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Comparison of the shaping ability of novel thermally treated reciprocating instruments

  • Keskin, Cangul;Demiral, Murat;Sariyilmaz, Evren
    • Restorative Dentistry and Endodontics
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    • v.43 no.2
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    • pp.15.1-15.7
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    • 2018
  • Objectives: The present study aimed to evaluate the shaping ability of 2 thermally treated nickel-titanium reciprocating systems in simulated curved canals. Materials and Methods: Forty simulated canals were prepared to apical size 25 using Reciproc Blue R25 (VDW) and WaveOne Gold Primary (Dentsply Sirona) instruments. Standard pre- and post-preparation images were taken and superimposed. The removal of resin material was measured at 5 standard points: the canal orifice, halfway between the canal orifice and the beginning of the curve, the beginning of the curve, the apex of the curve, and the end-point of the simulated canal. The data were analysed using the independent sample t-test with a 5% significance threshold. Results: The canals in which Reciproc Blue R25 was used showed a significantly greater widening than those in which WaveOne Gold was used at 4 of the 5 measurement points (p < 0.05). The Reciproc Blue R25 instrument removed significantly more resin from the inner aspect of the curve at 2 of the 5 points and similar amounts at the remaining 3 points. At the 2 apical points, there was no significant difference between the Reciproc Blue R25 and WaveOne Gold Primary instruments. Conclusion: Both instruments respected the original canal anatomy; however, WaveOne Gold resulted in a more conservative shape with less transportation.

Intraoperative discomfort associated with the use of a rotary or reciprocating system: a prospective randomized clinical trial

  • Gomes, Aline Cristine;Soares, Adriana Jesus;Souza, Erick M;Zaia, Alexandre Augusto;Silva, Emmanuel Joao Nogueira Leal
    • Restorative Dentistry and Endodontics
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    • v.42 no.2
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    • pp.140-145
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    • 2017
  • Objectives: The aim of this randomized, controlled, prospective clinical study was to evaluate patients' intraoperative discomfort during root canal preparations in which either multi-file rotary (Mtwo) or single-file reciprocating (Reciproc) systems were used. Materials and Methods: Fifty-five adult patients, aged between 25 and 69 years old, with irreversible pulpitis or pulp necrosis participated in this study. Either the mesiobuccal or the distobuccal canals for maxillary molars and either the mesiobuccal or the mesiolingual canals for mandibular molars were randomly chosen to be instrumented with Mtwo multi-file rotary or Reciproc single-file reciprocating systems. Immediately after each canal instrumentation under anesthesia, patient discomfort was assessed using a 1 - 10 visual analog scale (VAS), ranging from 'least possible discomfort' (1) to 'greatest possible discomfort' (10). The Wilcoxon signed-rank test was used to determine significant differences at p < 0.05. Results: Little intraoperative discomfort was found in all cases. No statistically significant differences in intraoperative discomfort between the 2 systems were found (p = 0.660). Conclusions: Root canal preparation with multi-file rotary or single-file reciprocating systems had similar and minimal effects on patients' intraoperative discomfort.

AN EXPERIMENTAL STUDY ON THE SEALING EFFECT OF A FEW CAVITY LINERS UPON THE DENTINAL TUBULE (수종(數種) 와동이장재(窩洞裏裝材)의 상아질세관(象牙質細管) 폐쇄효과(閉鎖效果)에 관(関)한 실험적(實β的) 연구(硏究))

  • Son, Ho-Hyun
    • Restorative Dentistry and Endodontics
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    • v.6 no.1
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    • pp.141-147
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    • 1980
  • The sealing effect of a few cavity liners upon the dentinal tubule were studied in vitro. The materials employed in this study were Silcot (SP$\'{E}$CIALIT$\'{E}$S SEPTODONT, M.-T. GENDRAULT, Pharmacien), Hypo-Cal(Ellman Dental Mfg.Co.Inc.), Cavity Lining(De Trey), and Copaute(Harry J. Bosworth Co.). Freshly extracted human teeth were devided into 5 groups by age-under twenty, twenties, thirties, forties, and over fifty. Class V cavities were prepared routinely. The cavity walls of eight teeth of each group were lined by Silcot, Copalite, Cavity Lining, and Hypo-Cal. Remaining eight were not lined as a control. These specimens were immersed in dye solution (2 gm eosin Y to 800 cc distilled water) for 48 hours to allow maximum dye penetration into dentinal tubules. Each specimen was sectioned longitudinally including Class V cavity floor under water spray. Dye penetration into dentinal tubules were examined and following results were obtained. 1. Liners used on this study showed more or less dye penetration into dentinal tubules. But compared with the teeth without lining, the dye penetration of lined specimens were decreased. 2. Of these liners tested, Silcot was the most effective sealer upon the dentinal tubules. Copalite was the moderate sealer and Cavity Lining showed a tendency similar to Copalite. Hypo-Cal revealed the greatest dye penetration. 3. As the age was increased, the more the dye penetration into the dentinal tubules was decreased.

