• Archives of Craniofacial Surgery
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• v.9 no.2
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• pp.105-109
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• 2008

Temporomandibular joint(TMJ) and dental occlusion are important in functional aspect as well as in cosmetic aspect for craniofacial surgery such as orthognathic and traumatic surgery. During these operations, appropriate maxillomandibular fixation(MMF) is especially necessary to conserve or reconstruct, dynamic TMJ and functional occlusion. Arch bar is one of the most popular method to gain proper MMF. Seventeen patients including 5 patients with mandibular fracture, 12 patients with orthognathic surgery(6 patients had relatively normal occlusion, however 6 patients had facial anomalies such as hemifacial microsomia with irregular occlusal plane.) were joined in this study. Arch bar was contoured on the dental cast, which was prepared for model surgery, prior to apply it on the facial anomaly patient. On using pre-contoured arch bar, patients felt better during the procedure and surgeons saved time. Moreover, well-contoured arch bar promises precise transmission of force on the bone, which implies surgeons do not need to worry about the occlusion while fixing bony structures. Authors suggest how to apply arch bar to satisfy basic theories about dental row and occlusion based on the experience. In addition, it is proposed to contour arch bar on the dental impression prior to apply it on the patient who has irregular and complex occlusal plane.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.192-199
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• 2016

Triple tooth is rare in primary dentition; it is the abnormal fusion of three teeth. There are a few reports of double teeth, but triple teeth are rare. These multiple teeth create several clinical problems, not only esthetic problems but also a high caries susceptibility, congenital missing permanent tooth germ(s), orthodontic problems, and periodontal problems. They also make it difficult to perform pulp treatment because of the complex tooth structure. A 1-year 7-month-old male underwent a partial pulpotomy with mineral trioxide aggregate (MTA) when pulp exposure caused by deep caries occurred at a maxillary anterior triple tooth in the first case. The second case was a 1-year 9-month-old male presenting with a fracture line at a mandibular anterior triple tooth. After removing the fractured fragment, a pulpectomy was performed at the remaining primary lateral incisors. Specific complications were not observed during 24 and 6 months of follow-up, respectively.

• Biomedical Science Letters
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• v.21 no.4
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• pp.181-187
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• 2015

Osteoporosis is one of the diseases caused by accumulation of effects from complex interactions between genetic and environmental factors. Aging is the major cause for osteoporosis, which normally increases skeletal fragility and bone fracture especially among the elder. "Omics" refers to a specialized research field dealing with high-throughput biological data, such as genomics, transcriptomics, proteomics or metabolomics. Integration of data from multi-omics has been approved to be a powerful strategy to colligate biological phenomenon with multiple aspects. Actually, integrative analyses of "omics" datasets were used to present pathogenesis of specific diseases or casual biomarkers including susceptible genes. In this study, we evaluated the proposed relationship of novel susceptible genes (TREML2, HTR1E, and GLO1) with osteoporosis, which genes were obtained using multi-omics integration analyses. To this end, SNPs of the susceptible genes in the Korean female cohort were analyzed. As a result, one SNP of HTR1E and five SNPs of TREML2 were identified to associate with osteoporosis. The highest significant SNP was $rs6938076^*$ of TREML2 (OR=0.63, CI: 0.45~0.89, recessive P=0.009). Consequently, the susceptible genes identified through the multi-omics analyses were confirmed to have association with osteoporosis. Therefore, multi-omics analysis might be a powerful tool to find new genes associated with a disease. We further identified that TREML2 has more associated with osteoporosis in females than did HTR1E.

