (NF/30), 0.02N lactic acid for 30 days (LA/30). After storage, the specimens were subjected to flexural strength testing and calculated to flexural modulus. For hardness testing, specimens were prepared from four materials and storaged in the uniform way. After storage, the specimens were subjected to Vicker's hardness testing. 1. The flexural strength of Core Max were the highest, and the flexural strength of Miracle Mix were the lowest. 2. The hardness of Bisfil Core were the highest. 3. The hardness of Core Max were the highest. 4. The hardness of Miracle Mix were the lowest. 5. $2\%$ NaF and 0.02N lactic acid negatively affected the flexural strength and hardness of four core materials.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.6
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• pp.384-390
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• 2012

Purpose: The purpose of this study is to examine in vivo osteogenesis of cultured human periosteal-derived cells and polydioxanone/pluronic F127 scaffold. Methods: Two one-year-old miniature pigs were used in this study. $2{\times}10^6$ periosteal-derived cells in 1 mL medium were seeded by dropping the cell suspension into the polydioxanone/pluronic F127 scaffold. These cell-scaffold constructs were cultured in osteogenic Dulbecco's modified Eagle's medium for 7 days. Under general anesthesia with azaperone and tiletamine-zolazepam, the mandibular body and ramus of the pigs were exposed. Three bony defects were created. Polydioxanone/pluronic F127 scaffold with periosteal-derived cells and the scaffold only were implanted into each defect. Another defect was left empty. Twelve weeks after implantation, the animals were sacrificed. Results: New bone formation was clearly observed in the polydioxanone/pluronic F127 scaffold with periosteal-derived cells. Newly generated bone was also observed in the scaffold without periosteal-derived osteoblasts and empty defect, but was mostly limited to the periphery. Conclusion: These results suggest that cultured human periosteal-derived cells have good osteogenic capacity in a polydioxanone/pluronic F127 scaffold, which provides a proper environment for the osteoblastic differentiation of these cells.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.129-142
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• 2002

Epithelial-mesenchymal interaction plays a important role in cell growth and differentiation. This interaction is already well known to have an importance during the organ development as well as cell growth and differentiation. However, in vitro experimental model is not well developed to reproduce in vivo cellular microenvironment which provide a epithelial-mesenchymal interaction. Because conventional monolayer culture lacks epithelial-mensenchymal interaction, cultivated cells have an morphologic, biochemical, and functional characteristics differ from in vivo tissue. Moreover, it's condition is not able to induce cellular differention due to submerged culture condition. Therefore, the aims of this study were to develop and evaualte the in vitro experimental model that maintains epithelial-mesenchymal interaction by organotypic raft culture, and to characterize biologic properties of three-dimensionally reconstituted oral keratinocytes by histological and immunohistochemical analysis. The results were as follow; 1. Gingival keratinocytes reconstituted by three-dimensional organotypic culture revealed similar morphologic characteristics to biopsied patient specimen showing stratification, hyperkeratinosis, matutation of epithelial architecture. 2. Connective tissue structure was matured, and there is no difference during stratification period of epithelial 3-dimensional culture. 3. The longer of air-exposure culture on three-dimensionally reconstituted cells, the more epithelial maturation, increased epithelial thickness and surface keratinization 4. In reconstitued mucosa, the whole epidermis was positively stained by anti-involucrin antibody, and there is no difference according to air-exposured culture period. 5. The Hsp was expressed in the epithelial layer of three-dimensionally cultured cells, especially basal layer of epidermis. The change of Hsp expression was not significant by culture stratification. 6. Connexin 43, marker of cell-cell communication was revealed mild immunodeposition in reconstitued epithelium, and there is no significant expression change during stratification. These results suggest that three-dimensional oragnotypic co-culture of normal gingival keratinocytes with dermal equivalent consisting type I collagen and gingival fibroblasts results in similar morphologic and immunohistochemical characteristics to in vivo patient specimens. And this culture system seems to provide adequate micro-environment for in vitro tissue reconstitution. Therefore, further study will be focused to study of in vitro gingivitis model, development of novel perioodntal disease therapeutics and epithelial-mensenchymal interaction.

