• Biomaterials and Biomechanics in Bioengineering
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• 제3권2호
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• pp.105-114
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• 2016

The purpose of this study is to evaluate the effects of cryopreservation on dental pulp-derived stem cells (DPSC) viability over a period of three years. Dental pulp-derived stem cells were isolated and cultured from thirty-one healthy teeth. DPSC isolates were assessed for doubling-time and baseline viability prior to cryopreservation and were assessed again at three time points; one week (T1), 18 months (T2), and 36 months (T3). DPSC can be grouped based on their observed doubling times; slow (sDT), intermediate (iDT), and rapid (rDT). Viability results demonstrated all three types of DPSC isolates (sDT, iDT and rDT) exhibit time-dependent reductions in viability following cryopreservation, with the greatest reduction observed among sDT-DPSCs and the smallest observed among the rDT-DPSC isolates. Cryopreserved DPSCs demonstrate time-dependent reductions in cellular viability. Although reductions in viability were smallest at the initial time point (T1) and greatest at the final time point (T3), these changes were markedly different among DPSC isolates with similar doubling times (DTs). Furthermore, the analysis of various DPSC biomarkers - including both intracellular and cell surface markers, revealed differential mRNA expression. More specifically, the relative high expression of Sox-2 was only found only among the rDT isolates, which was associated with the smallest reduction in viability over time. The expression of Oct4 and NANOG were also higher among rDT isolates, however, expression was comparatively lower among the sDT isolates that had the highest reduction in cellular viability over the course of this study. These data may suggest that some biomarkers, including Sox-2, Oct4 and NANOG may have some potential for use as biomarkers that may be associated with either higher or lower cellular viability over long-term storage applications although more research will be needed to confirm these findings.

• 한국치위생학회지
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• 제9권1호
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• pp.113-123
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• 2009

This study was undertaken evaluate the general image for dental hygienist. A questionnaire was given to each Dentist, the staff of dental. 65 Dentist, 145 the staff of dental were included in the subjects between Jul. 1 and Oct. 30, 2008. The collected data was analysed by the SPSS Win 12.0/PC using frequency, percentage, mean, standard deviation, chi-square, t-test, ANOVA. The image for the dental hygienist was analyzed by 28 items. As a result of analysis on image of dental hygienist, The Dentist's group and staff's group, both appreciated positive image that explain process of treatment to patient very well, having professional knowledge and experienced skill, carries on an effective and valuable work. give a confidenced to patient. These group also gave negative image in the aspect that the dental hygienist is stressful job, handmaid of Dentist, participate of decided something for dental clinic, having association activities. It is necessary for dental hygienist by oneself development ability through science congress variety major and acquirement new technology, exchange information, interchange activities, and association of dental hygienist should efforts for growing up image through mass media.

• 대한장애인치과학회지
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• 제10권2호
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• pp.78-83
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• 2014

The objective of this study was to confirm the validity of classification of dental disability by measuring the dental treatment time required for disabled patients and identify the disability type that requires more of chair time. As a result of measuring a total of 123 patients who were admitted to the Seoul dental hospital for the disabled on Oct. 2014, I was able to make the following conclusions: 1. For dental counseling and check-up, the chair time did not show significant differences between the different types of disability. 2. For periodontal treatment, restorative treatment, root canal treatment, and surgical treatment, the difference of the chair time for dentally disabled patients was significantly longer than that of non-dentally disabled patients. 3. The difference in the total chair time for prosthetic treatment was statistically insignificant. However, each of the prosthetic treatment steps did show statistically significant differences.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.327-329
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• 2004

치아 매질내에서 전파되는 광신호 해석을 위한 몬테 카를로 수치해석을 National Instrument사의 LabVIEW를 이용하여 개발하였다. 수치해석 결과 치아 조직 내 깊이에 대해 서로 다른 전파 특성을 갖는 두가지 신호를 얻었으며, 검출 신호는 약 60$\mu\textrm{m}$ 이상의 깊이에서 잡음 신호가 특성 신호에 비해 커짐으로 검출이 어려워짐을 알 수 있었다.

