• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.641-644
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• 2002

얼굴 특징점 추출은 현재 많은 연구가 활발히 진행되고 있는 분야로 보안, 인식 등 다양한 응용분야를 갖는다. 본 논문에서는 PC 카메라 및 주민등록증에 있는 사진을 스캔하여 얼굴 특징점을 정확하고 빠른 계산 시간안에 찾을 수 있는 새로운 방법을 제시한다. RGB 색공간을 YUV로 변환하여 Y성분을 히스토그램 균등화 시켜 휘도에 관계없이 얼굴 피부색을 추출한 후 YUV의 V성분을 변형한 V'성분을 이용하여 얼굴의 특징점을 찾는 방법이다. 실험결과 주민등록증 사진과 PC 카메라에서 입력 받은 얼굴 영상이 오류 없이 추출됨이 관찰되었다.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.107-119
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• 2005

Temporomandibular joint arthritides is divided into osteoarthritis, osteoarthrosis and polyarthritis. Because the signs, symptoms and radiographical features of osteoarthritis and osteoarthrosis are similar without arthralgia, diffenential diagnosis is difficult. Also non-radiographically change in early Osteoarthritis leads to misdiagnose. Planar bone scan and SPECT are useful to detect bone change early. This study was carried out in order to make diagnostic criteria of planar bone scan and SPECT. Three hundred and four temporomandibular joints were examined with clinical examination, computerized tomograph, planar bone scan, and SPECT. The obtained results were as follows. 1. If temporomandibular joint simple uptake ratio of patient in twenties is over 1.397%, it's condition may be osteoarthritis. And simple uptake ratio over in thirties-fourties may mean osteoarthritis. 2. It may mean osteoarthritis of temporomandibular joint that the number of coronal and transverse SPECT frame with hot spot is over four. 3. Destructive stage may goes on, if simple uptake ratio is over 1.370% in tweenties and over 1.104% in thirties-fourties. 4. If the number of coronal SPECT frame with hot spot is over four, temporomandibular joint may be on destructive stage in tweenties, thirties-fourties. And if the number of transverse SPECT frame with hot spot is over three, it may be on destructive stage in all ages. 5. When patient complains subjective arthralgia and palpation arthralgia, bone change may be more active than each arthralgia. 6. Osteoarthritis may progress gradually worse in 4.5 anamnesis. And then it may be stable gradually and turn to osteoarthrosis.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.497-503
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• 2018

The purpose of this study was to investigate the degree of image degradation and the improvement of image quality caused by the density difference between the orthodontic filling material and the surrounding anatomical structure during the examination of the facial CT by quantitative and qualitative analysis. The teeth were scanned using 64-MDCT (Discovery 750 HD, GE HEALTH CARE, Milwaukee, USA). The teeth were scanned and compared according to tube voltage, silicone application, and MAR application. As a result, 10.36% CT value decreased at 140 kVp and 5.81% decrease at the application of silicon material. As a result of the qualitative evaluation, it was evaluated that 7 of the 10 observers and 3 of the acceptors were applied to the MAR algorithm. Therefore, it is possible to reduce the unnecessary burden on the radiation exposure dose as well as to reduce the loss of image data by reducing the high density artifacts, as well as the inspection parameters used in the current clinical application and various algorithms that can reduce the high density artifacts. It can be expected to provide a lot of image information.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.316-327
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• 2023

In the case of fully edentulous patients with severe alveolar bone resorption, the consideration of 'All-on-X' implant-supported fixed prosthesis after placing four or more implants in the anterior maxilla is possible. Recent advancements in digital dentistry have enabled systematic and predictable treatment in all phases, including diagnosis, surgery, and prosthesis fabrication. By incorporating digital dentistry techniques such as digital complete denture, implant surgical guides, facial scanning into the conventional restoration process, it is possible to reduce the complexity of the prosthesis fabrication and effectively achieve the transition from provisional prosthesis to definitive prosthesis in terms of both aesthetics and function.

• Archives of Craniofacial Surgery
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• v.14 no.1
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• pp.11-15
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• 2013

Background: In cleft lip patients, the necessity of a thorough preoperative analysis of facial deformities before reconstruction is unquestioned. The surgical plan of cleft lip patient is based on the information gained from our preoperative anthropometric evaluation. A variety of commercially available three-dimensional (3D) surface imaging systems are currently introduced to us in plastic surgery for these use. However, few studies have been published on the soft tissue morphology of unrepaired cleft infants described by these 3D surface imaging systems. Methods: The purpose of this study is to determine the accuracy of facial anthropometric measurements obtained through digital 3D photogrammetry and to compare with direct anthropometry for measurement in unilateral cleft lip patients. We compared our patients with three measurements of dimension made on both sides: heminasal width, labial height, and transverse lip length. Results: The preoperative measurements were not significantly different in both side of labial height and left side of heminasal width. Statistically significant differences were found on both side of transverse lip length and right side of heminasal width. Although the half of preoperative measurements were significantly different, trends of results showed average results were comparable. Conclusion: This is the first study in Korea to simultaneously compare digital 3D photogrammetry with traditional direct anthropometry in unilateral cleft lip patients. We desire this study could contribute the methodological choice of the many researchers for proper surgical planning in cleft lip reconstruction field.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.383-386
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• 2008