• Journal of Korean Dental Hygiene Science
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• v.2 no.1
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• pp.41-50
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• 2019

Education should consider the social consensus that changes according to the times and the social environment, and it is also necessary to consider the technically useful subjects. We collected and reported the 4-year course curriculum of dental hygiene when Korean dental hygiene education has continued over 50 years. Each 4-year course curriculum was collected by searching each university website, or requested by email. The curriculum of 23 among 27 schools was collected. According to the classification of dental hygiene in the dental hygienist national examination classification or the Korean society of dental hygiene science, the subjects of the course were divided into clinical dental hygiene, clinical dental treatment support, basic dental hygiene, social and educational dental hygiene, and collected 23 curriculum courses. The average major curriculum was 104.9 credits and the average number of subjects in major courses was 34.3. The average subjects' number of clinical dental hygienic courses was 33.9 (37.5% of the total major credits), clinical dental treatment support was 30.6 (30.2% of the total major credits), basic dental hygiene was 21.8 (20.8% of the total major credits), and social and educational dental hygiene courses was 13.6 (13.0% of total major credits). Integrated subjects' name in clinical dental hygiene was used in all schools of the survey, such as clinical dental hygiene education (and practice), comprehensive dental hygiene education, and integrated dental hygiene. There were 13 schools (56.5%) that use the integrated name in clinical dental treatment support, such as clinical dentistry. There were 14 schools (60.9%) to open dental clinic management, and 22 schools (95.7%) to open national health insurance claims. The basic dental hygiene curriculum maintained the title of each subject and social and educational dental hygiene education was established in most schools, such as community dental health, oral health statistics, and oral health education. Other subjects were English conversation in dental clinic (8 schools) education, clinical dental treatment support, basic science in dental hygiene, social and educational dental hygiene. We knew the clinical dental hygiene and clinical dental treatment support were changing into the integrated subjects, and most schools run dental hygiene research.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.395-402
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• 2014

BACKGROUND: Azadirachta indica Extract(AIE) containing azadirachtin as active ingredient have been used worldwide as environment-friendly organic material having pest control properties. However, the extracts prepared with different solvent and from different plant site is very diverse and have different toxicity. METHODS AND RESULTS: In this study, the four week repeated oral dose toxicity test of aqueous AIE in Sprague-Dawley rats was carried out to investigate the toxic effect of liver, main toxicity target organ of AIE. The male and female rats were divided into 4 groups, respectively; control(0 g/Kg bw), low-dose group(0.5 g/Kg bw), middle-dose(1.0 g/Kg bw) and high-dose group(2.0 g/Kg bw). As a results, relative liver weight increased with dose-dependent of AIE(p<0.05). Serum LDH in all AIE-treated groups were significantly lower than the control in male rats(p<0.05). However, serum GOT and GPT were significantly increased in all male AIE-treated groups in male rats(p<0.05) and, in particular, increase of serum GPT in dose-dependent manner raise the possibility of liver damage. Even through serum GLU was increased significantly in high-dose group in male rats compared to control, there were no significant differences of urinary GLU among all groups(p<0.05). In addition, histopathological examination of the liver did not reveal any lesions in all AIE-treated groups. CONCLUSION: In conclusion, 4 weeks of the repeated oral administration of AIE 2.0 g/Kg to rats has resulted no toxic response in liver. Therefore, AIE was no indicated to have any toxic effect in the SD rats, when it was orally administrated below the dosage 2.0 g/Kg/day for 4weeks.

• Korean Journal of Environmental Agriculture
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• v.33 no.2
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• pp.103-110
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• 2014

BACKGROUND: Azadirachta indica has been widely used as environment-friendly organic materials because of its insecticidal properties. This study was carried out to investigate the acute toxicity and the subacute toxicity of Azadirachta indica extract(AIE) in rats. METHODS AND RESULTS: For the oral acute toxicity test, Sprague-Dawley rats were gavaged with 2.0 g/Kg bw of AIE. The $LD_{50}$ value was greater than 2.0 g/Kg bw for both male and female rats. For the subacute toxicity study, rats were treated with AIE at doses of 0.5, 1.0, 2.0 mg/Kg bw once a day for 4 weeks(n=10 animals per each group). There were no significant changes in body weight, food intake and water consumption observed during the experimental duration. In addition, no difference of relative kidney weight was observed among all treated groups. Serum creatinine level in the AIE 2.0 g/Kg group increased significantly compared with that of control group in male rats, but serum blood urea nitrogen was significantly decreased in a dose-dependent manner (p<0.05). Significant increase of serum cholesterol levels were observed in all AIE groups, compared with the control group, in the female rats (p<0.05). However, histopathological examination of the kidney did not reveal any significant lesions in all groups. CONCLUSION: On the basis of results, it could be concluded that oral administration AIE didn't cause any toxic response in kidney, except the increased serum cholesterol.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.555-565
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• 2010