• International Journal of Oral Biology
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• 제35권4호
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• pp.209-214
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• 2010

Cells that have endogenous multipotent properties can be used as a starting source for the generation of induced pluripotent cells (iPSC). In addition, small molecules associated with epigenetic reprogramming are also widely used to enhance the multi- or pluripotency of such cells. Skinderived precursor cells (SKPs) are multipotent, sphereforming and embryonic neural crest-related precursor cells. These cells can be isolated from a juvenile or adult mammalian dermis. SKPs are also an efficient starting cell source for reprogramming and the generation of iPSCs because of the high expression levels of Sox2 and Klf4 in these cells as well as their endogenous multipotency. In this study, valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was tested in the generation of iPSCs as a potential enhancer of the reprogramming potential of SKPs. SKPs were isolated from the back skins of 5-6 week old C57BL/6 X DBA/2 F1 mice. After passage 3, the SKPs was treated with 2 mM of VPA and the quantitative real time RT-PCR was performed to quantify the expression of Oct4 and Klf4 (pluripotency specific genes), and Snai2 and Ngfr (neural crest specific genes). The results show that Oct4 and Klf4 expression was decreased by VPA treatment. However, there were no significant changes in neural crest specific gene expression following VPA treatment. Hence, although VPA is one of the most potent of the HDAC inhibitors, it does not enhance the reprogramming of multipotent skin precursor cells in mice.

• 대한치과의사협회지
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• 제53권11호
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• pp.817-843
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• 2015

Korean dentist's new mission was extended in dental practice field since the National Liberation Day of Korea. Modern dentistry development were due to the introduction of american dentistry, the development of Military dentistry, the unified academic activities koreans dental Association and improvement of korean dentist system. Modern dentistry development factors were as follows, First, Seoul National University's professors have been sent for studying abroad since May 1954. Thanks to this advanced system, each dental department established branch academy. Researchers and academic activities were increased in Seoul National University, Second, from January 1954, the military started training program to the korean dentists in the United States, and also the korean dentists were sent to the US Army hospital in korea for practical training courses (On the Job Training) so they could get chances to learn the advanced dentistry. During the korean war, the oral surgery dentists enlarged treatments to the maxillofacial field. Third, korean Dental academy meeting, special lectures and tables clinic from 1947 were contributing to the development of modern dentistry in the transmission of knowledge and skills. Since 1955 "Dentistry(齒學)" with a focus on the translation of foreign literature also developed modern dentistry. Since 1958 the International dental conference could broaden dental knowledge, it also provided opportunities to communicate with the world dentistry. On Oct 11, 1962, revised the Articles of association in Korean Dental academy and korean dental association unified meeting and enhanced the conferences. Improvement of korean dentist system in 1964 unified the dentists as new dentist education. Articles, case reports, review articles and academic meetings of korean dental association from 1946 to 1969 analyzed to demonstrate the development of korean modern dentistry, The titles and lectures were classified according to department and they were organized by topic.

• Environmental Analysis Health and Toxicology
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• 제24권2호
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• pp.149-157
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• 2009

In this study, recognized building-related health symptoms of various workers in dental college hospitals are surveyed and analyzed in order to improve indoor environment at dental college hospitals. We conducted a questionnaire survey for 682 workers in three dental college hospitals located in Seoul from Sep. 20 to Oct. 8, 2004. Most workers at dental hospitals complained about noise, poor ventilation, dusty environment, and air dryness. SBS symptoms score for subjects was 1.43${\pm}$0.74 (often feel) and major symptoms was throat, CNS, eye, and nose symptoms. Recognized Building-related health symptoms are significantly related to tasks, working experience, job-satisfaction, indoor environment recognition index, medical history, used to special material, and number of dental unit chair. Also working places and ventilation are significantly related to the symptom. Based on the results, it can be said that special dental treatment causes undesirable environment such as noise, dust, and bad odor. It is also related to recognized building related health symptoms reported by workers at dental hospitals. So managemental efforts are needed to improve indoor environment which is related by dental treatment.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1245-1252
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• 2022

