• Journal of Chest Surgery
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• v.46 no.4
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• pp.279-284
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• 2013

Background: Sternal dehiscence is one of the most troublesome complications following cardiac surgery. Treatment failure and consequent lethal outcomes are very common. The aim of this study was to evaluate titanium plate fixation as a treatment for sternal dehiscence following major cardiac surgery. Materials and Methods: Between 2010 and 2012, 17 patients underwent sternal reconstruction using horizontal titanium plating for the treatment of post-cardiac-surgery sternal dehiscence. The plates were cut and shaped, and then were fixed to corresponding costal segments using 2-3 titanium screws per each side. Results: The median age of our patients was 66 years (range, 50 to 78 years) and 9 were female. Indications for sternal reconstruction included aseptic sternal dehiscence in 3 patients and osteomyelitis in 14 patients including 6 patients who were diagnosed with mediastinitis. During the operation, sternal resection and autologous flap interposition were combined in 11 patients. One patient died due to sepsis. Two patients required additional soft tissue wound revisions. Another patient presented with a tuberculous wound infection which was resolved using anti-tuberculosis medications. The postoperative course was uncomplicated in the other 13 patients. Conclusion: Titanium plate fixation that combines appropriate debridement and flap interposition is very effective for the treatment of sternal dehiscence following major cardiac surgery.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.2
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• pp.33-41
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• 2012

The component cooling water heat exchangers are critical components in a nuclear power plant. As the operation years of the heat exchanger go by, the maintenance costs required for continuous operation also increase. Most heat exchangers have carbon steel shells, tube support plates and flow baffles. The titanium tube is susceptible to flow induced vibration. The damage on carbon steel tube support rod and titanium tube around cooling water entrance area is inevitable. Therefore, analysis of internal flow around the component cooling water entrance and tube channel is a good opportunity to seek for failure prevention practice and maintenance method. The numerical study was carried out by FLUENT code to find out the causes of tube failure and its location.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.67-73
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• 1987

The feasibility for a practical use of underwater wet arc welding process is experimentally investigated by using low hydrogen and high oxide type electrodes and TMCP steel plates. Main results are summarized as follows: 1)The absorption speed of the coated low hydrogen and high titanium oxide type eletrodes becomes constant after about 30 minutes in water, and more steeping time in water does not influnce welding arc behavior. 2) By bead appearance and X-ray inspection, the high titanium oxide type electrode is better than the low hydrogen type in underwater arc welding process. 3) The mechanical properties of underwater wet arc welds depend upon welding conditions more than those of in-air welds, and the optimum welding condition can be obtained. 4) Because of quenching effect by rapid cooling rate in underwater wet welding, the maximum hardness of HAZ is increased relatively higher in underwater wet welding, process.

• Journal of Chest Surgery
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• v.51 no.5
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• pp.308-311
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• 2018

We herein present a new surgical reconstruction technique for large chest wall defects after resection of advanced chest wall tumors.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.204-206
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• 2003

Ti/Steel 클래드 판재를 제조하기 위하여 티타늄과 강판을 직접 접합하는 경우 접합 계면에 취성이 강한 금속간화합물 및 TiC 탄화물이 발생하여 계면접합강도를 저하시키는 단점이 있다. 이러한 단점을 보완하기 위하여 본 연구에서는 티타늄과 강판 사이에 니켈 박판을 삽입한 후 1223-1323K 온도구간에서 접합 실험하였다. 특히, 온도의 변화에 따라 티타늄과 강판의 계면에 발생되는 금속간화합물의 종류 및 반응층의 크기 변화에 따른 기계적 특성을 조사하였다.

• Archives of Craniofacial Surgery
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• v.11 no.2
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• pp.85-90
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• 2010

Purpose: The goals of a blow-out fracture reconstruction are to restore the osseous continuity, provide support for the orbital contents and prevent functional and anatomic defects. Over the past several years, a range of autogenous and synthetic implants have been used extensively in orbital reconstructions. None of these implants have any absolute indications or contraindications in certain clinical settings. However, in extensive blow-out fractures, it is difficult to restore support of the orbital contents, which can cause more complications, such as enophthalmos. This study examined the clinical outcomes of extensive or comminuted blow-out fractures that were reconstructed by the simultaneous use of a titanium mesh plate and $Medpor^{(R)}$. Methods: Eighty six patients with extensive orbital fractures, who were admitted between March 1999 and February 2007, were reviewed retrospectively. The patients' chart and CT were inspected for review. Twenty three patients were operated on with both a titanium mesh plate (Matrix MIDFACE pre-formed orbital plate, Synthes, USA) and $Medpor^{(R)}$ (Porex, GA, USA). The patients underwent pre-operative CT scans to evaluate the fracture site and measure the area of the fracture. A transconjunctival approach was used, and titanium mesh plates were inserted subperiosteally with screw fixation. $Medpor^{(R)}$ was inserted above the titanium mesh plate. The patients were evaluated post-operatively for enophthalmos, diplopia, sensory disturbances and eyeball movement for a period of at least 6 months. Results: No implant-related complications were encountered during the follow-up period. Enophthalmos occurred in 1 patient, 1 patient had permanent sensory disturbance, and 3 patients complained of ocular pain and fatigue, which recovered without treatment. Although there were no significance differences between groups, the use of 2 implants had fewer complications. Therefore, it can be an alternative method for treating blow out fractures. Conclusion: The use of both a titanium mesh plate and $Medpor^{(R)}$ simultaneously may be a safe and acceptable technique in the reconstruction of extensive blow-out fractures.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.112-123
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• 2006

