• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.307-318
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• 2001

Objective : Surgical experiences of pseudoaneurysms such as traumatic, mycotic and ill-defined unknown causes of aneurysms are rare. The authors have studied the results of surgical management from such cases in our series. Patients and Method : In the last 17 years, 1320 patients with cerebrovascular aneurysms were managed surgically. Among these, 16 patients showed the pseudoaneurysms. The authors analyzed retrospectively the clinical characteristics, treatment methods, management outcomes and problems in the managements. Results : There were 6 patients with traumatic aneurysm, 4 mycotic aneurysms and 6 ill-defined unknown causes of aneurysm. The sites of traumatic aneurysms were cavernous portion of the internal carotid artery(n=3), distal portion of the anterior cerebral artery (n=2) and vertebral artery(VA : n=1). Good outcomes in 5 cases could be obtained by extracranial - intracranial bypass followed by parent vessel occlusion or resection of aneurysm followed by re-anastomosis of parent vessel. The sites of mycotic aneurysm were peripheral portions of middle cerebral artery(MCA : n=3) and posterior cerebral artery(PCA : n=1). The outcomes of the patients with a mycotic aneurysm were relatively poor. It was partially due to the development of new aneurysm after treatment in one. The sites of ill-defined unknown causes of aneurysm were extracranial carotid artery(n=3), V2 portion of the VA(n=1), peripheral portion of the PCA (n=1) and MCA(n=1). Good outcome in all cases could be obtained by resection of aneurysm with or without saphenous vein graft. Conclusion : For the treatments of cerebrovascular pseudoaneurysm, combinations of aggressive medical, endovascular and surgical managements seem mandatory. Insertion of stent for a extracranial carotid artery aneurysm and coiling for a peripheral mycotic aneurysm can be option in future.

• Journal of Korean Neurosurgical Society
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• v.48 no.3
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• pp.207-212
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• 2010

Objective : To assess the feasibility, safety, and effectiveness of the balloon-assisted technique with HyperForm balloon in the endovascular treatment of wide-necked intracranial aneurysms. Methods : A total of 34 patients with 34 wide-necked intracranial aneurysms were treated with endovascular coil embolization using balloon-assisted technique with Hyperform balloon. Twenty-nine aneurysms (85.3%) were located in the anterior circulation. The group of patients was comprised of 16 men and 18 women, aged 33 to 72 years (mean : 60.6 years). The size of aneurysms was in the range of 2.0 to 22.0 mm (mean 5.5 mm) and one of neck was 2.0 to 11.9 mm (mean 3.8 mm). The dome to neck ratio was ranged from 0.83 to 1.43 (1.15). Sixteen patients were treated for unruptured aneurysms and the remaining 18 presented with a subarachnoid hemorrhage. Results : In the 34 aneurysms treated by the remodeling technique with HyperForm balloon, immediate angiographic results consisted of total occlusion in 31 cases (91.2%) and partial occlusion in three cases (8.8%). There were five procedure-related complications (14.7%), including two coil protrusions and three thromboembolisms; Except one patient, all were successfully resolved without permanent neurologic deficit. No new bleeding occurred during the follow-up. Twenty patients (59%) underwent angiographic follow-up from 2 to 33 months (mean 9.2 months) after treatment. Focal recanalization with coil compaction of the neck portion was observed in 5 cases (25%). Only one case showed major recanalization and underwent stent-assisted coil embolization. Conclusion : The balloon-assisted technique with Hyperform balloon is a feasible, safe, and effective endovascular treatment of wide-necked cerebral aneurysms.

• The korean journal of orthodontics
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• v.46 no.6
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• pp.379-385
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• 2016

Objective: Forced eruption has been proposed for the reconstruction of deficient bone and soft tissue. The aim of this study was to examine the changes in the alveolar ridge width and the vertical levels of the interproximal bone and papilla following forced eruption. Methods: Patients whose hopeless maxillary anterior teeth were expected to undergo severe bone resorption and soft tissue recession upon extraction were recruited. In addition, patients whose maxillary anterior teeth required forced eruption for restoration due to tooth fracture or dental caries were included. Before and after forced eruption, the interproximal bone height was measured by radiographic analysis, and changes in the alveolar ridge width and the interproximal papilla height were measured with an acrylic stent. Results: This prospective study demonstrated that the levels of the interproximal alveolar bone and papilla were significantly increased by 1.36 mm and 1.09 mm, respectively, in the vertical direction. However, the alveolar ridge width was significantly reduced by an average of 0.67 mm in the buccolingual direction. The changes in the level of the interproximal alveolar bone and papilla were positively correlated. Conclusions: Although the levels of the interproximal bone and papilla were significantly increased, the alveolar ridge width was significantly decreased following forced eruption. There was a modest positive and significant correlation between the changes in the height of the interproximal alveolar bone and the papilla. Based on our findings, modification of vertical forced eruption should be considered when augmentation of the alveolar ridge width is required.