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Use of a capacitance voltage technique to study copper drift diffusion in low-k polyimide (C-V Technique을 이용한 low-k polyimide로의 구리의 drift diffusion 연구)

  • Choi, Yong-Ho;Lee, Heon-Yong;Kim, Jee-Gyun;Kim, Jung-Woo;Kim, Yoo-Kyuong;Park, Jin-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05c
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    • pp.137-140
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    • 2003
  • Cu+ ions drift diffusion in different dielectric materials is evaluated. The diffusion is investigated by measuring shift in the flatband voltage of capacitance/voltage measurements on Cu gate capacitors after bias temperature stressing. At a field of 1.lMV/cm and temperature $200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$ for 1H, 2H, 5H. The Cu+ ions drift rate of polyimide$(2.8{\leq}k{\leq}3.2)$ is considerably lower than thermal oxide. Also Cu+ drift rate of polyimide is similar to PECVD oxide. But, polyimide film is even more resistant to Cu drift diffusion and thermal effect than Thermal oxide, PECVD oxide: This results got a comparative reference. The important conclusion is that polyimide film is strongly dielectric material by thermal effect and Cu drift diffusion.

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The characteristic study of hybrid X-ray detector using CdTe and Zns:AgCl phosphor (CdTe 와 ZnS:AgCl phosphor를 이용한 Hybrid형 X선 검출기의 특성연구)

  • Seok, Dae-Woo;Kang, Sang-Sik;Kim, Jin-Young;Park, Ji-Koon;Mun, Chi-Woong;Nam, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05c
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    • pp.71-74
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    • 2003
  • Photoconductor for direct detection fiat-panel imager present a great materials challenge, since their requirement include high X-ray absorption, ionization and charge collection, low leakage current and large area deposition, CdTe is practical material. We report studies of detector sensitivity, That is an CdTe with $5{\mu}m$ thickness on glass. That is hybrid layer of depositting ZnS:AgCl phosphor with $100{\mu}m$ on CdTe. The leakage current of hybrid is similar to it of a-Se, but photocurrent is larger than a-Se. Both of them have high spatial resolution, but hybrid has higher sensitivity than a-Se at comparable bias voltage.

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기공(氣功)의 관점(觀點)에서 본 타액(唾液)

  • Lee Hyun-Lee;Goo Byong-Soo
    • Journal of Korean Medical Ki-Gong Academy
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    • v.3 no.2
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    • pp.87-107
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    • 1999
  • This study is about saliva from a GIGONG's point of view, it's importance, and it's funtion that recently medical world proved. And here is GIGONG training with saliva. The results were summarized as follows. 1. It is detected that saliva have function to prevent symptoms of senility and have effect of an $anti{\sim}cancer$ medically in recent years. So it is said that science proved narrowly that so called a predecessor speak of salive interms of high praise and they already experienced. 2. Similar substance to saliva exist in human body besides nature food, but human body have materials that deal with all situation to occur from every kind of environment and disease. And exactly saliva is an example of it. 3. We cannot turn back sweat, blood, tears and sperm again that is out of human body once, but we can swallow again only saliva. Therefore, we must experience training that swallow saliva to make us healthy by ourselves, and we don't have to commit a foolish act to cough up saliva at random that a predecessor speak of in terms of high praise, and to be second to JUNG(精). 4. Saliva is a kind of antibody or hormone, so I think that we need to make a study of using saliva with a GUIGONG that is an example of way to strengthen immunity of human body.

