• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.100-110
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• 2017

Purpose: This paper describes the basic principles and the feasibility of the field of dental diagnosis of optical coherence tomography (OCT) used in diverse field of medical diagnosis. Materials and methods: In this review, the research data of OCT were searched from PubMed, medical journal and related papers. Results: Generally, OCT is noninvasive and is possible to secure an excellent spatial resolution and real-time images of biological microstructure. Conclusion: This review discusses not only the basic principles of operation, types, advantages, disadvantages of OCT but also the future applications of OCT technology and their potential in the field of dental diagnosis.

• Korean Journal of Social Welfare
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• v.64 no.4
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• pp.163-188
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• 2012

This study examines recent trends in income inequality among the elderly in Korea. Aggregate income inequality trends are explained by examining evidence from inequality index decomposition by population subgroup and by income source. Data come from Korean Labor and Income Panel Study(KLIPS). The results are as follows. First, elderly income inequality increased from 1999 to 2002, and then decreased until 2008. Second, household composition changes appear to have disequalizing influence. The proportion of elderly people who are economically dependent on non-elderly family member or living with adult children has declined. Equalizing influence of private transfers also decreased between 2002 and 2008. These results indicate that the redistributive role of family has weakened over time. Third, the improvement of education level and changing occupational structure among the elderly household head contributed to increase in elderly income inequality. Fourth, earning's factor share has declined steadily, and the diminishing role of earnings provides equalizing influence on elderly income inequality from 2002 to 2008. Fifth, the impact of recent expansion of social insurance has changed over time. Inequality contribution of social insurance income increased from 1999 to 2002, and then decreased from 2002 to 2008.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.193-199
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• 2000

The a-C : H films have been grown on the glass substrate by PECVD method, where plasma was generated with a 60 Hz line power source. The growth rate of films is found to be dependent of the partial pressure of $C_2H_2$. This growth rate is a little higher than that in which $CH_4$ instead of $C_2H_2$ is used. The transmittance is also much higher(95%). The optical energy gap of films is in the range of 1.4~1.8eV depending on the partial pressure of $C_2H_2$. However, this energy gap, which is 1.8eV, is found to be independent of the partial pressure of $C_2H_2$ for the thick films above $2000{\AA}$. The carbonization is checked from peak intensities of D ($sp^3$) and G($sp^2$) peaks in Roman spectra. The hydronization and C-H bonding status in films can also be determined from FTIR results. Both the bonding strength of C-H and the ratio of $sp^3$ to $sp^2$ in bonding are found to be slightly dependent of partial pressure of $C_2H_2$. Judging from above results, we can conclude that the best value for partial pressure of $C_2H_2$ in growing process of thick films is about 13.8%.

• Journal of agricultural medicine and community health
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• v.23 no.1
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• pp.27-38
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• 1998

Purpose : To assess knowledge levels of cancer warning signs, a descriptive study wad conducted in Chungju rural area. Materials and Methods : We conducted a population-based study of men women who were 30 years of age or older, living in a three myens of Chungju rural area. Of 8,026 residents in 3 Myens, 1,148 adults(30 years of age or older) were completed structured questionnaire survey from July 21, 1997 to July 26, 1997. 7 cancer warning signs were used to assess knowledge level of cancer warning signs. Results : Participants in this study were poorly informed about the cancer warning signs, and the 24.9% of participants and divided by two groups. The high level group was 19.3%, and the low 80.7%. In this initial univariate analysis, the following variables were significantly associated with knowledge levels of cancer warning signs: age, sex, education, living with parter, annual income, smoking status, hepatitis vaccination, perceived possibility of cancer, previous cancer-screening examinations. In multivariate logistic analysis, we found three variables, sex, education level, previous pap-smear test, are significantly associated with knowledge levels of cancer warning signs. The knowledge level was higher among women, people with higher education, and those who had previous pap-smear examination. Conclusion : This study demonstrates that cancer warning signs are not common knowledge among the rural public. It also indicates the need for cancer education to improve knowledge in the rural public and the develop education programmes targeted especially at the old, men, and those who had not cancer screening examination should be considered to plan.

• Journal of agricultural medicine and community health
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• v.23 no.1
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• pp.15-26
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• 1998

To find the prevalence of the Farmer's syndrome and the related factors, we investigated 909 farmers who and older than 30 years and live in Choongju area. The farmers were interviewed individually with a questionnaire from July 18 through 31, 1997. The results are as follows; The prevalence of Farmer's syndrome was 21.0% in male and 45.1% in female. The age prevalence of Farmer's syndrome was higher in thirties and forties than fifties and over sixties in both sex. Farmer's syndrome was significantly higher in low educational status, low income, low family members and more than 20 years of farming group. However, Farmer's syndrome was significantly higher in non smoking and non alcohol intake group, there were no significant differences according to smoking and alcohol intake after stratification by sex. The most frequent symptom in male was lumbago(60.5%), the second was numb limb(49.8%), the third was shoulder stiffness(43.2%) and the fourth was dizziness(31.5%). In female, the most frequent symptom was lumbago(81.3%), the second was numb limb(70.2%), the third was dizziness(62.2%) and the fourth was shoulder stiffness(55.9%). All of these four symptoms are significantly higher in female than in male. With multiple logistic regression for Farmer's syndrome, sex(OR of female=3.3) number of family(OR of <=1.9) and duration of farming(OR of $\geq$2.0 yr=1.5) were turned out to be significant variables.