Induced pluripotent stem cells (iPSCs) can be generated from somatic cells using Oct4, Sox2, Klf4, and c-Myc (OSKM). Small molecules can enhance reprogramming. Licochalcone D (LCD), a flavonoid compound present mainly in the roots of Glycyrrhiza inflata, acts on known signaling pathways involved in transcriptional activity and signal transduction, including the PGC1-α and MAPK families. In this study, we demonstrated that LCD improved reprogramming efficiency. LCD-treated iPSCs (LCD-iPSCs) expressed pluripotency-related genes Oct4, Sox2, Nanog, and Prdm14. Moreover, LCD-iPSCs differentiated into all three germ layers in vitro and formed chimeras. The mesenchymal-to-epithelial transition (MET) is critical for somatic cell reprogramming. We found that the expression levels of mesenchymal genes (Snail2 and Twist) decreased and those of epithelial genes (DSP, Cldn3, Crb3, and Ocln) dramatically increased in OR-MEF (OG2^+/+/ROSA26^+/+) cells treated with LCD for 3 days, indicating that MET effectively occurred in LCD-treated OR-MEF cells. Thus, LCD enhanced the generation of iPSCs from somatic cells by promoting MET at the early stages of reprogramming.

• 한국임상수의학회지
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• 제24권3호
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• pp.295-299
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• 2007

체세포 핵이식을 통한 형질전환 소를 생산 시 초기 수정란 발육 시 발생하는 주요 유전자의 이상 발현을 규명을 목적으로 본 연구를 수행하였다. 형질전환 복제수정란의 낮은 발육능의 원인을 규명하기 위해 하기 위하여 단위 발생란, 체외수정란 및 형질전환 복제수정란에서 초기 배 발육에 중요한 유전자인 IFN-t, Oct4 및 Fgf4유전자의 발현량을 비교 분석하였다. RNA는 각각 10개 수정란에서 추출한 후 reverse-transcription하여 first cDNA를 합성하고 이를 가지고 실시간 중합효수 연쇄반응을 실시하였다. IFN-t유전자의 발현은 형질전환 복제란에서 유의적으로 높게 나왔다 (P<0.05).그러나 Oct4 및 Fgf4 유전자의 경우 형질전환 복제란에서 체외수정란에 비해 유의적으로 낮게 나옴을 확인하였다. 이상의 결과로, 형질전환 복제수정란의 낮은 발육능이 원인이 발육에 중요한 유전자의 이상 발현에 기인된다고 사료된다.

• 치과방사선
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• 제21권2호
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• pp.327-336
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• 1991

The purpose of this study was to evaluate the validity among the clinical, transcraial radiographic and MRI diagnosis in internal derangement of the temporomandibular joint. Fourty two temporomandibular joints were assessed in twenty one patients who visited the dental department of Chonnam National University Hospital with the complaint of temporomandibular disorder from Oct. 1990 to Oct. 1991. The results were as follows: 1. In the clinically symptomatic 29 TMJs, 26 (89.7%) joints reveal disc displacement and 3 (10.3%) joints reveal normal disc position on MRI. The sensitivity of clinical diagnosis was 0.77, and the specificity was 0.63. 2. In the normal 22 TMJs on the trans cranial radiographic finding, 16 (72.7%) joints reveal disc displacement, and 6 (27.3%) joints reveal normal disc position on MRI. In the abnormal 20 TMJs on the transcranial radiographic finding, 18 (90%) joints reveal disc displacement, and 2 (10%) joints reveal normal disc position on MRI. The sensitivity of trans cranial radio- graph was 0.53, and the specificity was 0.75.