Comparison of measurements from digital cephalometric radiographs and 3D MDCT-synthetized cephalometric radiographs and the effect of head position

Purpose : To investigate the reproducibilities and compare the measurements in digital and MDCT-synthesized cephalometric radiograph, and to investigate the effect of head position on the measurement during imaging with MDCT. Materials and Methods : Twenty-two dry skulls (combined with mandible) were used in this study. Conventional digital cephalometric radiograph was taken in standard position, and MDCT was taken in standard position and two rotated position (10°left rotation and 10°right tilting). MDCT data were imported in OnDemand® and lateral cephalometric radiograph were synthesized from 3D virtual models. Two types of rotated MDCT data were synthesized with default mode and with corrected mode using both ear rods. For all six images, sixteen angular and eleven linear measurements were made in V-Ceph® three times. Reproducibility of measurements was assessed using repeated measures ANOVA and ICC. Linear and angular measurements were compared between digital and five MDCTsynthesized images by Student t-test. Results : All measurements in six types of cephalometric radiograph were not statistically different under ICC examination. Measurements were not different between digital and MDCT-synthesized images (P> .05). Measurements in MDCT-synthesized image in 10°left rotation or 10°right tilting position showed possibility of difference from digital image in some measurements, and possibility of improvement via realignment of head position using both ear rods. Conclusion : MDCT-synthesized cephalometric radiograph can substitute conventional cephalometric radiograph. The error on head position during imaging with MDCT have possibility that can produce measurement errors with MDCT-synthesized image, and these position error can be corrected by realignment of the head position using both ear rods. (Korean J Oral Maxillofac Radiol 2009; 39 : 133-47

Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

Purpose : The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. Materials and Methods : We devised a patient-specific stent for patient-to-image registration and navigation. Threedimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. Results : The accuracy over 8 anatomical landmarks showed an overall mean of 0.56±0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. Conclusion : The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites. (Korean J Oral Maxillofac Radiol 2009; 39 : 149-56)grant of the Korea healthcare technology R & D Project Ministry for Health. Welfare & Family Affairs. Republic of Korea(A08-4491-AL2023-08N1-00030B)

Basic concept and application of image-guided implant

OAIID:RECH_ACHV_DSTSH_NO:A201700345RECH_ACHV_FG:RR00200003ADJUST_YN:EMP_ID:A076356CITE_RATE:DEPT_NM:치의학과EMAIL:[email protected]_YN:CONFIRM:

