• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.149-159
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• 2011

Restoring and replacing teeth with fixed prostheses commonly used in dental practice. Because of improper oral hygiene care and inaccurate laboratory procedure, complication of fixed prostheses was found in the mouth of patient. Although many efforts have been continually made to obtain the data of long term prognosis of fixed prostheses, it was difficult to do it. The purpose of this study was to evaluate the clinical status of fixed prostheses to improve the quality of dental care. In order to assess the clinical status of fixed prostheses, a total of 154 individuals (aged 22-82, 88 women and 66 men loaded with 578 unit of fixed prostheses, and 423 abutments) who visited the Department of Prosthodontics, Pusan National University Hospital, between January 2009 to December 2009 and removed old fixed prostheses were examined. The results of this study were as follows: 1. Length of service of fixed prostheses was $10.3{\pm}05.5$ years (mean), 10.0 years (median). 2. Location of fixed prostheses was found to have statistically significant influence on longevity of fixed prostheses (P<.05). The longevity of fixed prostheses was high in anterior-posterior combination region (mean:13.1, median:13.5) than anterior and posterior region. 3. Longevity of fixed prostheses made of metal was longest (mean:13.3, median:12.3). 4. Number of units in fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 5. Condition of opposing dentition was found to have statistically significant influence on longevity of fixed prostheses (P>.05). The fixed prostheses lasted longest when opposed by complete denture (mean:17.1, median:19.7), removable partial denture, fixed prosthesis and natural dentition trailing behind (P<.05) 6. Periodontal disease (37.5%), dental caries (19.0%), defective margin (18.4%) were frequent complications. In 33.1% of the cases, abutment state after removing fixed prostheses was needed to be extracted.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.359-370
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• 2012

The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. The purpose of this study was to evaluate the clinical status of fixed prostheses to improve the quality of dental care. In order to assess the clinical status of fixed prostheses, a total of 101 individuals (aged 30-89, 66 women and 35 men loaded with 125 fixed prostheses) who treated in the Department of Prosthodontics, Pusan National University Dental Hospital, between January 1990 to December 2005 were examined. The results of this study were as follows: 1. Length of service of fixed prostheses was $9.7{\pm}3.4$ years (mean), 11.1 years (median). 2. Age and sex of patient was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 3. Location of fixed prostheses was found to have statistically significant influence on longevity of fixed prostheses (P<.05). The longevity of fixed prostheses was low in anterio-posterior combination region (median:9.2 years). 4. Longevity of fixed prostheses made of base metal ceramic(median:12.0 years) and noble metal ceramic (median:11.3 years) is long (P<.05). 5. Number of units in fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 6. Condition of opposing dentition was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 7. Dental caries, periapical disease, tooth fracture were frequent complications. In 51.9% of the cases, abutment state after removing fixed prostheses was needed to be extracted.

• Tuberculosis and Respiratory Diseases
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• v.56 no.1
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• pp.29-39
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• 2004

Background : The diagnostic and therapeutic approaches to mediastinal tumors and cysts have changed over the past three decades. This report summarizes our forty-two years of experience with these tumors. Methods : This study retrospectively reviewed 479 patients with primary mediastinal tumors and cysts that were diagnosed and managed over the past 17-year period (1985~2002) and compared them to the report of the previous 25-year result (1960~1985) in Yonsei University College of Medicine, Severance Hospital in Seoul, Korea. Results : During the 17 years, there were 479 cases of pathologically proven mediastinal tumors and cysts. Thymoma (38.2%) was the most common mediastinal tumor and has increased noticeably during recent years. The gender ratio showed a male predominance (1.3:1) and the age distributions were even over all the age groups. The most common sites of the tumor and the proportion(28.6%) of malignant tumors were the same as that previously reported. A diagnosis of a tumor in asymptomatic patients was possible in 174 cases (36.3%), which was higher that reported previously. The diagnostic yield of a fine needle aspiration biopsy was 68.6% in the total tumors and 80.9% in the malignant tumors. A surgical resection was the most frequently chosen treatment modality and was performed in 405 cases (84.6%). The complete resection rate was 91.1%, which is higher than the previous result of 78.8%. Conclusion : These results showed that the prevalence of mediastinal tumors and cysts, particularly thymoma, increased. A fine needle aspiration biopsy was a valuable preoperative differential diagnostic method for malignant tumors. The surgical and complete resection rate increased remarkably possibly due to the better applicable chest CT scans, the more frequent health check-up provided by the regular health promotion program for all people as a health insurance policy, and the improved diagnostic techniques in the pathologic, radiological, and clinical fields.