• Archives of Plastic Surgery
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• v.45 no.4
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• pp.325-332
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• 2018

Background Zygomaticomaxillary complex (ZMC) fractures mostly occur in the form of tripod fractures. The surgical field is accessed using a combination of three classic approaches. However, the subciliary incision may have unfavorable aesthetic results. Herein, the authors report the advantages of the extended transconjunctival approach (ETA) combined with T-bar screw reduction in minimizing scarring and complications for the treatment of ZMC fractures. Methods A total of 26 patients underwent ZMC reduction through the ETA and intraoral approach. A skin incision measuring roughly 5 to 8 mm in length was placed following the lateral canthal skin crease. After releasing the inferior crus of the lateral canthal tendon for canthotomy, the medial periosteum of the lateral orbital rim was preserved for canthal reattachment. A limited subperiosteal dissection and partial relaxing incision of the orbicularis oculi were performed to expose the fracture line of the inferior orbital rim and zygomaticofrontal suture. Reduction was performed using a T-bar screw through the transconjunctival incision and an elevator through the intraoral incision. Results The aesthetic and functional results were excellent. Successful reduction was achieved and the skin incision was less than 8 mm in 20 cases (76.9%). Only six patients had an additional skin incision (less than 5 mm) to achieve reduction. No cases of ectropion, entropion, or excessive scarring were noted. Conclusions The ETA using a T-bar screw is a useful method for maximizing aesthetic results in ZMC fractures, with the advantages of minimal scarring, faster recovery, and maintenance of pretarsal fullness.

• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.1-7
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• 2017

We propose a complex crack generation technique which is represented when impact is applied to glass. The crack patterns expressed when external forces are applied to the glass are classified into dense, radial, and concentric cracks, and we use procedural methods to efficiently represent crack patterns. Based on the input external force, we synthesize the crack example and apply the L-system based on this example to model the propagation shape of the crack in real time. Although physics based crack generation can analyze and model accurate cracks, it has a disadvantage of slow computation because of its high computational cost, and procedural methods have a relatively fast rate of continuity, but are not sufficient to capture accurate crack characteristics. We modeled cracks in glass using L-system to achieve both of these advantages. As a result, it realistically represented the microscopic crack patterns of glass in real time.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.5
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• pp.68-79
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• 1998

In the years, the concern about high-strength concrete which is new material has been heightened as a result of active research and development. Recently, as the building structure has been being bigger, higher, longer and more specialized, the demand of material with high-strength concrete for building has been increasing. The demand of high -strength concrete is expected to increase with expansion of usage about the complex concrete structures such as bridge structure as well as nuclear plants, underground structures, hydraulic structures and arctic area sturctures. In this research, silica-fume was used as an admixture in order to get a high-strength concrete. Water/binder ration was limited no more than 18 percent and the amount of unit cement was increased. In this study, a number of trial in concrete mix was carried out to get optimal mix design, and the target slump with $10{\pm}2cm$ was set for in-situ construction. High-strength concrete with cylinder strength of 1,200kgf/$cm^2$ in the 28-days was produced and tested. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns, fracture modes. The load versus strain and load versus deflection relations were obtained form the static test. The test results were compared with the shear strengths predicted by the equations of ACI code 318-89 and orther researchers. Based on the test results, shear strength equation of reinforced concrete beam using high strength concrete was proposed. Form an evaluation of the results of this experimental investigation, it was concluded that shear strength after diagonal tention cracking diminished with the increase in compressive strength for beams.

• Archives of Reconstructive Microsurgery
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• v.8 no.2
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• pp.130-138
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• 1999

The lower extremity injuries are extremely increasing with the development of industrial & transportational technology. For the lower extremity injuries that result from high-energy forces, particularly those in which soft tissue and large segments of bone have been destroyed and there is some degree of vascular compromise, the problems in reconstruction are major and more complex. In such cases local muscle coverage is probably unsuccessful, because adjacent muscles are destroyed much more than one can initially expect. Reconstruction of the lower extremity has been planned by dividing the lower leg into three parts traditionally The flaps available in each of the three parts are gastrocnemius flap for proximal one third, soleus flap for middle one third and free flap transfer for lower one third. Microvascular surgery can provide the necessary soft tissue coverage from the remote donnor area by free flap transfer into the defect. Correct selection of the appropriate recipient vessels is difficult and remains the most important factor in successful free flap transfer. Vascular anastomosis to recipient vessels distal to the zone of injury has been advocated and retrograde flow flaps are well established in island flaps. Retrograde flow anastomosis could not interrupt the major blood vessels which were essential for survival of the distal limb, the compromise of fracture or wound healing might be prevented. During 5 years, from March 1993 to Feb. 1998, we have done 68 free flap transfers in 61 patients to reconstruct the lower extremity. From analysis of the cases, we concluded that for the reconstruction of the lower extremity, free flap transfer yields a more esthetic and functional results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.443-449
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• 2004