방사선을 조사한 성장기 백서의 두개안면부 조직에서의 apoptosis

Thesis (doctoral)--서울대학교 대학원 :치의학과 구강악안면방사선학전공,2000.Docto

Problems of Fictionality in the Fictions of Lee Cheongjun

학위논문(석사)--서울대학교 대학원 :인문대학 국어국문학과,2019. 8. 손유경.This study begins with the question, "Why did Lee Cheongjun write fiction?" which has not been explained actively until now. This question concerns the 'effect' of fiction. For Lee, fiction is a form of self-statement, and fictionality is a major factor intervening in the context of a statement. Specifically, fictionality works like an alibi that conceals the identity of a messenger or the true meaning of a message. However, the problem that I want to pay attention to is the fact that such a concept of fictionality works in a very contradictory way in Lee's works. Fictionality can make the empirical truth of the narrator very unclear, or interfere with the reader's intervention. This study focused on problems around the concept of fictionality in Lee's fictions and tried to contextualize such contradictions. In the second chapter, I examined the author's autobiographical and social background, which led to his perception of fictionality. And I also looked at how the author's request that the novel should be read as 'fiction' is specifically realized in the work. The reason why the fictionality is highlighted in Lee's works is that fictionality can act like an alibi, which increases the degree of freedom of statements and triggers the reader's intervention. In particular, Lee's early works show an experimental attempt to 'un-naturalize' reading novels. Such works reveal that the existence of a narrator and the proper name of a character are signposts of fictionality. In the third chapter, I looked at works in which characters perform self-examination through fiction and studied the pros and cons of such fictional self-statements. In Lee's works, the alienated appear as subjects to tell their stories, and it is also characterized by the fact that their statements are made in a fictionalized context. These features result in a very opaque portrayal of the characters, but on the other hand, it is the factor that imprints the otherness of the other. However, there is also a problem that fictionality is used in the characters' self-statements as a way to cover up the truth. This could ultimately make the truth indistinguishable from falsehood. In the fourth chapter, I explored how fictionality (mal)functions in Lee's fictional self-statements. In a series of Namdosaram, he wanted to depict the transcendence of 'pansori' to find a linguistic model that can communicate his personal history transparently. In Festival, Lee uses fictionality as a device to examine his self-statement. For example, he not only surfaced the author's intention but also appeared fictional characters censoring his self-statements. However, as a result, Lee's fiction has a problem in that he just used such characters as proof of the authenticity of his statement and hastily settled the conflict between the characters by inserting a fairy tale.본 연구는 그동안의 연구사에서 왜 쓰는가라는 작가의 문제틀에 주목하는 가운데, 정작 적극적으로 해명되지 않았던 왜 소설인가라는 물음으로부터 출발한다. 