Osteomyelitis is considered an inflammatory condition of bone that usually begins as an infection of the medullary cavity and quickly extends to periosteum of the area. Early acute osteomyelitis of the mandible is usually characterized by deep, intense pain, high intermittent fever, paresthesia or anesthesia of the lower lip and a clearly identifiable cause. If the disease is not controlled or inadequately treated after onset, acute osteomyelitis progresses to a chronic form. The diagnosis of mandibular osteomyelitis rests on processing for identification of microbiologic isolates and on imaging studies to determine the extent of disease. Mandibular osteomyelitis often is associated with involvement of the masticator space and can exhibit symtoms similar to temporomandibular disorder including orofacial pain and limited mouth opening. Advanced imaging modalities can be helpful in obtaining a proper diagnosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.658-665
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• 2000

Purpose : The present study was carried out to determine the diagnostic usefulness of bone scan for evaluating jaw bone extension of oral cancer. Materials and Methods : Medical records, preoperative bone scans, computerized tomographic (CT) scans, conventional radiographs, and findings of histopathologic sections of twenty patients who had been treated for oral malignant tumors by a resection of mandible and soft tissue at Chonnam University Hospital from January, 1994 to September, 1999 were analyzed. Results : In 13 cases which showed histopathologically positive, preoperative bone scans were positive in 12 (92.3%) and false negative in 1 (7.7%). Preoperative CT scans were positive in 9 (69.2%) and false negative in 4 (30.8%) of the 13 cases. Preoperative conventional radiographs were positive in 8 (61.5%) and false negative in 5 (38.5%) of the 13 cases. In 7 cases showing negative histopathologic findings, 1 (14.3%) was in CT scans and 2 (28.6%) were false positive in preoperative conventional radiographs. Conclusion : These results suggest that bone scan is more sensitive and reliable method for evaluating jaw bone extension of oral cancer than conventional radiographs or CT scans.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.373-378
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• 1993

Although osteochondroma is not rare in the axial skeleton and long bones, it is very rare in the jaw. It is a benign chondroma within which partial endochondral ossification occurs. There are two types, the central one and the peripheral one. Peripheral type is more common than central one in the jaw, but it is not frequent. Especially it is rare at the mandibular condyle. When it occurred at the mandibular condyle, it is generally located at the lateral portion of the condyle. In that case, facial asymmetry with occlusal change is the characteristic clinical feature. But it is similar to condylar hyperplasia so that misdiagnosis can sometimes occur. The differential point is as follows: Hyperplasia generally appears as a generalized enlargement of the condylar process with a normal cortical thickness, but osteochondroma usually appears as a focal growth or mass. We report a very rare case of peripheral osteochondroma at the mandibular condyle in a 27-year- old male patient who visited DKUDH with a chief complaint of the facial asymmetry.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.336-343
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• 2010

Coronary artery CT angiography has short scanning length, the exposure dose is high. Therefore, it is required to study on the organ dose when using MDCT. We compared the differences between the absorbed dose and effective dose in the major organs assessing the absorbed dose in the major organs by 16-MDCT and 64-MDCT in the subjects with coronary artery CT angiography, the same protocol by 16-MDCT and 64-MDCT. As a result, the great orders of absorbed dose when conducting coronary artery CT angiography had been shown as heart, stomach, liver, pancreas, kidney, spleen, large intestine, lung, small intestine, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.538{\pm}0.026(Mean{\pm}SD,\;p<0.05)mGy{\sim}71.316{\pm}4.316mGy$ in 16-MDCT, and heart, stomach, pancreas, spleen, liver, kidney, small intestine, large intestine, lung, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.87{\pm}0.01mGy{\sim}115.26{\pm}1.59mGy$ in 64-MDCT, demonstrating some different distributions. The exposed doses to the patient per one time scanning with coronary artery CT angiography were $71.316{\pm}4.316mGy$ in 16-MDCT as the absorbed dose based on the heart and $115.26{\pm}1.59mGy$ in 64-MDCT. The effective doses were 7.41 mSv and 12.11 mSv in 16 and 64-MDCT, respectively. Taking into account the results of brain CT with 2.8 mSv that has comparatively large scanning length and size, facial CT 0.8 mSv, chest CT 5.7 mSv, pelvic CT 7.2 mSv, and abdominal and pelvic CT 14.4 mSv, it is very high considering the scanning length of 13 cm limited to the heart for the scanning range.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.