• Korean Journal of Computational Design and Engineering
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• v.17 no.4
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• pp.253-261
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• 2012

In order to make dental implant surgery successful, it is important to perform proper planning for dental implant placement. In this paper, we propose a decent approach to dental implant placement planning based on geometric processing of 3D models of jawbones, a nerve curve and neighboring teeth around a missing tooth. Basically, the minimum enclosing cylinders of the neighboring teeth around the missing tooth are properly used to determine the position and direction of the implant placement. The position is computed according to the radii of the cylinders and the center points of their top faces. The direction is computed by the weighted average of the axes of the cylinders. For a cylinder whose axis passes the position along the direction, its largest radius and longest length are estimated such that it does not interfere with the neighboring teeth and the nerve curve, and they are used to select the size and type of an implant fixture. From the geometric and spatial information of the jawbones, the teeth and the fixture, we can construct the 3D model of a surgical guide stent which is crucial to perform the drilling operation with ease and accuracy. We have shown the validity of the proposed approach by performing the finite element analysis of the influence of implant placement on bone stress distribution. Adopted in 3D simulation of dental implant placement, the approach can be used to provide dental students with good educational contents. It is also expected that, with further work, the approach can be used as a useful tool to plan for dental implant surgery.

• Journal of Radiation Protection and Research
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• v.27 no.2
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• pp.111-120
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• 2002

A reference scenario of vault safety case prepared by the IAEA for the near-surface disposal facility of low-and informed]ate-level radioactive wastes is assessed with the MASCOT program. The appropriate conceptual models for the MASCOT implementation is developed. An assessment of groundwater pathway through a drinking well as a geosphere-biosphere interface is performed first. then biosphere pathway is analysed to estimate the radiological consequences of the disposed radionuclides based on compartment modeling approach. The validity of conceptual modeling for the reference scenario is investigated where possible comparing to the results generated by the other assessment. The result of this study shows that the typical conceptual model for groundwater pathway represented by the compartment model ran be satisfactorily used for safety assessment of the entire disposal system in a cons]stent way. It is also shown that safety assessment of a disposal facility considering complex and various pathways would be possible by the MASCOT program.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.239-244
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• 2003

The common errors in preoperative treatment plan for the orthognathic surgery can be occurred during cast impression, cast mounting procedure with face-bow transfer, surgical stent fabrication, and so on. One of the most common errors exists during mounting process of the model on the articulator. Accurate mounting of dental casts to articulator should be achieved by transferring the 3-dimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used for transfer this relationship to articulator, usually by relating the face-bow to a plane of reference of maxillary cast. The purpose of this study is evaluation of the accuracy of face-bow transferring of maxillary model to the articulator. The maxillary casts of thirty patients for orthognathic surgery were mounted on articulator with an face-bow instrument. The relationship of occlusal plane angle to Frankfort horizontal plane relations were compared the cephalogram with the cast-mounted articulator. As a result of this study, the significant difference between the maxillary occlusal planes angle in the cephalogram and articulator were found. The results were followed, 1. The mean occlusal plane angle in cast-mounted articulator was $13.5^{\circ}\;(SD{\pm}5.4)$. 2. The mean occlusal plane angle in cephalogram was $10.4^{\circ}\;(SD{\pm}4.3)$. 3. The mean difference of occlusal plane angle between cast-mounted articulator and cephalogram was $3.3^{\circ}\;(SD{\pm}4.6)$. According to the result, we should suggest that the occlusal plane angle to Frankfort plane in cast-mounted articulator is more steeper than that of cephalogram. And then, maxillofacial surgeon should try to get a more predictable result by suggesting the proper correction method and mounting the cast accurately.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.397-406
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• 1995