이 물음은 소설의 본질을 묻거나, 소설의 태도를 표명하는 방식으로 다루어질 때 필연적으로 한계에 봉착하게 된다. 따라서 본고는 이청준의 글쓰기에서 소설이라는 형식이 발생시키는 효과가 무엇인지 우선 질문하고자 했다. 기본적으로 소설은 자기진술을 위한 형식이라는 작가의 입장을 고려할 때, 자기진술이 소설의 틀로써 수행된다는 점은 독자로 하여금 그런 진술을 허구화된 맥락에서 수용하게끔 만드는 조건이라고 할 수 있다. 요컨대 소설의 효과는 메신저의 정체나 메시지의 진의를 불투명하게 만드는 것이며, 본고는 이를 허구성의 알리바이(fictional alibi)라 명명하였다. 본 연구에서 본격적으로 규명하고자 했던 문제는 그러한 허구성의 개념이 이청준의 소설쓰기에서 매우 모순적인 방식으로 작동한다는 사실에 있다. 특히 소설은 허구적이며 작가-독자가 상상의 공간에서 만나 함께 진실을 모색하도록 만든다는 이청준의 소설론은 도리어 소설의 허구성이라는 논리적 토대에 의하여 이율배반에 직면한다. 실제로 허구화된 자기진술에서 화자의 경험적 진실은 매우 불투명하게 서사화되는 양상을 보인다. 그러므로 독자는 결국 진술된 사건의 진실이 무엇인지 알 수 없거나, 아니면 해석의 여지를 압도하는 화자의 서술로 인해 진실 규명의 과정에 개입할 수 없게 된다. 본 연구는 이와 같은 이율배반의 발생과정과 그 근거를 재맥락화하고자, 이청준의 소설(론)에서 허구성이 (오)작동하는 방식에 주목하였다. 먼저 2장에서는 이청준의 작품이 근대소설(novel)의 위기를 돌파하는 해법의 하나로서, 소설을 다름 아닌 픽션(fiction)으로 읽을 것을 요청한다는 사실을 확인하였다. 소설의 허구성에 대한 작가의 (재)인식은 소설가의 경제적 불안정, 표현의 부자유라는 일종의 선고유예적 상황에서 비롯된다. 그러한 상황에서 이청준의 소설(론)이 허구성을 강조하는 이유는, 소설의 허구성은 곧 알리바이처럼 작동하며 진술의 자유도를 높이고 독자의 개입을 촉발시킬 수 있는 요인이기 때문이다. 특히 이청준의 초기 단편에서는 소설읽기를 비자연화하고자 하는 작가의 인식을 발견할 수 있다. 구체적으로 설명자면 이청준의 소설은 서술자를 텍스트에 각인된 존재가 아니라 작가의 의도를 적극 구현하는 구성적 존재로, (등장인물의) 이름을 인물의 실체성을 환기하는 장치가 아니라 비실재성의 표지로 바라보게 함으로써, 소설을 허구화된 자기진술의 일종이자 비가시적인 삶을 구현하는 양식으로 읽게 만든다. 3장에서는 이청준의 작품에서 등장인물들이 소설을 통해 자기진술을 수행하는 경우를 고찰하며, 소설적 자기진술이라는 모델의 이점과 한계를 함께 살펴보았다. 그의 소설에서는 사회적 타자들이 자신의 이야기를 진술하는 주체로서 등장하고, 또한 그 진술이 허구화된 맥락에서 이루어진다는 특징이 있다. 이러한 특징들은 196,70년대 붐을 일으킨 논픽션 장르에서와 달리 소설 속에서 타자들이 매우 불투명하게 묘사되는 결과를 낳지만, 타자의 타자성 자체를 각인시키는 요인이 되기도 한다. 이는 궁극적으로 독자로 하여금 텍스트 너머 실재하는 타자의 삶을 상상하도록 만드는 효과를 발휘한다. 그러나 다른 한편으로 등장인물의 자기진술에서 허구성은 빈번하게 오작동을 일으킨다. 이청준에게 허구성은 타자성이 음각된 자기진술의 성립을 위한 필요조건이었지만, 한편으로 소설적 진술의 무의식(진실)을 형성함과 동시에 진실을 재은폐하는 방식으로 작동하며, 결국 거짓/진실 사이의 구분이 무의미한 형태의 담론(소문)을 재생산할 가능성이 있다. 마지막으로 4장에서는 작가의 소설적 자기진술이 전면화되며 나타나는 허구성의 문제들을 돌아보았다. 이청준은 언어의 타락을 목도하며 믿을 수 있을 만한 말의 형식을 탐구했던바, 그것은 점차 언어를 투명화하고자 하는 시도로 이어진다. 특히 남도사람 연작에서 그가 소리의 초월성을 형상화하고자 했던 것은 자신의 내력을 투명하게 전달할 수 있는 하나의 언어적 모델을 확보하기 위함이다. 하지만 이청준의 소설에서 소리의 초월성은 인물에 대한 폭력을 통해 구축되는 것일 뿐만 아니라 결국엔 일종의 도그마로서 드러난다는 문제가 있다. 장편 축제에서는 다시 소리에서 소설로 자기진술의 토대를 옮겨, 허구성을 자기진술의 진실성을 검토하기 위한 장치로 활용한다. 예컨대 축제에서는 텍스트의 겹(편지와 작가노트)을 통해 작가적 의도가 표면화되어 있으며, 동시에 주인공의 진술을 검열하는 허구적 인물들이 등장한다. 하지만 결과적으로 이청준은 자기진술의 정당성을 확보하려는 목적 아래 그러한 인물들을 기능적으로 활용할 뿐만 아니라, 동화를 삽입하여 인물들 사이의 갈등을 성급하게 봉합하고 만다. 단편 ｢오마니｣가 암시하는 대로, 이청준은 자기진술의 실질적 내용과 형식이나 다름없던 어머니의 상실을 모성의 신성화를 통해 극복하고자 하는 모습을 보인다. 달리 말해서 이러한 사실은 내력 깊은 이야기라는 이청준의 문학적 모델이 결국 신화적 양식으로 귀착될 수밖에 없었음을 의미한다. 여기서 허구성의 알리바이가 담보했던 이청준 소설의 서사적 활력은 상당부분 감소하는 것처럼 보인다. 하지만 그럼에도 불구하고 이청준이 도달한 한계점이 무의미하다고만 할 수는 없다. 이청준의 소설(론)은 픽션문학이 안고 있는 가능성과 문제성을 동시에 체현하는 일종의 문학적 보고서이기 때문이다. 소설의 허구성은 진술의 자유를 위한 것이자 동시에 진실을 은폐하기 위한 것이기도 했으며, 이청준의 글쓰기는 바로 그 역설을 안고 불안하게 이어져왔다. 이청준의 소설이 보여준 실패는 결국 말의 자유와 언어의 진실 사이의 부조화라고 할 수 있지만, 한편으로 이청준은 그 (불)가능한 종합의 방법론을 모색하기 위한 텍스트로서 다시 읽히고 해체될 필요가 있다.1. 서론 1 1.1. 문제제기 및 연구사 검토 1 1.2. 연구의 시각 15 2. 형식적 리얼리즘을 비자연화하기 24 2.1. 내력 있음이라는 이야기의 조건 혹은 억압 24 2.2. 선고 유예된 소설가와 픽션 읽기의 시민성 29 2.3. 노블의 서술자 및 고유명사의 탈법정화 39 3. 소설적 자기진술의 성취와 패러독스 56 3.1. 논픽션 비판과 상상되는 타자성 56 3.2. 허구성의 오작동: 무의식의 생성과 은폐의 반복 69 4. 다시 씌어지는 자서전과 해체하는 영화 82 4.1. 투명한 언어에의 실험: 소리의 (탈)신비화 82 4.2. 자기검열로서의 픽션과 신화로의 귀착 94 5. 결론 109 ※ 참고문헌 113 ■ Abstract 121Maste

