• 제목/요약/키워드: Implant Metal

검색결과 227건 처리시간 0.041초

흡수성 반월상 연골나사를 사용한 얇은 골연골 골절의 치료 - 증례 보고 - (Biodegradable Meniscus Screw Fixation of Thin Flap Osteochondral Fracture - Two Case Report -)

  • 전재균;선두훈;송인수;김영우;정재용;이봉주
    • 대한관절경학회지
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    • 제14권2호
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    • pp.131-134
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    • 2010
  • 관절내 골연골 골절은 적절한 치료가 이루어 지지 않은 경우 골관절염을 초래하여 통증과 기능장애를 초래할 수 있다. 골 연골 골절의 크기가 큰 경우에는 관혈적 정복 및 금속고정 수술등으로 치료를 할 수 있으나, 골편의 두께가 2mm 이하로 얇은 경우 튼튼한 고정력을 얻기 어려워 제거 하는 경우가 많았다. 저자들은 대퇴 내과에 발생한 박리성 골연골염 환자와 슬개골 골절로 골편의 두께가 2mm이하인 환자에서 흡수성 반월상 연골나사를 이용하여 좋은 결과를 얻었기에 보고하고자 한다.

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Fe ion을 주입한 1.55$\mu\textrm{m}$ MQW 레이저 다이오드의 전기적 절연 특성

  • 강병권;김태곤;박윤호;우덕하;이석;김선호;강광남;송종한;황정남;박승한
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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    • pp.91-91
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    • 1999
  • 광소자 기술은 정보 전달 및 저장 기술의 지속적인 증가 요구에 따라 발전을 거듭하여 왔다. 특히 광통신 및 저장 기술에서 광원으로 사용되는 레이저 다이오드는 안정되면서 쉽게 제작할 수 있어야 한다. 이온 주입 방법은 반도체 공정에서 광범위하게 사용되는 공정이며 이미 소자측면에서 안정성이 확보되었다고 볼 수 있으나 대부분 메모리 등의 실리콘 반도체에서 이용되어 왔다. 최근에는 화합물 반도체 분야에서도 적용하는 예가 증가되고 있으나 광원으로 사용되는 레이저 다이오드의 경우는 우수한 품질의 반도체 층이 요구되며 따라서 damage가 큰 이온 주입 방법을 이용한 연구는 아직 많이 이루어져 있지 않다. 본 연구에서는 레이저 다이오드 구조의 성장측에 국부적으로 Fe 이온을 주입하여 도파로를 형성하여 광을 구속하여 도파시키는 동시에 전기적으로도 도파로 부분으로만 다이오드가 형성되도록 하고자 한다. 먼저 p층의 전기적 절연에 필요한 조건을 확보하기 위하여 CBE를 사용하여 Fe가 doping 된 SI-InP wafer 위에 p-InP (Be:5x1017 cm-3)층을 1.2$mu extrm{m}$ 성장한 후 ohmic 층으로 p-InGaAs (Be:1x1019 cm-3)을 0.1$\mu\textrm{m}$ 성장한 시료에 고에너지 이온 주입 장치를 사용하여 Fe 이온을 1MeV, 1.6meV의 에너지에 각각 1x1014cm-2, 2x1014cm-2 의 dose로 전면에 implant 하였다. 이 시료를 tube furnace에서 500, 600, $700^{\circ}C$각각 10분씩 annealing 한 후 재성장을 확인하기 위하여 DCXRD을 측정하였다. 그림 1은 DCXRD rocking curve로 annealing 하기 전 후의 In rich에서 side peak의 감소를 확인 할 수 있었는데 이는 damage가 어느 정도 복구되었음을 의미한다. 또한 절연 특성을 확인하기 위하여 ohmic metal을 증착하여 Hall 효과를 측정하였다. 그림 2에 보이는 것과 같이 annealing 온도가 증가함에 따라 면저항이 크게 증가함을 볼 수 있으며 이온 주입하기 전의 시료에 비해 104 이상의 저항을 갖을 수 있다. 향후 이러한 결과를 바탕으로 1.55$\mu\textrm{m}$ LD 구조에서 발진 특성을 관찰할 계획이다.

