• Annals of Geriatric Medicine and Research
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• v.22 no.4
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• pp.194-199
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• 2018

Background: The aim of this study was to examine the correlation between the number of remaining natural teeth (NRT) and the appendicular skeletal muscle mass index (SMI) in older adults. Methods: This study was based on data from the 2008-2010 Korea National Health and Nutritional Examination Surveys. The participants were 2,378 older participants (984 men and 1,394 women) aged over 65 years. Survey dentists conducted oral health examinations, and ASM was measured using dual-energy X-ray absorptiometry. Results: The participants with $NRT{\geq}20$ had more ASM and SMI than those with NRT<20 in both sexes. SMI was correlated with NRT in men (r=0.018, p<0.001) and in women (r=-0.007, p<0.001). The positive correlation between the NRT and SMI remained significant in men even after adjusting for age, marital status, income, smoking, drinking, physical activity, protein intake, energy intake, calcium intake, body mass index, fasting blood glucose level, medications, and prostheses (${\beta}=0.011$, p=0.001). In women, the correlation disappeared after adjustment for smoking, alcohol, physical activity, protein intake, energy intake, calcium intake, marital status, income, fasting basal glucose, medication administration, and prostheses. Conclusion: This study showed a correlation between NRT and SMI in those ${\geq}65$ years of age in Korea. The relationship persisted in men, but not in women, even after adjusting for confounders.

• Journal of Korean Academy of Nursing
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• v.40 no.5
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• pp.747-755
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• 2010

Purpose: This study was conducted to investigate the degree of dry mouth and oral health-related quality of life and to identify factors contributing to oral health-related quality of life for community-dwelling elders. Methods: A descriptive correlational study design was used. Participants were 156 older adults from two senior welfare centers. Data were collected on February 21, 22 and 29, 30, 2009 using structured questionnaires. Enter type multiple regression analysis was used to identify factors influencing oral health-related quality of life according to general and oral health characteristics. Results: There were significant differences in oral health-related quality of life according to living arrangement, insurance, smoking, number of natural teeth, and denture type. The oral health-related quality of life had significant correlations with the number of chronic disease, number of medications, and dry mouth. Factors influencing oral health-related quality of life for community-dwelling older adults were dry mouth, number of chronic disease, and medical aid, which explained about 47.9% of total variance. Conclusion: These results indicate that in order to promote oral health-related quality of life for older adults, prevention or management of chronic diseases as well as oral health and dry mouth are needed for this population, and especially economically poor elders.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.181-189
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• 2019

Background: Edentulism is associated with socioeconomic status, rural residence, and chronic disease, but no studies have investigated edentulism and residence factors together. All information that drives a better understanding of the factors related to edentulism plays an important role in the planning and delivery of appropriate dental services for the elderly by national and oral health professionals. This study was designed to investigate the prevalence of edentulism in adults aged over 60 years in Korea and to examine whether there are differences in dentate status between people living in urban and rural areas after controlling for sociodemographic and other related factors. Methods: The data for this study were collected from 2013 to 2015 as part of the Korea National Health and Nutrition Examination Survey VI, those individuals aged over 60 years and who had complete datasets were included (5,071). The number of teeth and residence status were categorized into two groups: edentate and dentate (1 or more); urban and rural. Multiple multivariate logistic regression analyses were sequentially applied to assess the association between dentate status and residence status after adjusting for potential confounders. Results: Rural areas, lower household income, and lower education levels were associated with a higher edentate rate. The number of teeth was lower in rural areas than in urban areas. After adjusting for various factors, statistically significant associations were present for women, low household income, low education level, poor perceived health status, and alcohol consumption in participants. Conclusion: Elders living in rural areas had poorer oral health than elders living in urban areas. The government will need to provide effective systems for promoting oral health for elders living in rural areas.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.51-62
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• 1980

A Scanning Electron Microscope study was conducted to compare the effectiveness of mechanical preparation of the root canal in conjunction with a few number of canal irrigants that have been widely used for canal treatment. The irrigants used in this study were 5% sodium hypochlorite, 3% hydrogen peroxide, 15% EDTA, and 30% hydrochloric acid. The root canals of 84 freshly extracted teeth with single or multi root were conventionally prepared with Hedstroem files. 78 canals were irrigated with normal saline solution following each instrument number and 6 canals were prepared without irrigation. After instrumentation 72 canals were flushed with various irrigants for predetermined length of time as shown on the Table 1. Additional 20 teeth were kept uninstrumented and five of them were immersed in 15% EDTA for 5 minutes, five in 5% sodium hypochlorite for 5 minutes, five in 3% hydrogen peroxide for 20 minutes, and the last five were only rinsed with saline solution. The SEM examination revealed as follows: 1. The canal wall cannot be thoroughly prepared by means of files. 2. No typical structural changes occured on instrumented dentin surface by saline solution, 3% $H_2O_2$, 5% NaOCl, within 5 minutes. 3. 5% NaOCl Solution showed excellent solvent effect to organic substances in uninstrumented canal within 5 minutes and 15% EDTA and 3% $H_2O_2$ showed unsignificant changes. 4. 15% EDTA and 30% HCl dissolved calcified debris and dentin chips that obturated the dentinal tubules and showed patent orifices. 5. 15% EDTA affected on peritubular dentin more readily and showed concavity around dentinal tubules.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.145-157
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• 2000

