• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.38-43
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• 1999

Tooth transposition is the phenomenon in which two teeth in the dental arch are exchanged. The tooth most frequently involved in transposition is the permanent maxillary canine, especially with the first premolar. The etiology of transposition is still an enigma. Interchange of tooth germs, migration during eruption, genetic factor, local pathologic factors may be suggested as possible etiologic factors. There are three main options for treatment, which are the extraction of one of the transposed teeth, the alignment in the transposed position, the orthodontic movement of the teeth to their correct positions. If complete transposition occurred especially in mandible, alignment of teeth in the transposed position followed by occlusal reduction and esthetic restoration is usually recommended. The presented two-case report will describe the maxillary canine to the first premolar and to lateral incisor transposition with associated peg lateralis and retained primary canines. Although alignment the transposed teeth in original position is ideal treatment, it companies many complication as root resorption, alveolar bone destruction, gingival deheisence, etc. Therefore the treatment procedures in these case was relative cost-benefit effective method to both clinician and patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.2
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• pp.145-148
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• 2010

Maxillofacial injuries are less common in children than in adolescents and adults. This lower incidence is a result of the relatively small size of mandible, the resilient nature of the bones, and a relatively protected environment, which distinguish the treatment principles of pediatric mandibular fractures from those of the adult. The bone of child is malleable, so pediatric fractures tend to be less displaced and rarely comminuted. Moreover, high regeneration potential of the wound allows more conservative treatment modalities for the pediatric mandibular fracture. High risk of damaging unerupted tooth bud renders many clinicians to resort to more conservative treatment modality for the reduction of displaced segments. This case report describes two successful treatment cases using the circummandibular wiring which was applicated to the fracture on parasymphysis of mandible. Circummandibular wiring can protect the tooth buds, and there is no need for intermaxillary fixation so that it prevents the possible complications of intermaxillary fixation such as the temporomandibular joint ankylosis and the facial growth disturbances. The acrylic splint was removed after 3 weeks, which showed clinically good union across the fracture line without complications. They showed complete clinical and radiological bone healing with an optimum occlusion.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.358-394
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• 1995

The author studied the actual conditions on the production of dental prosthesis made in laboratories, and also studied interrelationships between dentists and laboratory technicians in both personal and technical aspects. Two hundred-eighty four technicians, work in dental laboratories presently, were surveyed via mail and direct contact during the period from June 1 to June 30 and August 27 to August 28 in 1994 respectively. The obtained results were as follows : 1. Among the respondents, 90.5% we re working in commercial dental laboratories and their laboratories were mainly located in the Seoul area(40.9%, P<0.05). The numbers of employees in these laboratories were less than 10 persons(70.0%, P<0.01), and 75.9% of these laboratories have been in operation less than 15 years. 2. Most laboratory procedures were accomplished according to established disciplines. However, procedures such as die trimming in fixed restorations and the qualifications of the people designing removable partial dentures were not. Other problem areas were boxing of the working cast, the person determining the posterior palatal seal area, selection and arrangement of artificial teeth, occlusion rim correction and laboratory remounting of the processed denture in complete denture restorations. 3. Only half of the requesting dentists could send work authorizations to the laboratories with their work and even so, its contents were quite lacking. Consequently, there must be some standards in writing work authorization. 4. Technicians most desired clean and accurate impressions in fixed and removable dentures, and enough tooth reduction in porcelain fused to metal restorations. 5. For the establishment of better relationships between dentist and dental technician, the respondents desired the establishment of equal footing first(33.5%), and frequent conversations and muture understanding second(25.9%).

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.299-306
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• 2017

In this case report, immediate loading of an implant-supported single-tooth prosthesis through complete digital workflow. A patient presented for restoration of missing a single tooth in the mandibular first molar. The digital impression was made with intraoral scanner and implant was placed using surgical guide pre-fabricated with pre-operative computed tomography (CT) and scan data. After 1 week later, prefabricated customized abutment and provisional restoration were connected for immediate loading. After 8 weeks later, abutment level impression was taken by intraoral scanner. At 3 months later from implant installation, monolithic zirconia crown were fabricated. This clinical report presents satisfying result in accuracy and patient satisfaction. A completely modeless digital procedure met expectations regarding precision, esthetics, and functionality.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.63-74
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• 2009

Partial or complete prosthesis is needed when teeth are lost due to various kinds of reason. Artificial teeth recover occlusion instead of natural teeth. Artificial teeth are required of esthetics, fragile resistance and abrasive resistance. Artificial tooth is made of acrylic resin or porcelain. Nowadays, acrylic resin artificial teeth are mainly used. Acrylic resin teeth are occluded with natural teeth, gold alloy, Ni-Cr alloy or porcelain etc. Acrylic resin teeth have similar translucency, gloss of natural teeth. And it has good chemical bond with denture base material, but it has low wear resistance. The aim of this study is to compare wear resistance among several denture teeth(Endura, SR-orthosit-PE, Planustar) and between artificial resin denture teeth and opposing 3 restorative materials(gold, Ni-Cr alloy, porcelain). Wear tests were conducted with a rotating wear testing apparatus(pin-on-disk type wear tester) under conditions of rpm 180, 75 minutes and constant loading of 50N. The upper part was the cusp of maxillary first molar and the lower part was a disk type restorative materials. To make similar oral environment, water was supplied continually. The acrylic resin teeth wear was determined by weighing the cusp each 5 minutes during 75 minutes test. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows: 1. Wear rates of acrylic resin teeth opposing to the restorative materials were high in order of Porcelain, Gold, Ni-Cr alloy (p<.05). 2. Wear resistance rate opposing to the Porcelain disk, was shown in order of Endura, SR-orthosit-PE, Planustar. The wear rate of opposing to porcelain disk was above two times more than that of other groups (p<.05). 3. Wear resistance rates opposing to the Gold, Ni-Cr alloy disk, was shown in order of Endura, SR-orthosit-PE, Planustar (p<.05). 4. A degree of the surface hardness is directly proportional to the degree of wear resistance. There are statistically significant differences between each groups (p<.05).

