• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1135-1146
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• 2013

In this paper, we proposed a new algorithm for individual tooth region segmentation on tooth color images. The proposed algorithm used oral cavity model based on structural feature of tooth and new boundary of watershed algorithm. First, the gray scale image is obtained with emphasized tooth regions from the color images and unnecessary regions are removed on tooth images. Next, the image enhancement of tooth images is implemented using the proposed oral cavity model, and the individual tooth regions are segmented by watershed algorithm on the enhanced images. Boundary and seeds necessary to watershed algorithm are applied boundary of binary image using minimum thresholding and region maximum value. In order to evaluate performance of proposed algorithm, we conduct experiment to compare conventional algorithm with proposed algorithm. As a result of experiment, we confirmed that the proposed algorithm is more improved detection ratio than conventional algorithm at molar regions and the tooth region detection performance is improved by preventing overlap detection on oral cavity.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.421-426
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• 2000

조직공학은 결손된 조직의 구조 및 기능을 신속히 수복할 수 있도록 적절한 생체소재, 세포, 활성인자 세가지 구성요소를 적절히 조합하는 것이다. 이렇게 하므로써 결손된 조직을 대체할 수 있는 세포에 대한 부착, 이동, 증식, 분화조건을 최적상태로 만들어 주는 것이다. 이러한 관점에서 치아임플랜트의 조직 공학적 적용은 다음 몇가지 관점을 고려할 수 있다. 첫째, 인공치아 임플랜트도 넓은 의미에서 그 자체로서 조직공학의 범주에 들어간다고 할 수 있다. 따라서 결손된 치아의 구조 및 기능을 신속히 회복시킬 수 있도록 조직공학적인 관점에서 검토할 수 있다. 생체소재는 표면에너지의 관점에서, 세포는 골모세표와 섬유모세포관점에서, 활성인자는 세포분화 촉진인자의 관점을 고려할 수 있다. 둘째, 치아임플랜트의 기능회복 촉진을 위한 조직공학기법을 부가적으로 적용하는 것이다. 임플랜트와 생체조직사이에 기능성 조직을 신속히 형성시키므로써 임플랜트의 기능회복을 촉진하는 적절한 생체소재, 세포, 활성인자를 적절히 이용하는 정통 조직공학기법을 적용하는 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.231-234
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• 2002

This paper considers a system related to biometrics which can control entrance and exit based on pattern and feature of a tooth. It is aimed at research and development of a controling entrance and exit system connected advanced image understanding technique using a tooth recognition that treats a tooth of simple and fixed structure. We think that the system is applied(or utilized) as pre-step or assistance means of face recognition and expect that the system achieves greatly effective results.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.7 no.1
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• pp.6-17
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• 1998

Tooth bleaching was being done more than 100 years ago, but the standard for vital tooth bleaching for the last quarter century has been the use of hydrogen peroxide with heat or with a combination of heat and light. The major disadvantages of this process are high cost, unpredictability of results, and patient discomfort. In March, 1989, the dental world was introduced to a new vital tooth bleaching process by Haywood and Heymann in their article "Nightguard vital bleaching(NGVB)." Interestingly enough, this simple technique could have been developed years ago if we had known about the chemical effects of carbamide peroxide on tooth structure. NGVB has created a resurgence in the area of bleaching, primarily because of its relative ease of application, the safety of the materials used, low cost, and the high percentage of successful treatments. This article was to explain simply about all around NGVB(etiology of stains, bleaching chemicals and mechanisms, bleaching effectiveness, side effect, documentation, indications, treatment therapy, laboratory procedure, case reports)

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.664-676
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• 1996

테트라싸이클린에 의한 치아 변색은 심미성을 고려한 임상 치료시 커다란 난제로 남아 있다. 본 연구는 백서 치아에 테트라싸이클린을 주입하여 야기되는 색상과 구조적인 변화도를 측정하여 향후 연구에 기초자료를 제공하기 위해 시행되었다. 24 마리의 백서를 각기 8 마리씩 3 군으로 분류하여 대조군은 정상적인 사육을 식염수군은 TC군과 동량의 식염수를 주사하였으며 TC군은 12 ml에 용해시킨 60 mg의 테트라싸이클린을 복강내로 2 주간 주입하였다. 최종 주입후 1 주간 정상 사육한 다음 cervical dislocation법에 의해 희생시켜 시편을 채득한 후 각 치아를 횡단하여 실물현미경과 FlexCam을 이용하여 컴퓨터에 영상을 저장한 다음 색 변화량을 Adobe Photoshop으로 측정하였으며 구조변화는 주사전자 현미경을 이용하였다. 치아색 변화량의 유의성 검정은 ANOVA와 Scheffe test를 이용하였으며 본 실험 결과는 다음과 같다. 1. 각 군의 $a^*$ 수치는 대조군 -6.12 (1.18), 식염수군 -8.00 (1.33), TC군 -18.56 (2.52)로 나타났으며 $b^*$ 수치는 대조군 1.12 (2.13), 식염수군 1.62 (1.45), TC군 28.67 (5.18)을 보였다. 즉 테트라싸이클린에 의해 $a^*$와 $b^*$의 수치가 유의성있게 (p<0.01) 초록색과 노란색 방향으로 변화하였다. 2. 테트라싸이클린에 의해 치경부 법랑질 외면이 검게 변색되었으며 울퉁불퉁한 양태로 변화되었다. 그러나 법랑소주의 형태, 방향등은 차이를 보이지 않았다. 3. 각 군간 상아세관의 수, 방향, 크기등이 차이가 없었다. 치수측에서의 관찰결과 대조군과 식염수군에서는 상아세관들의 입구가 크고 명확하게 보인 반면 TC군에서는 입구가 좁고 부분적으로 막힌 양태도 관찰되었다.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.401-407
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• 2008