Purpose: The biocompatibility and bio-adhesive property of a dental implant abutment are important for proper soft tissue healing and maintenance of osseointegration of implant. However, studies of soft tissue healing and mucosal attachment of various materials of implant abutment other than titanium are still needed. In this study, cell attachment, proliferation, cytotoxicity of human gingival fibroblast for ceramic, gold alloy, Ni-Cr alloy and, commercially available pure titanium as a control were evaluated, using MTS and scanning electron microscopy. Materials and Methods: Specimen was designed to disc, 4mm diameter and 1mm thickness, made of ceramic, gold alloy, Ni-Cr alloy and commercially available pure titanium. Primary culture of human gingival fibroblasts were grown in Dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. Cells were inoculated in the multiwell plates placed the specimen disc. Cell Titer 96 AQucous One Solution Cell Proliferation Assay were done after 1hour 3hours, 24hours, 3days, 5days of incubation. The discs were processed for scanning electron micrography to evaluate cell attachment and morphologic change. Results: The results were obtained as fellows. 1. The ceramic showed high cell attachment and proliferation and low cytotoxicity, which is as much bioadhesive and biocompatible as titanium. 2. The gold alloy represented limited proliferation of human gingival fibroblast and the highest cytotoxicity among tested materials (p<0.05). 3. The Ni-Cr alloy limited the proliferaion of the human gingival fibroblast compared to titanium(p<0.05) but cytotoxicity on the bottom of well was not so considerable, compared to titanium. 4. On the scanning electron micrographs , the ceramic showed good attachment and proliferation of human gingival fibroblast, which was similar to titanium. But gold alloy and Ni-Cr alloy showed the shrinkage of gingival fibroblast both after 24 hours and 3 days. On 5th day, small amount of the human gingival fibroblast proliferation was observed on the Ni-Cr alloy, while the shrinkage of gingival fibroblast was still observed on the gold alloy. Conclusions: These results suggest that the ceramic abutment is as biocompatible as titanium to make proper mucosal seal. The gold alloy has a high cytotoxicity to limit proliferation of gingival fibroblast, which suggest limited use on the anterior tooth where soft tissue healing is recommeded.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.3
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• pp.566-576
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• 1997

This study was performed to evaluate the tensile strength of solder joint in titanium and the wettability of 14K gold solder on titanium. Two pieces of titanium rod 30 mm in length and 3mm in diameter were butt-soldered with a 14K gold solder using the electric resistance heating under flux-argon atmosphere, the infrared heating under argon atmosphere, and the infrared heating under vacuum-argon atmosphere. A tensile test was performed at a crosshead speed of 0.5 mm/min, and fracture surfaces were examined by SEM. To evaluate the wettability of 14K gold solder on titanium, titanum plates of a $17{\times}17{\times}1mm$ were polished with #80-#2000 emery papers, and the spreading areas of solder 10 mg were measured by heating at 840 * for 60 seconds. The solder-matrix interface regions were etched by the solution of 10% KCN-10% (NH4)2S2O8, and analyzed by EPMA. The results obtained were summarized as follows ; 1. The maximum tensile strength was obtained when the titanium surface was polished with #2000 emery paper and soldered using the electric resistance heating under flux-argon atmosphere. Soldering strengths showed the significant difference between the electric resistance heating and the infrared heating(p<0.05). 3. The fracture surfaces showed the aspect of brittle fracture, and the failure developed along the interfaces of solder-matrix reaction zone. 4. The EPMA data for the solder-matrix interface region revealed that the diffusion of Au and Cu occurred to the titanium matrix, and the reaction zone showed the higher contents of Au, Cu and Ti than others.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.458-464
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• 2011

Purpose: Metacarpal fractures are common hand injury that may require operative intervention to ensure adequate reduction and stabilization. Traditionally, titanium miniplate was used for rigid fixation of bone fractures. However, the use of permanent plate lends itself to multiple complications such as infection, exposure of the hardware, tendon adhesions, tendon rupture, prolonged pain, bony atrophy and osteoporosis (stress shielding), metal sensitization, and palpation under the skin. This study evaluated the usefulness and stability of biodegradable plates and screws for treatment of metacarpal bone fractures. Methods: There was 17 patients who had surgery for metacarpal bone fracture from April 2007 to June 2010. All patients had open reduction and internal fixation. We used absorbable plates and screws (Inion CPS$^{(R)}$) for internal fixation. Postoperative results were assessed with x-ray. Stability of plates and screws, healing process and its complications were observed by clinical and radiographic assessment. Results: All patients were successfully reduced of bone fracture, and fixations with absorbable plates and screws were stable. The mean follow up period was 7.1 months. 2 patients complained postoperative pain, but they were relieved with analgesics. All patients experienced transient stiffness, but they were relieved with active assistive range of motion after removal of splint. No patients suffered complications which could be occurred by using metallic plate. Conclusion: There was no critical complications such as re-fracture or nonunion among patients. No patients suffered side effects related with metallic implants. Biodegradable implants can offer clinically stable and attractive alternative to metallic implants to stabilize metacarpal bone fractures in the hand.

• The Journal of Advanced Prosthodontics
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• v.12 no.3
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• pp.157-166
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• 2020

PURPOSE. The aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating. MATERIALS AND METHODS. This study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZ-coated titanium abutments. RESULTS. In the mechanical study, 400 ㎛ thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZ-coated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65-663.7 N) for incisor teeth. CONCLUSION. In this study, the plasmasprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.