• Applied Microscopy
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• v.37 no.2
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• pp.83-91
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• 2007

The present study examined the epidermal changes of adhesive disks which occur during attachment in Parthenocissus tricuspidata using scanning and transmission electron microscopy. Several adhesive disks, each covered with a bract, develop from the shoot apical meristem during early development. In the initial stage, the adhesive disks are club-shaped and their upper and lower epidermis are indistinguishable. However, in the actively growing stage, they become spherical and both epidermis are clearly differentiated into the adventitious roots. Prior to wall attachment, the adhesive disks exhibit adaxial convex and abaxial concave shapes, and electron-dense substances are abundant in the vacuoles of epidermal cells. The peripheral area of the adhesive disk is adhered first to the wall surface, while the central area is drawn inward in a vacuum-like state during attachment. As the attachment progresses and the electron-dense substances continue to discharge, the upper and lower epidermis rapidly undergo deterioration and the disks shrink considerably. At this stage, structural changes of the lower epidermis occur much faster than in the upper one. The discharged substance is accumulated on the wall surface, and this aids the attachment of adhesive disks on the wall for long periods. In this manner, the shape and structure of the adhesive disk epidermis change drastically from initial growth to the mature stage. Further, the role of electron-dense substance and shrinkage of the disk during attachment has been discussed in Parthenocissus tricuspidata.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.879-887
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• 2019

The purpose of this study is to establish a physiological injection protocol according to body weight, in order to minimize amount of contrast medium and optimize contrast enhancement in pediatric patients performing thoracic CT examinations. The 80 pediatric patients under the age of 10 were studied. Intravenous contrast material containing 300 mgI/ml was used. The group A injected with a capacity of 1.5 times its weight, and groups B, C and D added 5 to 15 ml of normal saline with a 10% decrease in each. The physiologic model which can be calculated by weight about amount of injection of contrast medium and normal saline, flow rate and delay time were applied. To assess image quality, measured average HU value and SNR of superior vena cava, pulmonary artery, ascending and descending aorta, right and left atrium, right and left ventricle. CT numbers of subclavian vein and superior vena cava were compared to identify the effects of reducing artifacts due to normal saline. Comparing SNR according to the contrast medium injection protocol, significant differences were found in superior vena cava and pulmonary artery, descending aorta, right and left ventricle, and CT numbers showed significant differences in all organs. In particular, B group with a 10% decrease in contrast medium and an additional injection of saline showed a low degree of contrast enhancement in groups with a decrease of more than 20%. In addition, the group injected with normal saline greatly reduced contrast enhancement of subclavian vein and superior vena cava, and the beam hardening artifact by contrast medium was significantly attenuated. In conclusion, the application of physiological protocol for injection of contrast medium in pediatric thoracic CT examinations was able to reduce artifacts by contrast medium, prevent unnecessary use of contrast medium and improve the effect of contrast enhancement.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1114-1121
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• 2018

Purpose: We report the clinical outcomes of patients undergoing additional widening of the limbal incision to prevent disease recurrence after conjunctivo-limbal autograft combined with pterygial excision. Methods: We retrospectively compared 95 eyes with primary and 12 eyes with recurrent pterygia randomized to treatment via two surgical methods: conjunctivo-limbal autograft alone and combined with widening of the limbal incision to allow for pterygial removal. We widened the limbal incisions by 1 mm on both the superior and inferior limbal margins and removed the pterygia. The outcomes were compared between 39 eyes undergoing conjunctivo-limbal autograft alone and 68 eyes undergoing conjunctivo-limbal autograft with widening of the limbal incision. Results: The mean overall postoperative follow-up period was $29.6{\pm}10.5months$ and conjunctivo-limbal autograft alone group was $27.4{\pm}11.5months$, combined with widening of the limbal incision group was $30.7{\pm}9.7months$. Six pterygia (15.4%; four primary and two recurrent) developed in those undergoing conjunctivo-limbal autograft alone and two (2.9%; one primary and one recurrent) in those undergoing additional widening of the limbal incision; the recurrence rate differed significantly between the two groups (p < 0.05). In the group treated with conjunctivo-limbal autograft alone, the mean time to development of a new primary pterygium was $6.3{\pm}3.4months$ and that to development of a recurrent pterygium $4.3{\pm}2.5months$; the respective values for the group undergoing additional widening of the limbal incision were $12.1{\pm}2.6$ and $8.4{\pm}4.6months$; the recurrence rates differed significantly (p < 0.05). Conclusions: Conjunctivo-limbal autograft with additional widening of the limbal incision used to treat both new primary and recurrent pterygia was more effective in terms of reducing pterygial recurrence than conjunctivo-limbal aAutograft alone.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.17-25
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• 2018