Methods for mixing variable types of steel fibers have been developed recently to suppress outbreak of crack or to control the width of crack and improve the load resistible capacity at the same time. On the other hand, uncertainty by complex nature of destruction dynamics of steel fiber reinforced concrete(SFRC) is included. In this study, analysis of reliance considering uncertainty of SFRC beam is done. For this, intensity limit state model was proposed. Moreover, characteristic values about almost every kinds of probability variables were collected and presented according to home and foreign references. Process of improving uncertainty from the result of experiments by Bayseian updating method is also proposed on the purpose of offering better statistical characteristic values with more data in the new future. Fatigue fracture probability equation is proposed and needed statistical characteristic values were presented to analyze fatigue reliance

• Journal of Korea Foundry Society
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• v.27 no.5
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• pp.203-208
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• 2007

The high temperature properties of vanadium and molybdenum added high silicon ductile iron, so called V-Mo-Si ductile iron, were investigated. The (V,Mo) complex carbides and Mo carbides precipitated at the cellular boundaries of the as-cast specimens. The microhardness of the (V,Mo) carbides were in the range of 553-619, while that of the Mo carbides in the range of 341-390. The thermo-mechanical tests were carried out with a Gleeble system at 700 and $800^{\circ}C$ under vacuum condition. The tensile strengths of the specimen tested at $700^{\circ}C$ with the dynamic deformation rate of 50 mm/sec and those with the static deformation rate of 0.15 mm/sec were 235.7 and 115.3 MPa, while the reduction in area were 23.7 and 22.4%, respectively. At the high dynamic deformation rates, the tensile strength was steeply increased due to promoting the brittle fracture of pearlite in the matrix of the specimens. But the changes of the reduction in area with the deformation rates on the same specimens were negligible. The weight gain of the V-Mo-Si specimens oxidized in the air atmosphere for 6 hours at 800 and $900^{\circ}C$ were 1.1 and 4.1.%, respectively. The cross-sectional microstructure of oxidized specimens consisted of the porous external scale layer grown outside from the original surface, the dense internal scale layer grown into the original surface, the decarburized ferrite layer between the internal scale and the matrix of base metal. The (V,Mo) carbides and Mo carbides formed in the matrix of as-cast specimen did not decompose during oxidation at 900 for 24 hours in air atmosphere.

• Archives of Craniofacial Surgery
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• v.19 no.3
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• pp.175-180
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• 2018

Background: The facial bone has a complex structure compared to other bones, and various types of fractures can occur due to its characteristics. Among them, in comminuted fractures of anterior maxillary wall, multiple depressed and impacted bony segments cannot be reduced easily when performing internal fixation using plates and screws or wires, and inadequate restoration leads to a range of complications. This paper introduces an alternative technique using a resorbable mesh with fibrin glue to restore comminuted fractures of anterior maxillary wall. Methods: Thirteen patients were diagnosed with comminuted fractures of anterior maxillary wall between March 2017 and February 2018 in the authors' hospital. All patients with comminuted fractures of anterior maxillary wall underwent restoration using resorbable mesh with fibrin glue. The patients' demographics, causes of facial trauma, mean operation time, length of hospital stay, follow-up period, and complications were recorded. Results: No major complications and only one hypoesthesia of the skin area was noted. Three months after surgery, the hypoesthesia recovered completely. After surgery (mean, 3.9 months; range, 2-12 months), computed tomography showed that the bone fragments in all patients were fixed successfully in their anatomical places. Conclusion: In comminuted fractures of anterior maxillary wall, the use of a resorbable mesh with fibrin glue can be an advantageous and effective method for a successful restoration without complications.