인공적 인접면 치아우식증의 구내방사선사진과 디지탈 영상의 진단능 평가

학위논문(석사)--서울대학교 대학원 :치의학과 구강악안면방사선학 전공,1995.Maste

Morphometric Study of the Irradiation Effect on the Cartilage Formation in the Rat Mandibular Condyle

Purpose: This study was undertaken to quantitatively estimate the degree of the damage and recovery of the irradiated rat condylar cartilage using the Image Analyzer. Materials and Methods: Experimental animals were 16 male rats of the Sprague-Dawley strain at the age of 20 day irradiated with the dose of 10 Gy in their head and neck region. Four rats were sacrificed at the each of the following time intervals - 1, 4, 7 and 14 days, respectively. The same number of control group animals were sacrificed at the each age of 21. 24, 27 and 34 days, respectively. The specimens were stained with 0.5％ toluidine blue and examined with light microscope. The condylar cartilage was divided into 4 zones; fibrous zone, proliferating zone, upper hypertrophic zone, and lower hypertrophic zone. And then, the proliferating zone was subdivided into 2 layers - upper and lower layer, and upper and lower hypertrophic zone were subdivided into three layers, respectively - upper, middle and lower layer. With the aid of Image Analyzer, morphometric analysis was performed. The thickness, the numerical density of cells, the cell area density, the extracellular matrix area density, the mean area of single cell, the mean area of extracellular matrix per single cell were measured and analysed. Results: In the experimental group, the thickness of the fibrous zone was slightly increased and that of the proliferating zone and the upper and the lower hypertrophic zone was markedly decreased. With time, the thickness of the fibrous zone was gradually increased and that of the proliferating zone and the upper and the lower hypertrophic zone was steadily in the decreased state. The numerical density of cells of the proliferating zone was increased on post-irradiated 1 day, but decreased after post-irradiated 4 day, and that of the upper hypertrophic zone was decreased. The numerical density of cells of the lower hypertrophic zone was decreased in the early stage and then was decreased or not significantly different from that of the control group with time. In the experimental group, the cell area density of the fibrous zone and the proliferating zone was decreased in the early stage and then gradually increased or not significantly different from that of the control group with time. The cell area density of the upper and the lower hypertrophic zone was varied with time. The extracellular matrix area density value were totally opposite to the cell area density values: The mean area of single cell of the fibrous zone and the proliferating zone was .decreased on post-irradiated 1 day, and increased after post-irradiated 4 day. The mean area of single cell of the upper hypertrophic zone was varied with each layer and time. In the experimental group, the mean area of extracellular matrix per single cell of the fibrous zone was not significantly different with control group, and that of the proliferating zone was decreased on post-irradiated 1 day, and increased after post-irradiated 4 day. The mean area of extracellular matrix per single cell of the lower hypertrophic zone was increased in the early stage. and that of upper hypertrophic zone was varied with each layer and time. Conclusion: The condylar cartilages of rats were affected by irradiation, but the changes were vaned with each layer and time. By morphometric analysis. the changes of the cells of the condylar cartilage of irradiated rat could be calculated quantitatively.이 논문은 1998년 서울대학교병원 치과대학 임상연구비지원에 의해 이루어진 것임