• Imaging Science in Dentistry
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• v.35 no.2
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• pp.111-114
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• 2005

A 15-year-old patient, who had been diagnosed and treated as Burkitt cell type acute lymphoblastic leukemia (ALL-L3) already, visited our department. He complained of gingival enlargement and loosening teeth 1 month ago. The clinical examination revealed anterior open bite, gingival enlargement, and nontender swelling particularly in molar regions of both jaws. Deep periodontal pockets and severe mobility was shown on most of the teeth. The panoramic radiographs showed severe bone destruction and extrusion of the molars. The contrast enhanced CT showed multiple enhanced mass and bone marrow obliteration in both jaws. Chemotherapy was done and the swelling was subsided at 1 month later. In conclusion, radiologic findings of leukemia with soft tissue mass, known as chloroma or granulocytic sarcoma, mimic those of lymphoma, so blood test may be needed for the final diagnosis.

• Imaging Science in Dentistry
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• v.40 no.4
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• pp.155-158
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• 2010

Digital radiographic systems allow the implementation of a fully digital picture archiving and communication system (PACS), and provide the greater dynamic range of digital detectors with possible reduction of X-ray exposure to the patient. This article reviewed the basic physical principles of digital radiographic imaging system in dental clinics generally. Digital radiography can be divided into computed radiography (CR) and direct radiography (DR). CR systems acquire digital images using phosphor storage plates (PSP) with a separate image readout process. On the other hand, DR systems convert X-rays into electrical charges by means of a direct readout process. DR systems can be further divided into direct and indirect conversion systems depending on the type of X-ray conversion. While a direct conversion requires a photoconductor that converts X-ray photons into electrical charges directly, in an indirect conversion, lightsensitive sensors such as CCD or a flat-panel detector convert visible light, proportional to the incident X-ray energy by a scintillator, into electrical charges. Indirect conversion sensors using CCD or CMOS without lens-coupling are used in intraoral radiography. CR system using PSP is mainly used in extraoral radiographic system and a linear array CCD or CR sensors, in panoramic system. Currently, the digital radiographic system is an important subject in the dental field. Most studies reported that no significant difference in diagnostic performance was found between the digital and conventional systems. To accept advances in technology and utilize benefits provided by the systems, the continuous feedback between doctors and manufacturers is essential.

• Imaging Science in Dentistry
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• v.39 no.2
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• pp.75-79
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• 2009

Purpose: To investigate the incidence and prevalence of C-shaped root canal using computed tomographic images of head and neck in Korean population. Materials and Methods : Regardless of each examination purpose, randomly selected 268 examples which have serial axial computed tomographic images with 8 normal molars in maxilla and mandible were selected and investigated. Defined C-shaped root canal and we could get 82 proper image examples in view of this definition. These were detected and investigated of incidence and prevalence of C-shaped root canal. Results: C-shaped root canals were found in 82 examples among 268 (30.6%) and 147 teeth. They were only found on molar area, and the highest incidence was 37.41% of left mandibular second molars, and the lowest was 2.04% of right maxillary second molars. On prevalence of tooth position, mandibular second molar was the highest, 65% of C-shaped root canal teeth and maxillary second molar was 6% the lowest. Conclusion: 31% of randomly selected CT images no considering check-up reason have C-shaped root canals. The C-shaped root canals of mandibular second molar are found most frequently and they are also detectable on maxilla. On Korean population, C-shaped root canals are one of conditions that have to concern with dental treatment for it appears at a high prevalence relatively. (Korean J Oral Maxillofac Radiol 2009; 39: 75-9)

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.3
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• pp.221-230
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• 2015

Recently, traditional impression has been rapidly replaced by digital impression using intraoral scanning. There are more than 7 types of intraoral scanners available in the dental market. It is difficult to make effective strategic choices due to a lack of standards and guidelines for optimal intraoral scanning devices. So far, little has been reported about evaluating the ergonomic aspect of these scanners. This literature review compares current intraoral scanning systems based on different types of handles and suggests the most comfortable, user-friendly intraoral scanners from an ergonomic standpoint.

• Korean Journal of Social Welfare
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• v.61 no.2
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• pp.61-84
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• 2009

There has been a continuous debate on decentralization of welfare. The proponents of decentralization argue that it will enhance the autonomy of local governments and the efficiency in the provision of service. However, the opponents argue that it will lead to the welfare reduction and the increased inequality among localities. This study attempts to deal with the question, focusing on the evaluation of decentralization reform of Roh Government. The main results are as follows: After the decentralization, local governments has undergone hardships in financing the welfare service, while there is no clear evidence that the local autonomy has enhanced. In respect of fiscal role-sharing, local duties has significantly increased because of the insufficient grants-in-aid for decentralization and inappropriate formula in assessing the grants. In respect of functional role-sharing, the decreased role of central government made it difficult for local governments to provide enough residential institution for the elderly and the disabled. To improve the decentralization reform, deliberate reclassification is needed to decide which item should be transferred to localities. Regarding the characteristic of the projects, social services could be transferred in the long run, while central government should take more responsibilities for the income guarantee and protection for the disadvantaged.