• The korean journal of orthodontics
• /
• v.18 no.1 s.25
• /
• pp.79-88
• /
• 1988

The purpose of this study was to investigate the factors which might be related to mandibular third molar eruption and to predict the possibility of whether or not it will be erupted. The material of this study was lateral cephalometric radiograms, pantomograms and dental casts obtained from 70 patients (19 males, 51 females) ranging in age from 18.0 to 32.1 years. They were devided into erupted group and impacted group of mandibular third molars. For the comparison of each group, a total of 20 measurement items were employed and the data were analyzed by means of computer statistical method. As a result of this study, the following conclusion can be made; 1. The longer mandibular body length and narrower mandibular ramus width, the higher eruption tendency of the lower third molar, but the degree of genial angle was not related to mandibular third molar eruption. 2. The lower percentage of posterior mandibular body height to anterior mandibular body height, the higher eruption tendency of the lower third molar. 3. The total tooth size, including the lower second molar, appeared to be larger in the impacted group than in the erupted group of the lower third molar. 4. The arch length discrepancy of the impacted group was more severe in contrast with the erupted group of the lower third molar.

• Tuberculosis and Respiratory Diseases
• /
• v.78 no.2
• /
• pp.112-119
• /
• 2015

Primary thymic adenocarcinoma is a very rare malignancy of the anterior mediastinum with no standardized treatment. A 36-year-old male patient presented with hoarseness over the past 3 months. A chest computed tomography (CT) scan showed an infiltrative mass to the proximal vessels and aortic arch in left upper mediastinum ($4.1{\times}3.1{\times}5.4cm$). Brain magnetic resonance imaging (MRI) showed focal lesions, suggesting metastasis in the left frontal lobe. A thoracoscopic biopsy of the mediastinal mass confirmed a primary thymic adenocarcinoma forming a glandular structure with atypia of tumor cells. The patient received four cycles of systemic chemotherapy, consisting of etoposide and cisplatin, with concurrent radiotherapy (6,000 cGy/30 fractions) to the mediastinal lesion and the metastatic brain lesion (4,200 cGy/12 fractions). A follow-up chest CT scan and brain MRI showed a decrease in the size of the left upper mediastinal mass and brain lesion. We report a rare case of the primary thymic adenocarcinoma with a literature review.

• Journal of Korean Association for Spatial Structures
• /
• v.19 no.3
• /
• pp.69-76
• /
• 2019

A Beam String Structure (BSS) is a type of hybrid structures, which is composed of upper structural members, lower strings, and struts. Due to the advantages that the pre-tensioned strings elicit pre-caber of the upper structural members, the deflection can be greatly reduced without increasing the structural member size. In this study, a two-way beam string structure is proposed to endure bi-directional loading. The two-way beam string structure consists of two cable parts, namely, sagging and arch-shaped cables. A parametric study is presented aimed at proposing design guide lines of the two-way beam string structures. Numerical finite element analyses through the ABAQUS package were implemented to obtain their behaviors.

• Archives of Plastic Surgery
• /
• v.49 no.6
• /
• pp.755-759
• /
• 2022

Brachial artery aneurysms are rare diseases that may be caused by infection or trauma. We report a case of a 71-year-old man who presented with a mass in his right antecubital fossa that increased in size slowly over time. Three years ago, the patient underwent ascending and total-arch replacement with artificial vessel graft to treat aortic root and ascending aorta aneurysm. Preoperative physical examination of right upper extremity showed a nonpulsatile mass with normal pulse of axillary, brachial, and radial arteries. The mass was removed and brachial artery reconstruction was done initially using saphenous vein graft. Two months later, the patient revisited with recurrent pseudoaneurysm, involving the bifurcation point of brachial artery. Aneurysm was totally resected and the brachial artery was reconstructed by interposition graft using a bifurcated GORE-TEX artificial vessel graft. The patient healed without complication and no recurrence was observed. Artificial vessel graft is an available option for reconstruction, and revascularization of vessel defect after excision of brachial artery aneurysm may involve bifurcation point.

• Journal of Korea Water Resources Association
• /
• v.53 no.1
• /
• pp.29-43
• /
• 2020

The purpose of this study is to propose the design criteria and detailed design model by reviewing the issues related to geometry, formation process, destruction process, hydraulic function, restoration and ecological function of the step-pool from the existing research results, to apply the step-pool sequences to river restoration. Based on the analysis and review results, the design criteria for the structure and size of the step-pool are presented as ratio of the step spacing and the channel width, ratio of the unit step slope and channel slope, and ratio of step height and the particle size. To ensure structural stability of the step, stability analysis method of overturning based on the keystone theory was proposed as a design criterion. As a detailed design concept, a layout model was proposed by applying the imbricating structure of keystones and arch stones to the planar, longitudinal and transverse configurations of the step-pool.