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.4
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• pp.254-261
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• 2005

Dental statistics for Koreans are far from complete and the majority of previous researches have adopted techniques such as radiological analysis and sectioning of teeth for morphological information, which are time-consuming, less accurate and destructive. Thus, a new nondestructive method is necessary to get precise dental standardization data for Koreans. For the above purpose, each of the first premolars was scanned by a micro-CT (SkyScan, Belgium) with a resolution of $21.31{\mu}m$ at an interval of 0.022mm along the plane horizontally parallel to an occlusion plane. Internal and external morphological sections were measured and compared to the values in the average tooth size table for permanent teeth presented by G. V Black.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1063-1068
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• 2000

Objectives : To determine the contribution of cranial magnetic resonance angiography(MRA) for the evaluation of patients with ischemic cerebrovascular accident. Methods : Magnetic resonance image(MRI) and MRA studies performed on 34 patients with ischemic stroke were retrospectively reviewed with the clinical records. Results : There were 9 transient ischemic attacks and 25 completed strokes in our series. Twenty-three of 34 MRA examinations(68%) were positive for stenosis or occlusion. The distribution of stenotic or occlusive vascular lesions were correlated with the location of infarction in 22 of the 23 positive cases(96%). MRA provided additional information not obtained from the MRI in 19 cases(56%). Conclusions : Vascular lesions demonstrated on intracranial MRA show a high correlation with infarct distribution. MRA provided information adjunctive to conventional MRI in a majority of cases. We conclude that MRA is an important noninvasive component of the complete evaluation of ischemic stroke.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.257-261
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• 2011

Objective : Successful coil embolization of anterior communicating (A-com) artery aneurysms requires good visualization and understanding of the entire H complex. Bilateral carotid angiography may optimize anatomical understanding and visualization of the H complex. We therefore assessed the efficacy of simultaneous bilateral internal carotid angiography during coil embolization for A-com artery aneurysms. Methods : Of the 153 patients with intracranial saccular aneurysms who underwent embolization between July 2008 and December 2009, 12 had A-com artery aneurysms and were embolized under bilateral carotid angiography. Patients were evaluated angiographically, immediately and 6 months (n=11) after embolization, using a 3-point scale (complete, residual neck, residual aneurysm). The safety, performance and efficacy of this approach were retrospectively evaluated. Results: In all patients, bilateral internal carotid artery angiography provided more detailed anatomical information and understanding around the A-com artery, and, in complex situations, it allowed for more effective coil embolization through bilateral routes to the A-com artery. Angiography immediately after embolization showed occlusion of 11 of the 12 (92%) aneurysms, with none of these 11 showing evidence of recanalization at 6 months. Conclusion : These findings indicate that simultaneous bilateral carotid angiography during coil embolization of selected complex A-com artery aneurysms provided improved anatomical understanding, and resulted in more effective and safer procedures than typical unilateral angiography.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.397-418
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• 1994

Microvascular surgery has been widely used in the clinical field of replantation and reconstructive surgery. Since the last 20 years, microsurgical techniques and instruments have been rapidly developed and the success rate is remarkably increased. But thrombotic occlusion of vessels remains the major reason for clinical failure. The change of vessel wall is the most important factor in thrombus formation. If we can reduce the traumatic changes in the vessel walls during surgery, the success rate can be markedly increased. For this study, femoral arteries and veins of 36 Sprague-Dawley rats with average weights of 300gm were used. The author observed the histological changes and healing process in the anastomostic site after 1 hour, 24 hours, 1, 2, 3 and 4 weeks under light microscopy and scanning electron microscopy. The results were as follows : 1. The patency rate was 100% in femoral arteries and 85% in femoral vein. 2. At the early stages after microvascular anastomosis, the loss of endothelial cell in the vessel walls was observed in the wide area including anastomotic site. In scanning electron microscopic finding the anastomotic site was covered with much fibrin, many red blood cells and some platelets. 3. At 1st week, new endothelial cells were formed toward anastomotic site and at 3rd week, the anastomotic site was completely covered by new endothelial cells. At 4th week, the complete endothelialization over the threads was observed. 4. The media extended from the anastomotic site toward the end of the specimen. At later stages, the extent of media necrosis was markedly decreased. But the media necrosis of anastomotic site was not regenerated till 4th week. 5. Intimal hyperplasia appeared at 1st week and increased till 4th week. The layer consisted of endothelialization the most luminal layers and smooth muscle in the deeper layers. But in veins, the response was less pronounced than in arteries. 6. Foreign body granuloma remained during 4 weeks and aneurysm was observed at 3rd week in artery. In aneurismal wall, media necrosis, loss of elastic lamina and intimal hyperplasia were seen.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.1
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• pp.55-62
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• 2017

Overdenture using dental implants could improve the problems of conventional complete denture function which are pain during mastication, insufficient retention and stability. Locator attachment used widely for implant-retained overdenture has advantages that it needs the smallest vertical space and also its nylon male cap allows personalized retention for each case. However its retention force decreases rapidly with function rather than the bar and ball attachment. So, implant fixture should be positioned as parallel as possible.