Cytotoxic substances in dental calculus and root cementum of periodontally diseased teeth inhibit new attachment and regeneration. The purpose of scaling and root planing is to remove pathologic structures harboring these cytotoxic substances in order to create a biologically acceptable root surface. However, these procedures inevitably leave a non-biocompatible smear layer. Conventionally, the smear layer has been removed with low pH etching agents such as citric acid, phosphoric acid and tetracycline hydrochloride(TC). Lately, a supersaturated neutral pH etching solution of ethylene diamine tetraacetic acid(EDTA) has been found to be as effective as low pH etchants with respect to smear removal and to be superior in exposing root surfaceassociated collagen. The aim of the present study was to determine the effect of root surface treatment using EDTA on the initial attachment of human gingival fibroblasts. 27 human teeth, extracted due to severe periodontitis, were cut into dentin slices after root planing. The specimens were divided into TC group(treated with $50㎎/m{\ell}$ tetracycline-HCl, pH 1.52), EDTA group(treated with 17% EDTA, pH 7.4), and non-treated control group. After sterilization, 5th subcultured human gingival fibroblasts were seeded in each culture well containing a prepared root slice and incubated for 15 min., 60 min., and 4 hours in 5% $CO_2$ incubator at $37^{\circ}C$. At each incubation time, the number of attached fibroblasts were counted on the microphotographs taken at a magnification of x100. The difference of the number of attached cells between groups was statistically analyzed by the ANOVA followed by Duncan test in SPSS/PC＋programs. The results were as follows : 1. After incubation for 15 min, the attached cells were significantly more in EDTA group and TC group than non-treated control group(p<0.05), but there was no significance in the difference between EDTA group and TC group(p>0.1). 2. After incubation for 60 min and 4 hours, there was no significant difference in the number of attached cells between all groups(p>0.1). 3. In both EDTA group and TC group, there was no significant difference in the number of attached cells between different incubation(p>0.1). But in control group, the number of attached cells was significantly increased after incubation for 60 min, compared with incubation for 15 min(p<0.05). The above results suggest that root surface treatment using EDTA could enhance the initial attachment of gingival fibroblasts to root surface as effective as tetracycline-HCl.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.7-16
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• 1986

The purpose of this study was to examine the distribution and the bond failure of the acid-etched ceramometal retainer (Maryland Bridge). 126 subjects who treated by faculty and residents of Department of Prosthodontics, Seoul National University Hospital from Dec. 1982 to Dec. 1986 were selected for this study. From the foregoing study author obtained the following conclusions. 1. A total of 135 restorations were placed in the mouths of patients ranging in age from 11 to 10 years (man 62, woman 64). 2. Most restorations were applied to replace anterior teeth. 3. It was found that of the total number of bridges constructed 59.3 percent were the three-unit type. 4. Replacing one tooth mining was the most frequent cases (74.1 percent). 5. Of the total number of cases, 10.4 percent stowed bond failure. 6. The bond failure, author suggest, be due to one or more of mis-fit of framework, occlusion, material in itself, faulty case selection and lack of technique.

• The Journal of the Korean dental association
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• v.25 no.6 s.217
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• pp.578-587
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• 1987

The purpose of this was to examine the distribution and the bond failure of the acidetched ceramometal retainer (Maryland Bridge). 126 subjects who treated by faculty and residents of Department of Prosthodontics, Seoul National University Hospital from Dec. 1982 to Dec. 1986 were selected for this study. From the foregoing study author obtained the following conclusions. 1. A total of 135 restorations were placed in the mouths of patients ranging in age from 11 to 70 years (Man 62, woman 64) 2. Most restorations were applied to replace anterior teeth. 3. It was found that of the total number of bridges constructed 59.3 percent were the three-unit type. 4. Replacing one tooth missing was the most frequent cases(74.1 percent). 5. Of the total number of cases, 10.4percent showed bond failure. 6. The bond failure, author suggest, be due to one or more of mis-fit of framework, occlusion, material in itself, faulty case selection and lack of technique.

• Animal Systematics, Evolution and Diversity
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• v.28 no.4
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• pp.221-229
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• 2012

Paranebalia longipes (Willemoes-Suhm, 1875) is cosmopolitan and has been usually found in the algal and sponge debris on the sandy mud substrates. This species can be clearly distinguished from other species of Paranebalia by the presence of serration on posterior margin of pleopods, the number of articles on antennule and antenna, and number of teeth on flange of antennule fourth article. The genus Paranebalia is new to Korea. In this paper, we provide detail descriptions of the diagnostic characteristics and illustrations of the P. longipes. Additionally, type locality and world distribution of the genus Paranebalia are provided.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1775-1780
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• 2003

A hybrid finite element analysis was used to analyze the influence of ring gear rim thickness and spline number on the static properties of an epicyclic gear system with manufacturing errors. Both of these parameters affected the bearing force and critical stress. The effect of changes in the rim thickness on the load sharing between the gears depended on the type of manufacturing error. Ring flexibility improved the load sharing between planetary gears only in systems with planet tooth thickness or planet tangential errors; for other types of error, ring flexibility worsened the load sharing. To improve load sharing, rim thickness and spline number should be controlled within a specific range. The effect of the ring gear boundary condition was more apparent in a system with errors than in a normal system.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.48-53
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• 1999

In this paper, a practical method for design and machining of cycloid gear was investigated. Based on the proposed method, a systematic program was developed for automatically designing the tooth profiles of epicycloid and hypocycloid gears for the case fo one difference between the number of teeth of cycloid gear and the number coordinates of tooth profiles and pressure angles. The error analysis between cycloid curve and Biarc curve was performed to show the effective method of equidistant partitioning of cycloid curve so that efficient method of Biarc curve fitting was also proposed for the partitioned curve.