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전자파 흡수율(SAR) 시뮬레이션 기법과 5G 주파수 대역에서의 인공 치아가 삽입된 인체 머리 모델의 전자파 흡수율 시뮬레이션 결과 (Simulation Methods of Electromagnetic Wave Specific Absorption Rate (SAR) and the Simulation Results of Human Head Model with Dental Implants in 5G Frequency Band)

  • 김창균;이성수
    • 전기전자학회논문지
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    • 제22권3호
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    • pp.854-857
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    • 2018
  • 다양한 무선기기가 일상화됨에 따라 전자파가 인체에 미치는 영향에 대해 분석할 필요성이 증가하고 있다. 전자파가 인체에 미치는 영향을 나타내는 파라미터가 전자파 흡수율(SAR: specific absorption rate)인데, 이는 단순히 인체 조직만 대상으로 하고 있어 인공 치아 등의 금속 인공물이 삽입된 경우에는 전자파가 미치는 영향을 평가하기가 쉽지 않다. 본 논문에서는 SAR을 시뮬레이션하기 위한 방법을 소개하고 실제로 SAR을 시뮬레이션 하였다. 30 GHz 5세대 이동통신(5G) 주파수 대역에서 인공 치아가 삽입된 인체 머리 모델의 SAR은 최고치 $2.50{\times}10^{-3}W/kg$, 평균치 $8.58{\times}10^{-7}W/kg$으로 국내 허용 기준치 1.6 W/kg에 절대적으로 못 미침을 알 수 있다.

Bone-like Apatite Morphology on Si-Zn-Mn-hydroxyapatite Coating on Ti-6Al-4V Alloy by Plasma Electrolytic Oxidation

  • Park, Min-Gyu;Choe, Han-Cheol
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2017년도 춘계학술대회 논문집
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    • pp.158-158
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    • 2017
  • Titanium and its alloys have been used in the field dental and orthopedic implants because of their excellent mechanical properties and biocompatibility. Despite these attractive properties, their passive films were somewhat bioinert in nature so that sufficient adhesion of bone cells to implant surface was delayed after surgical treatment. Recently, plasma electrolyte oxidation (PEO) of titanium metal has attracted a great deal of attention is a comparatively convenient and effective technique and good adhesion to substrates and it enhances wear and corrosion resistances and produces thick, hard, and strong oxide coatings. Silicon(Si), Zinc(Zn), and Manganese(Mn) have a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. And, Zn has been shown to be responsible for variations in body weight, bone length and bone biomechanical properties. Also, Mn influences regulation of bone remodeling because its low content in body is connected with the rise of the concentration of calcium, phosphates and phosphatase out of cells. The objective of this work was research on bone-like apatite morphology on Si-Zn-Mn-hydroxyapatite coating on Ti-6Al-4V alloy by plasma electrolytic oxidation. Anodized alloys were prepared at 280V voltage in the solution containing Si, Zn, and Mn ions. The surface characteristics of PEO treated Ti-6Al-4V alloy were investigated using XRD, FE-SEM, and EDS.

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An analysis on the factors responsible for relative position of interproximal papilla in healthy subjects

  • Kim, Joo-Hee;Cho, Yun-Jung;Lee, Ju-Youn;Kim, Sung-Jo;Choi, Jeom-Il
    • Journal of Periodontal and Implant Science
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    • 제43권4호
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    • pp.160-167
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    • 2013
  • Purpose: This study examined the factors that can be associated with the appearance of the interproximal papilla. Methods: One hundred and forty-seven healthy interproximal papillae between the maxillary central incisors were examined. For each subject, a digital photograph and periapical radiograph of the interdental embrasure were taken using a 1-mm grid metal piece. The following parameters were recorded: the amount of recession of the interproximal papilla, contact point-bone crest distance, contact point-cemento-enamel junction (CEJ) distance, CEJ-bone crest distance, inter-radicular distance, tooth shape, embrasure space size, interproximal contact area, gingival biotype, papilla height, and papilla tip form. Results: The amount of recession of the interproximal papilla was associated with the following: 1) increase in contact point-bone crest, contact point-CEJ, and CEJ-bone crest distance; 2) increase in the inter-radicular distance; 3) triangular tooth shape; 4) decrease in the interproximal contact area length; 5) increase in the embrasure space size; and 6) flat papilla tip form. On the other hand, the amount of gingival recession was not associated with the gingival biotype or papilla height. In the triangular tooth shape, the contact point-bone crest distance and inter-radicular distance were longer, the interproximal contact area length was shorter, and the embrasure space size was larger. The papilla tip form became flatter with increasing inter-radicular distance and CEJ-bone crest distance. Conclusions: The relative position of the interproximal papilla in healthy subjects was associated with the multiple factors and each factor was related to the others. A triangular tooth shape carries a higher risk of recession of the interproximal papilla because the proximal contact point is positioned more incisally and the bone crest is positioned more apically. This results in an increase in recession of the interproximal papilla and flat papilla tip form.