Purpose : To compare the radiation doses of prostate cancer patients according to changes in abdominal body shape and energy during Volumetric modulated arc therapy(VMAT). Materials and Methods : Seven patients with prostate cancer were enrolled in this study. VMAT treatment plan was established at 6, 10, and 15 MV while changing from -2.0 cm to 2 cm by 0.5 cm. Conformal index(CI), homogeneous index(HI), $D_{max}$, $D_{95%}$, $D_{50%}$ and $D_{2%}$ of PTV were examined in order to evaluate the change of dose in the target organ according to body shape change. Normal organ of the femoral head, rectum and bladder was analyzed to evaluate dose changes. Results : The dose of $D_{max}$ 6 MV in PTV increased to 107.2 % in 1.0 cm body shape reduction, and 10 MV and 15 MV dose increased to 107.1 % and 107.0 % in 1.5 cm body reduction, respectively. The dose of $D_{50%}$ 6 MV in PTV decreased to 99.64 % in 1.0 cm body shape increase, and in 10 MV and 15 MV dose decreased to 99.79 % and 99.97 % in 1.5 cm body increase, respectively. In 2.0 cm body type increase, the dose was decreased to 99.30 % and 99.52 %, respectively. Doses for rectum and bladder gradually increased with decreasing weight, and dose decreased with decreasing weight. 6 MV, and $V_{70Gy}$ at 10 MV increased from 11.50 % to 12.76 % when the external shape decreased by 2.0 cm. The bladder $V_{70Gy}$ also increased from 14.0 % to 15.2 %. It was also shown that the dose increased as the body weight decreased in the femoral head. Conclusion : In the treatment of VMAT, dose distribution can be changed according to the change of abdominal shape. SSD and CBCT were used to decrease the body shape by more than 1cm or more than 1.0 cm at 6 MV and the body shape by more than 1.5 cm or more than 1.5 cm at 10 MV or 15 MV. It is considered that a new treatment plan should be established through re-simulation.

• Journal of agricultural medicine and community health
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• v.44 no.1
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• pp.11-27
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• 2019

Dementia is major epidemic disease of the 21st century in the world. Dementia is one of the major issues in public health globally. Also in Korea, the estimated prevalence of dementia was 8.7%(0.47 million) in 2010, the number will reach the 1 million mark in 2024, it will become a 15.1%(2.71 million) by 2050. Among Koreans aged 65 or older, 725,000 are estimated to be suffering from dementia in 2017. Against dementia, Korea developed three National Dementia Plans in 2008, 2012, and 2016. The 1st plan was came into effect in 2008 and focused on prevention, early diagnostic, development and coordination of infrastructures and management, and improving awareness. The 2nd plan was launched in 2012, addressed the same priorities but had a stronger focus on supporting family members. In 2012 the Dementia Management Act established a statutory basis for organization of the National Dementia Plans. Under the Dementia Management Act, the government is required to produce a comprehensive plan for dementia every 5 years. The Act also orders that the government should register the dementia patients and collect statistics on epidemiology and the management of the dementia conditions. The Dementia Management Act of Korea required the operation of the National Institute of Dementia and Metropolitan/Provincial Dementia Centers to make and carry out dementia management plans throughout the nation. The Act also mandate to establish Dementia Counselling Centers in every public health center and the National Dementia Helpline. The 3rd National Dementia Plan of 2016 aims to build a dementia friendly community to ensure people with dementia and their carer live well. This plan focus on community-based prevention and management of dementia, convenient and safe diagnosis, treatment, and care for people with dementia, the reduction of the care burden for family care-givers of people with dementia, and support for dementia research through research, statistics and technology. In 2017, Moon's government will introduce the "National Dementia Responsibility System," which guarantees most of the burden caused by dementia. This plan include that the introduction of a ceiling on self-pay for dementia diseases, expansion of the application of dementia care standards through alleviating the support criteria for long-term care insurance for mild dementia, expansion of dementia support centers, expansion of national and public dementia care facilities. In the meantime, Korea has accomplished many accomplishments by establishing many measures related to dementia and promoting related projects in a short time, but there are still many challenges.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.137-144
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• 2021

