• Title/Summary/Keyword: Ceramic-glass

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Endocrown restorations for extensively damaged posterior teeth: clinical performance of three cases

  • Tzimas, Konstantinos;Tsiafitsa, Maria;Gerasimou, Paris;Tsitrou, Effrosyni
    • Restorative Dentistry and Endodontics
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    • v.43 no.4
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    • pp.38.1-38.9
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    • 2018
  • The restoration of endodontically treated teeth (ETT) with more than one cusp missing and thin remaining walls is challenging for the general practitioner. The use of posts combined with full coverage restorations is a well-established approach, yet not following the minimal invasive principles of adhesive dentistry. Endocrowns are indirect monoblock restorations that use the pulp chamber of the ETT for retention. In this study the fabrication of 4 endocrowns and their clinical performance will be discussed. Two clinical cases include computer-aided design/computer-aided manufacturing manufactured molar endocrowns (one feldspathic ceramic and one hybrid composite-ceramic restoration) and the other two are dental laboratory manufactured resin composite premolar endocrown restorations. The modified United States Public Health Service criteria were used to assess the clinical behavior of the restorations at different follow up periods. Endocrown restorations present a satisfactory clinical alternative, either by the use of resin composite or glass ceramic and hybrid materials. Specific guidelines with minimal alterations should be followed for an endocrown restoration to be successful. Due to limited evidence regarding the long term evaluation of this restorative technique, a careful selection of cases should be applied.

회원사 탐방 - 신기술 개발로 다져진 작지만 강한 기업

  • Yun, Gyeong-Seon
    • The Optical Journal
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    • s.138
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    • pp.26-28
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    • 2012
  • (주)모노클(대표 이강수 www.monocle.co.kr)은 LCD, PDP, OLED 제조공정에서 필요로 하는 광학 Stage의 국산화와 가공기술개발에 앞장서 왔다. 현재 정밀 Quartz 및 Ceramic가공 기술을 바탕으로 Lens, Prism, Mirror & Filter Stage Glass, Micro & Macro Optical Parts, Optical Systems 등을 주력으로 생산해 오고 있다. 작은 중소기업이지만 (주)모노클이 세계시장에서 경쟁할 수 있는 제품을 생산하며 큰 역량을 발휘할 수 있었던 원동력은 꾸준히 연구개발에 투자하여 기술집약적 토대를 만들었기 때문이다.

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A dielectric constant measurement method of unprepared samples (비가공 물질의 유전율 측정 방법)

  • Lee, Won-Hui;Park, Wee-Sang
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.343-344
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    • 2008
  • A measurement method of the dielectric constant of materials whose standard sample is not prepared easily is proposed. The unprepared sample of the material is placed in a cavity, and the resonant frequency is measured. A commercial software simulates the same sample and the cavity leading to find the correct dielectric constant. The measured samples include a ceramic, a forced glass, and a powdered enamel.

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A Study on the Characteristics of Ultra-Precision Grinding far Sapphires (사파이어의 초정밀 연삭 특성 연구)

  • 김우순;김동현;난바의치
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.422-427
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    • 2003
  • Sapphire have been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing Process.

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Design and Simulation of DC/DC Converter for PCS Handset (PCS 단말기용 DC/DC 컨버터의 회로설계 및 시뮬레이션)

  • 김동욱;조신희;김남영;장동석;구기덕
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.739-742
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    • 1999
  • This study is to increase capability of the DC/DC converter (for PCS) in miniaturizing, stabilizing by locating an inductor with the structure of multi layer on to the glass/ceramic circuit board. When the DC/DC converter is stimulated. the characteristic operation of PWM switching circuit, losses. output power to input power, stability, efficiency and interfaces inside of control circuit and convener circuit are to be distinguished. The process would make it able to develop the techniques of designing and manufacturing of the converter of next generation.

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Development of KrF Excimer Laser with surface discharge preionization (표면예비전리 방식을 사용한 KrF 엑사이머 레이저의 개발)

  • Park, Hong-Jin;Lee, Choo-Hie
    • Proceedings of the KIEE Conference
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    • 1990.07a
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    • pp.462-464
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    • 1990
  • We report the development of a surface discharge preionized KrF discharge Laser with a new type of high-brightness Corona preionizer using a segmented columnar $BaTiO_3$ dielectric. This Laser characteristic was higher value than that obtained with the conventional corona preionizer using a glass, $Al_2O_3ceramic$, Kapton film, or a Teflon insulator.

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