• Journal of Korean Association for Spatial Structures
• /
• v.9 no.3
• /
• pp.75-82
• /
• 2009

This paper investigates the variation of post-buckling behaviours of spatial structures after sizing optimization with linear assumptions. The mathematical programming technique is used to produce the optimum member size of spatial structures against external load. Total weight of structure is considered as the objective function to be minimized and the displacement occurred at loading point and member stresses of structures are used as the constraint functions. The finite difference method is used to calculate the design sensitivity of objective function with respect to design variables. The post-buckling analysis carried out by using the geometrically nonlinear finite element analysis code ISADO-GN. It is found to be that there is a huge difference between the post buckling behaviours of the initial and optimized structures. Therefore, the stability of optimized spatial structures with linear assumption should be throughly checked by appropriate nonlinear analysis techniques. Finally, the present numerical results are provided as benchmark test suite for future study of large spatial structures.

• Restorative Dentistry and Endodontics
• /
• v.28 no.6
• /
• pp.485-490
• /
• 2003

Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.1
• /
• pp.8-14
• /
• 2017

Objective : The purposes of this study were to introduce a superficial temporal artery (STA)-sparing mini-pterional approach for the treatment of cerebral aneurysms and review the surgical results of this approach. Methods : Between June 2010 and December 2015, we performed the STA-sparing mini-pterional approach for 117 patients with 141 unruptured intracranial aneurysms. We analyzed demographic, radiologic, and clinical variables including age, sex, craniotomy size, aneurysm location, height of STA bifurcation, and postoperative complications. Results : The mean age of patients was 58.4 years. The height of STA bifurcation from the superior border of the zygomatic arch was $20.5mm{\pm}10.0$ (standard deviation [SD]). The craniotomy size was $1051.6mm^2{\pm}206.5$ (SD). Aneurysm neck clipping was possible in all cases. Intradural anterior clinoidectomy was performed in four cases. Contralateral approaches to aneurysms were adopted for four cases. Surgery-related complications occurred in two cases. Permanent morbidity occurred in one case. Conclusion : Our STA-sparing mini-pterional approach for surgical treatment of cerebral aneurysms is easy to learn and has the advantages of small incision, STA sparing, and a relatively wide surgical field. It may be a good alternative to the conventional pterional approach for treating cerebral aneurysms.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.30 no.4
• /
• pp.265-277
• /
• 2014

Purpose: The purpose of this study was to investigate the differences of displacement pattern depending on type of sliding jig and application method during maxillary molar distalization with temporary anchorage devices (TADs). Materials and Methods: Maxilla with normal tooth size and arch shape was selected to create a 3-dimensional finite element model, which included the bracket, orthodontic main archwire, removable sliding jig (R-jig). The orthodontic mini-implant anchorage was set 8 mm superiorly from main archwire, buccally between the second premolar and first molar. The base experimental design was Condition 1, which was composed $0.019{\times}0.025$ inch stainless steel (SS) of wire size of R-jig, 200 gm force, un-tied state. And the other designs varied to wire size of R-jig, magnitude of force. The results are as follows. Results: As the wire size of R-jig was increased, the deformation of R-jig was decreased. However, the displacement of second molar wasn't different each other. As the force to second molar was increased, the more displacement of second molar was observed, and the more distal tipping movement, vetical displacement was observed. Conclusion: R-jig can get distal teeth movement in orthodontic treatment without side effects.

• Korean Journal of Cleft Lip And Palate
• /
• v.2 no.1_2
• /
• pp.5-14
• /
• 1999

The aim of treatment of cleft lip and palate is to correct the cleft and associated problems surgically and thus hide the anomaly so that patients can lead normal lives. This correction involves surgically producing a face that does not attract attention, a vocal apparatus that permits intelligible speech, and a dentition that allows optimal function and esthetics. In neonatal periods, gross distortion of tissues surrounding the cleft requires considerable effort and time due to post operative functional defect and scarring and induces milk feeding problem, malocclusion of deciduous or permanent dentition, congenital missing teeth, skeletal dysplasia. The occurrence of a cleft deformity is a source of considerable shock to the parents of an afflicted baby, and the most appropriate approach is very important things. Thus we tried to analysis of dental arch, shape and size of deformity in cleft patients. The results were obtained as follows. 1. When the cast measurements of UCLP subjects at first visit it was found that the mean length was 9.29mm at the alveolar cleft width, also that was 11.7mm at the anterior width and 14mm at the posterior cleft width. 2. Comparison of UCLP group at first visit and just lip surgery, it was found that the older group showed a insignificant reduction in the width of the cleft in the alveolar, canine, and tuberosity regions. 3. The maxillary casts of the UCLP group at 6 months differ Significantly from those of the at 3 months in both length and width. but there was no statistical difference except anterior ridge length of nonclefted site. 4. Comparison at 6 months and 18 months, there was a greater change in length of the alveolar cleft width, intercanine width, and anterior cleft width. Maxillary arch became wider at both the canine region and intertuberosity region. also posterior anteroposterior length was increased but anterior AP length was decreased from 8.1mm to 7.7mm. There was meaningful increase at intertuberosity length; however, a significant reduction in width t-t'