The most common type of orofacial pain is toothache. However, many other types of pain which derived from nonodontogenic problems can mimic toothache. Nonodontogenic toothache is heterotopic pain that the site of pain is not in the same location of the source of pain. This differs from primary pain, in which the site of pain is the actual site which the pain originates. Heterotopic pain can be alleviated by direct treatment toward the source of pain. The common sources of nonodontogenic toothache include neuropathic pain, sinus pain, Myofascial pain, neurovascular pain and even cardiac pain and psychogenic pain. Thus, clinicians should have a thorough knowledge about causes of nonodontogenic toothache, and through pain history and examination of dental and nondental structures are needed. This case report is about some cases of nonodontogenic toothache, and it also emphasizes essential considerations for proper differential diagnosis and appropriate treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.97-102
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• 2012

Odontoma is a mixed tumor formed by the overgrowth of ectodermal epithelial cells and mesodermal cells. It arises during normal tooth development and only grows to a certain level. It is not a true neoplasm and therefore it is considered as hamartomas. Odontomas are classified into compound and complex types based on morphology. Compound odontoma is commonly found in the anterior region of the maxilla, and has a radiopaque lesion that resembles small teeth. Usually, odontoma is treated by conservative surgical removal and there is little probability of recurrence. This paper describes three cases of compound odontoma diagnosed in children with 1 year of follow-up. These case reports present patients having eruption disturbance of primary and permanent teeth due to the presence of compound odontoma. In order to induce spontaneous eruption, conservative surgical removal was performed showing favorable results.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.140-145
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• 2016

Excessive occlusal wear causes loss of tooth structure, occlusal plane disharmony, impaired function and esthetic problems. Although the decrease of occlusal vertical dimension may be compensated by the growth of alveolar bone and tooth eruption, minimal increase of occlusal vertical dimension may be required for esthetics and retention of prosthesis. In this case, a 44-year-old male patient visited Seoul National University Dental Hospital with chief complaint of severe tooth wear and shade disharmony. Based on assessment of diagnostic wax-up, 3 mm increase of occlusal vertical dimension was determined. Removable occlusal splint and interim prosthesis was used to ascertain patient's comfort and adaptation. After the adaptation period, definitive prosthesis fabricated with full-contour monolithic zirconia were delivered and the patient was recommended to wear a nightguard device for prosthesis protection. This report presents a case of full mouth rehabilitation with the elevation of patient's occlusal vertical height, resulting in satisfactory esthetics and functions.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.2
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• pp.121-129
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• 2020

From the point of view of oral rehabilitation, the treatment of extensive tooth wear requires a prosthetic approach. Physiological tooth wear is considered as a normal process and generally does not require treatment, but excessive tooth wear causes problems like inadequate occlusion and esthetics. Changes of occlusal vertical dimension should be made through accurate diagnosis and analysis. Also, the patient's adaptation to the changed occlusal vertical dimension should be assessed over time. This case was a 60-year-old male patient who complained of a decrease in chewing function and esthetics due to severe tooth wear. Full-mouth rehabilitation was performed with a tooth supported fixed prosthesis. An occlusal stabilization splint and provisional restoration were used to evaluate the adaptation to increased occlusal vertical dimension and induce a stable centric relation position. After that, monolithic zirconia prosthesis was delivered. We report this as a satisfactory functional recovery and esthetics.

• Applied Microscopy
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• v.40 no.3
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• pp.147-154
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• 2010

The aim of this study is to determine microstructure, chemical composition and crystal structure of hydroxyapatite for mouth teeth using optical microscopy and electron microscopy as well as electron probe micro-analysis (EPMA). Enamel, a protective cover to the teeth, consisted of rods oriented in regular and had relatively higher crystallinity and Ca component. In contrast, dentin showed a sponge-like microstructure with circular holes which were passages of dentinal tubules, and had higher Mg component than the enamel region due to its higher organic content. Hydroxyapatite crystals appeared as large rods in enamel, but as small needles in dentin. Their electron diffraction patterns were different by their crystallinity as well as by the organic content of the matrix.