Purpose : The usability of X-Jaw split VMAT was evaluated by comparative analysis of the dose distribution between the treatment plan divided by X-Jaw and Full field VMAT treatment plan in left breast cancer treatment including supraclavicular lymph nodes. Materials and Methods : 10 patients with left breast cancer, including supraclavicular lymph nodes, were simulated using vacuum cushion, and 2 Full field Arc VMAT and 4 X-Jaw split Arc VMAT were planned The treatment plan was designed to include more than 95% of the Planning Target Volume (PTV) and to be minimally irradiated in the surrounding Organ at risk (OAR). Dose analysis of PTV and OAR was performed through dose volume histogram (DVH). Results : The Full field VMAT treatment plan and the X-Jaw split VMAT treatment plan of 10 patients were expressed as average values and compared. The difference between the two treatment plans was not large, with a Conformity index (CI) of 1.05±0.04, 1.04±0.03, and a Homogeneity index (HI) of 1.07±0.008, 1.07±0.009. For OAR, V5 in the left lung is 56.1±6.50%, 50.4±6.30%, and V20 is 20.0±4.15%, 13.52±3.61%. Compared to Full field VMAT, V5 decreased by 10.0% V20 by 32.6% in X-Jaw split VMAT. The V30 of the heart is 3.68±1.85%, 2.23±1.52%, and the Mean dose is 8.93±1.65 Gy, 7.67±1.52 Gy. In the X-Jaw split VMAT, V30 decreased by 39.3% and the Mean dose decreased by 14.1%. The left lung and heart, which are normal tissues, were found to have a statistical significance of that p-value is less than 0.05. Conclusion : In the case of left breast cancer treatment, which includes Supraclavicular lymph nodes with a large PTV volume and a length of X Jaw of 15 cm or more, the X-Jaw split VMAT shows improved dose distribution, which can reduce radiation dose of OAR such as lungs and heart, while maintaining similar PTV coverage with HI and CI equivalent to Full field VMAT. It is thought to be effective in reducing radiation complications.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.827-833
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• 2023

CT(Computed Tomography) contrast agents are commonly used in general hospitals and university hospitals when taking radiographic examinations. The CT contrast medium contains a mixture of a substance called "Iodine", which absorbs radiation energy and makes it appear white in the CT image, further improving the image quality. In addition, the CT contrast agent, which moves like blood in the blood vessels, clearly differentiates it from muscle and water, so CT contrast agents are widely used in hospitals. These CT contrast agents absorb X-rays, but in order to absorb X-rays, they must have a high density or a high radiation absorption coefficient. Since the CT contrast agent is injected into the blood vessels, if the density is high, the blood vessels are strained and the patient is in shock. For this reason, it is necessary to match the density similar to that of water and always pay attention to side effects. In addition, the amount of CT contrast medium is adjusted according to the patient's body shape, and the remaining contrast medium is discarded. However, This study tried to find out the idea of recycling it as a radiation shielding material. Since the CT contrast medium has a high radiation absorption coefficient at a density similar to that of water, the amount to absorb radiation is adjusted, the amount of contrast medium and the amount of water are adjusted, and the amount of radiation absorbed is determined by mixing with water. In addition, a study was conducted to find out the result of the difference in radiation absorption in various ways by comparing the radiation quality coefficient and absorption coefficient with other substances or materials in an environmentally friendly method harmless to the human body by mixing CT contrast medium and water.