Design and 3D-printing of titanium bone implants: brief review of approach and clinical cases

  • Popov Jr, Vladimir V.;Muller-Kamskii, Gary;Kovalevsky, Aleksey;Dzhenzhera, Georgy;Strokin, Evgeny;Kolomiets, Anastasia;Ramon, Jean
    • Biomedical Engineering Letters
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    • 제8권4호
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    • pp.337-344
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    • 2018
  • Additive manufacturing (AM) is an alternative metal fabrication technology. The outstanding advantage of AM (3D-printing, direct manufacturing), is the ability to form shapes that cannot be formed with any other traditional technology. 3D-printing began as a new method of prototyping in plastics. Nowadays, AM in metals allows to realize not only net-shape geometry, but also high fatigue strength and corrosion resistant parts. This success of AM in metals enables new applications of the technology in important fields, such as production of medical implants. The 3D-printing of medical implants is an extremely rapidly developing application. The success of this development lies in the fact that patient-specific implants can promote patient recovery, as often it is the only alternative to amputation. The production of AM implants provides a relatively fast and effective solution for complex surgical cases. However, there are still numerous challenging open issues in medical 3D-printing. The goal of the current research review is to explain the whole technological and design chain of bio-medical bone implant production from the computed tomography that is performed by the surgeon, to conversion to a computer aided drawing file, to production of implants, including the necessary post-processing procedures and certification. The current work presents examples that were produced by joint work of Polygon Medical Engineering, Russia and by TechMed, the AM Center of Israel Institute of Metals. Polygon provided 3D-planning and 3D-modelling specifically for the implants production. TechMed were in charge of the optimization of models and they manufactured the implants by Electron-Beam Melting ($EBM^{(R)}$), using an Arcam $EBM^{(R)}$ A2X machine.

Comparative clinical study of the marginal discrepancy of fixed dental prosthesis fabricated by the milling-sintering method using a presintered alloy

  • Kim, Mijoo;Kim, Jaewon;Mai, Hang-Nga;Kwon, Tae-Yub;Choi, Yong-Do;Lee, Cheong-Hee;Lee, Du-Hyeong
    • The Journal of Advanced Prosthodontics
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    • 제11권5호
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    • pp.280-285
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    • 2019
  • PURPOSE. The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS. Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (${\alpha}=.05$). RESULTS. Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION. The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.

Optimization of exposure parameters and relationship between subjective and technical image quality in cone-beam computed tomography

  • Park, Ha-Na;Min, Chang-Ki;Kim, Kyoung-A;Koh, Kwang-Joon
    • Imaging Science in Dentistry
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    • 제49권2호
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    • pp.139-151
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    • 2019
  • Purpose: This study was performed to investigate the effect of exposure parameters on image quality obtained using a cone-beam computed tomography (CBCT) scanner and the relationship between physical factors and clinical image quality depending on the diagnostic task. Materials and Methods: CBCT images of a SedentexCT IQ phantom and a real skull phantom were obtained under different combinations of tube voltage and tube current (Alphard 3030 CBCT scanner, 78-90 kVp and 2-8 mA). The images obtained using a SedentexCT IQ phantom were analyzed technically, and the physical factors of image noise, contrast resolution, spatial resolution, and metal artifacts were measured. The images obtained using a real skull phantom were evaluated for each diagnostic task by 6 oral and maxillofacial radiologists, and each setting was classified as acceptable or unacceptable based on those evaluations. A statistical analysis of the relationships of exposure parameters and physical factors with observer scores was conducted. Results: For periapical diagnosis and implant planning, the tube current of the acceptable images was significantly higher than that of the unacceptable images. Image noise, the contrast-to-noise ratio (CNR), the line pair chart on the Z axis, and modulation transfer function (MTF) values showed statistically significant differences between the acceptable and unacceptable image groups. The cut-off values obtained using receiver operating characteristic curves for CNR and MTF 10 were useful for determining acceptability. Conclusion: Tube current had a major influence on clinical image quality. CNR and MTF 10 were useful physical factors that showed significantly associations with clinical image quality.