The Effect of Irradiation and Epidermal Growth Factor on Cell Cycle and Apoptosis Induction in Human Epithelial Tumor Cell Lines

Purpose : This study was aimed to evaluate the cell cycle arrest and apoptosis induction after irradiation and epidermal growth factor (EGF) treatment in three human epithelial tumor cell lines (A431, Siha, KB). Materials and Methods: Single irradiation of 2, 5 and 10 Gy was done on three cell lines with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. Also, EGF of 10 ng/ml was added immediately after 10 Gy irradiation. Cell growth was evaluated by counting the living cell number using a hemocytometer at 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Cell cycle arrest and apoptosis induction were assayed with the flow cytometry at 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Results : Growth of irradiated three cell lines were inhibited in proportion to radiation dose. EGF treatment after irradiation showed various results according to cell lines. On all cell lines, G2 arrest was detected after 8 hours and maximized after 12 hours or 1 day. Amount of G2 arrest was positively dose dependent. However, EGF showed no significant change on G2 arrest. G2 arrest was recovered with time at 2 Gy and 5 Gy irradiation. However, at 10 Gy irradiation, G2 arrest was continued. Apoptosis was detected at 10 Gy irradiation. On EGF treated group after irradiation, A431 and Siha cell lines showed slightly increased apoptosis but there was no statistically significant difference. KB cell line showed no marked change of apoptosis induction. Conclusion : Irradiation effects on cell cycle arrest and apoptosis induction in three human epithelial tumor cell lines, however epidermal growth factor doesn't effect on.본 연구는 교육부 1999년도 BK21의생명분야의 지원으로 이루어짐

치과용 실시간 원격판독시스템의 개발 및 평가

Teleinterpretation is the electronic: transmission of radiographic images from one geographic location to another for the purpose of diagnosis. The real time teleinterpretation system that makes use of the internet was developed and evaluated. In addition, the required time, for using the system was investigated to evaluate the usefulness during the dental works in dental clinic or hospital. The program was designed for the users or general practitioner and the interpreters, or the experts of oral and maxillofacial radiology. The users and interpreters could use the system after downloading the program for teleinterpretation in the homepage using the internee Several functions were developed for the purpose of the usefulness. The average required time of users from sending the digital image to receiving the result of interpretation of interpreters was 60.5 seconds when one user send an image independently; and 5 minutes 54 seconds when 10 users send an image simultaneously. So it was thought to be an adequate real time teleinterpretation system for dentistry

Leiomyosarcoma of the Mandible : Report of a Case

Leiomyosarcoma is extremely rare in the oral cavity and especially in the mandible. At first. the case of this report was diagnosed as odontogenic fibroma but after approximately 3.5 years. it was diagnosed as leiomyosarcoma. Conventional radiograph of the first time showed an ill-defined radiolucent lesion in the mandible. After local recurrence. CT images showed a large irregular soft tissue mass with some necrotic areas. These findings were not specific for leiomyosarcoma, but they suggested that this lesion was a recurrent soft tissue sarcoma. Histopathological examinations using H & E staining, immunohistochemical staining and Masson's trichrome staining confirmed this case as leiomyosarcoma. Deciding its malignancy or benignancy, defining the tumor extent and its relationship to the surrounding anatomic structures, and evaluating the distant metastasis are more important roles of radiographic examination than finding out the name of disease