Objectives : This study was intended to examine job satisfaction in dental hygienists working in the Gwangju Jeonnam area and provide basic materials for the efficient management of dental clinics and the improvement of working conditions in dental hygienists. Methods : In order to achieve this purpose, the questionnaire survey was conducted from August 13 to October 6, 2007. Of a total of 394 questionnaires, 34 was excluded because of poor responses and finally 360(Gwangju 296, Jeonnam 64) were analyzed. Results : For job satisfaction associated with the total career and turnover, satisfaction was increased with the total career. Job satisfaction associated with working conditions became higher as a monthly mean paycheck was increased or when an incentive, in the annual pay system and long-service men preference was provided(p<0.05). Job satisfaction was 3.26. The highest satisfaction at detailed factors was found in patient relation(3.85), colleague relation(3.40), prospects(3.26), dentistry organization(3.17), autonomy(3.10), and pay(2.78). For detailed factors of job satisfaction, the most influential factor was monthly mean paycheck, followed by incentive, age and marriage(p<0.05). Conclusions : When dental hygienists' working environment is planned and improved in the rational and desirable direction, their job satisfaction will be improved. As a result, it will contribute to a decrease in the jobless rate and an increase in the productivity of oral care and the efficiency of hospital management.

• Corrosion Science and Technology
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• v.17 no.2
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• pp.45-53
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• 2018

A new 80Ti-15Ta-5Zr wt% alloy surface was protected by anodic oxidation in phosphoric acid solution. The protective oxide layer (TiO2, ZrO2 and Ta suboxides and thickness of 15.5 nm) incorporated $PO{_4}^{3-}$ ions from the solution, according to high resolution XPS spectra. The AFM analysis determined a high roughness with SEM detected pores (20 - 50 nm). The electrochemical studies of bare and anodically oxidized Ti-15Ta-5Zr alloy in Carter-Brugirard saliva of different pH values and saliva with 0.05M NaF, pointed to a nobler surface for the protected alloy, with a thicker electrodeposited oxide layer acting as a barrier against aggressive ions. The oxidized alloy significantly decreased corrosion current densities and total quantity of ions released into the oral environment in comparison with the bare one, at higher polarisation resistance and protective capacity of the electrodeposited layer. The impedance data revealed a bi-layered oxidation film formed by: a dense, compact, barrier layer in contact with the metallic substrate, decreasing the potential gradient across the metal/oxide layer/solution interface, reducing the anodic dissolution and a more permissive, porous layer in contact with the electrolyte. The open circuit potential for protected alloy shifted to nobler values, with thickening of the oxidation film signifying long-term protection.

• The Journal of the Korean dental association
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• v.55 no.2
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• pp.139-155
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• 2017

The study of job satisfaction among female dentists is essential to improve the quality of their life. In this study, a job satisfaction survey of female dentists in Gwangju was performed and the factors affecting job satisfaction were examined. A survey of female dentists in Gwangju was conducted using a custom-designed and validated questionnaire which incorporated the Korean Dentist satisfaction Survey (KDSS) as well as questions regarding socio-demographics and professional characteristics. Satisfaction for each question was measured by a 5-point Likert scale. The final analysis was performed with 89 questionnaires, after excluding 3 non-response questionnaires. Analysis of the data for each group was carried out using a Mann-Whitney U test and Kruskal-Wallis H test. The reliability of the questionnaire was identified by the internal consistency of the survey using Cronbach coefficient. The data were statistically analyzed using SPSS (IBM SPSS Statistics 19, SPSS Inc, Chicago, Ill, USA). The level of statistical significance was set at p = 0.05. On analyzing with use of the above mentioned method, the following findings were observed: Income, leisure time, time for self-development, and overall job satisfaction were lower than the average, especially the percentage of dissatisfaction was much higher than that of satisfaction. Satisfaction was associated with age, duration of employment, and the number of assistants. The limitations of this study are the lack of an adequate sample size, convenience sampling during extraction, the lack of questionnaire items, the limitations of quantitative research, and failure to perform measurement in the non-response group. However, female dentists can be expected to achieve a more satisfactory and enhanced working environment if the research based on the current study is followed up in an expanded target group.