Clinical outcomes of bending versus non-bending of the plate hook in acromioclavicular joint dislocation

  • Joo, Min Su;Kwon, Hoi Young;Kim, Jeong Woo
    • Clinics in Shoulder and Elbow
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    • 제24권4호
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    • pp.202-208
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    • 2021
  • Background: We aimed to assess the effect of plate hook bending in treatment of acromioclavicular (AC) dislocation by analyzing clinical and radiological results according to the angle of the plate hook (APH). Methods: This was a retrospective, observational, case-control study including 76 patients with acute AC joint dislocation that were divided into two groups according to treatment with bent or unbent plate hook. The visual analog scale (VAS), the American Shoulder and Elbow Surgeons (ASES) shoulder score, and range of motion (ROM) were evaluated as clinical outcomes. Comparative coracoclavicular distance (CCD) was measured to evaluate radiological outcomes. Results: While the VAS and ASES of the bending group at 4 months after surgery were significantly higher (p=0.021 and p=0.019), the VAS and ASES of the bending group at other periods and ROM of the bending group showed no significant difference. The initial CCD decreased from 183.2%±25.4% to 114.3%±18.9% at the final follow-up in the bending group and decreased from 188.2%±34.4% to 119.1%±16.7% in the non-bending group, with no statistical difference (p=0.613). The changes between the initial and post-metal removal CCD were 60.2%±11.2% and 57.3%±10.4%, respectively, with no statistical difference (p=0.241). The non-bending group showed greater subacromial osteolysis (odds ratio, 3.87). Pearson's coefficients for the correlation between APH and VAS at 4 months after surgery and for that between APH and ASES at 4 months after surgery were 0.74 and -0.63 (p=0.027 and p=0.032), respectively. Conclusions: The APH was associated with improved postoperative pain and clinical outcomes before implant removal and with reduced complications; therefore, plate hook bending is more useful clinically during plate implantation.

금속 적층제조에서의 격자구조 설계변수에 따른 탄성계수 분석 (Design of lattice structure for controlling elastic modulus in metal additive manufacturing)

  • 문인용;송영환
    • 한국결정성장학회지
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    • 제33권6호
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    • pp.276-281
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    • 2023
  • 적층제조 공정의 높은 설계자유도에 의해 기존 공정으로 성형이 어려운 형상이 적용된 제품의 제작이 가능해짐에 따라 복잡한 구조를 갖는 기능성 구조에 대한 연구자들의 관심이 증가되고 있다. 타이타늄 합금으로 제작되는 인체 삽입형 임플란트의 경우, 뼈와의 친화성을 확보하기 위해 다차원 격자구조를 적용하여 강도 및 탄성계수를 뼈와 유사한 수준으로 조절하고 있다. 따라서 격자구조의 설계 변수에 따른 기계적 특성에 대한 데이터 베이스 확보 및 관련 시뮬레이션 기술 개발은 개인 맞춤형 인플란트 제작을 효율적으로 수행할 수 있게 할 것이라 생각된다. 따라서 본 연구에서는 Ti-6Al-4V 합금 소재를 적용하여 설계변수별 격자구조체를 제작하고 이에 대한 탄성계수를 측정하였으며 그 결과를 시뮬레이션과 비교하여 정확한 탄성계수 예측을 위한 유한요소해석 방안을 제시하였다.