The purpose of this study was to evaluate the changes of interproximal bone density by means of videodensitometer and to examine the clinical applicability of videodentitometer to assess the periodontal disease activity.Twelve interproximal sites, with periodontal pockets deeper than 5mm and vertical loss of bone on standard dental radiograph, were treated by subgingival curettage. The papilla bleeding index, the plaque index, the degree of mobility, the depth of pockets, and the level of attachment were measured. Standardized reproducible radiographs were taken by using the occlusal stent with parallelling film holder. The density of the interdental bone was measured on the radiographs by a videodensitometer at three levels: the most 'superficial' level; the 'deep' level, arbitrarily 1.5mm below: and the 'apical' level, where no bony changes were to be expected. The clinical parameter and the radiographical change were measured at initial, and 1 month, 3 months, and 6 months after treatment.The results were as follows :1. The papilla bleeding index and the degree of mobility decreased significantly until 3 months after subgingival curettage and showed the Same level in the remaining experimental periods. 2. The pocket depth mainly decreased due to the gingival recession until 1 month after treatment, but to the attachment gain after 1 month. 3. The density of the interdental bone did not show a significance increase until 1 month after treatment, but showed a steady increase throughout the 6 months of observation. 4. The close relationships were shown between the decrease in pocket depth and the gain of attachment and the improvement of bone density at 6 months after treatment.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.126-133
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• 2018

The development of cone beam computerized tomography (CBCT) allows three-dimensional analysis of the patient's anatomy. The surgical guide is a combination of CBCT, computer-aided design/computer-aided manufacturing (CAD/CAM) and implant diagnostics software, which allows well planned prostheses design and ideal implant placement. Guided surgery minimizes possible anatomical damage and allows for more reproducible treatment planning. In this case, the operation time was shortened by using a surgical guide for multiple implants placement in a fully edentulous patient. Immediate loading were performed more easily using preliminary preparation of provisional prosthesis. The patient was satisfied with improved esthetics and chewing function.

• The Journal of Advanced Prosthodontics
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• v.10 no.4
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• pp.279-285
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• 2018

PURPOSE. The aim of this clinical study was to assess the accuracy of the implants placed using a universal digital surgical guide. MATERIALS AND METHODS. Among 17 patients, 28 posterior implants were included in this study. The digital image of the soft tissue acquired from cast scan and hard tissue from CBCT have been superimposed and planned the location, length, diameter of the implant fixture. Then digital surgical guides were created using 3D printer. Each of angle deviations, coronal, apical, depth deviations of planned and actually placed implants were calculated using CBCT scans and casts. To compare implant positioning errors by CBCT scans and plaster casts, data were analyzed with independent samples t-test. RESULTS. The results of the implant positioning errors calculated by CBCT and casts were as follows. The means for CBCT analyses were: angle deviation: $4.74{\pm}2.06^{\circ}$, coronal deviation: $1.37{\pm}0.80mm$, and apical deviation: $1.77{\pm}0.86mm$. The means for cast analyses were: angle deviation: $2.43{\pm}1.13^{\circ}$, coronal deviation: $0.82{\pm}0.44mm$, apical deviation: $1.19{\pm}0.46mm$, and depth deviation: $0.03{\pm}0.65mm$. There were statistically significant differences between the deviations of CBCT scans and cast. CONCLUSION. The model analysis showed lower deviation value comparing the CBCT analysis. The angle and length deviation value of the universal digital guide stent were accepted clinically.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1539-1541
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• 2012

Cholangitis is relatively uncommon but associated mortality is high due to the predisposition in people with underlying disease. For this recognition of contributing risk factors is necessary. Therefore, the present descriptive-analytical cross-sectional survey was designed to determine contributing risk factors for post-ERCP cholangitis in patients with pancreatic cancer. From 2005 to 2010, 110 consecutive cases of pancreatic cancer attending to a tertiary referral centre (Taleghani Hospital), Tehran, Iran were recruited. The patients all underwent stenting via endoscopic retrograde cholangiopancreatography (ERCP). On univariate analysis, a metallic stent type (95% confidence interval (CI) 1.025-11.34, P=0.037), having no jaundice (1.44-2.22, P=0.009), having no pain (1.32-1.91, P=0.026), a history of prior ERCP (1.16-10.37, P=0.020), and having a proximal biliary stone (1.002-5.93, P=0.046) were related to cholangitis. However on multivariate analysis, none of these factors were found to be contributing risk factors. Cholangitis is avoidable with adequate biliary drainage. Because success rates are higher and complication rates lower for endoscopists performing large volumes of ERCP, performance of the procedure should be concentrated as much as possible in institutions with endoscopists having adequate experience. Patients with a high risk for complications may be best served by referral to an advanced center.