Effect of P(VDF/TrFE) Film Thickness on the Characteristics of Pyroelectric Passive Infrared Ray Sensor for Human Body Detection (P(VDF/TrFE) 필름의 두께에 따른 인체 감지형 초전형 PIR 적외선 센서의 특성)

  • Kwon, Sung-Yeol
    • Journal of Sensor Science and Technology
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    • v.20 no.2
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    • pp.114-117
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    • 2011
  • A thick 25 ${\mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated and then thin 1.6 ${\mu}m$ thickness P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated also. These thick and thin P(VDF/TrFE) film pyroelectric infrared ray sensor was mounted in TO-5 housing to detect infrared light of 5.5 ~ 14 ${\mu}m$ wavelength for human body detecting with each other. The noise output voltage of the thick P(VDF/TrFE) film pyroelectric infrared ray sensor were 380 mV and NEP(noise equivalent power) is $3.95{\times}10^{-7}$ W which is the similar value with the commercial pyroelectric infrared ray sensor using ceramic materials as a sensing material. The NEP and specific detectivity $D^*$ of the thin P(VDF/TrFE) film pyroelectric infrared ray sensor were $2.13{\times}10^{-8}$ W and $9.37{\times}106$ cm/W under emission energy of 13 ${\mu}W/cm^2$ respectively. These result caused by lower thermal diffusion coefficient of a thin 1.6 ${\mu}m$ thickness PVDF/TrFE film than the thick 25 ${\mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor.

A Study of Cultural Design Thinking Included in the Works of Shigeru-Uchida and Berner Panton (우치다시게루와 베르너팬톤의 작품에 내재된 문화적 디자인 사고)

  • Oh, Mihyun;Kim, Jong-seo
    • Journal of the Korea Furniture Society
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    • v.28 no.3
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    • pp.198-206
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    • 2017
  • In this study, analysis of the cultural effects on design expressions and comparative analysis of designers' cultural background on their expression methods were implemented. The purpose of this study is to help the professionals and learners who pursue towards cultural designs in the design field utilize this research work as reference data and academic materials, and to contribute to the development of designs in the Eastern cultures. The author compared the differences between the viewpoints depending on background, either the Eastern or the Western culture, based on the existing studies and literatures, and analyzed the relationship between the viewpoints and expressions. Also, analyses of the expression methods related with cultural viewpoints and design viewpoints were conducted, especially with analysis of works of Uchida Shigeru from the East and Berner Panton from the West. Although both of their works were produced contemporarily and expressed with similar techniques, each of the conceptual approaches to their works represents different characteristics of the cultural viewpoint. Such a finding suggests that the approach to the design process should take place in a different way based on its cultural background, and it is accordingly required to seek for a new method for cultural design process.

The Effect of Customer-to-Customer Interactions on the Preference of Fashion Purchase Environment

  • Chung, Ihn-Hee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.12
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    • pp.1497-1506
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    • 2011
  • This study identifies the effect of customer-to-customer interactions on the preference of fashion purchase environment. An empirical study surveyed male and female consumers 25 years of age and older in Daegu, Korea, in August 2011. A total of 338 responses were analyzed using descriptive statistics and chi-square analysis of SPSS 19.0. The results identified the effects of the number, gender, age, attractiveness, and taste of other customers in fashion retail settings. In addition, differences in the effect of customer-to-customer interactions according to consumer attributes were also verified. The sample of this study preferred a shopping condition of many shoppers in the store, the same gender shoppers in the store, the same aged shoppers in the store, an attractive shopper in the store, and a shopper having the same taste in the store. Female consumers showed a preference for a store environment with many shoppers and the same gender shoppers to a store of no shoppers and different gender shoppers compared to male consumers. Aged consumers and fashion-involved consumers liked to shop with more attractive persons than less attractive persons. Fashion-innovative consumers wanted to enter a store where the other customers have similar tastes.

The Response of the Burke-Schumann Flame to External Excitation with Flame Shape and Heat Release (외부 교란에 대한 Burke-Schumann 화염에서 형상과 열방출량을 통한 응답 특성 파악)

  • Kim, Taesung;Ahn, Myunggeun;Hwang, Jeongjae;Jeong, Chanyeong;Kwon, Oh Chae;Yoon, Youngbin
    • Journal of the Korean Society of Combustion
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    • v.22 no.1
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    • pp.32-38
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    • 2017
  • This paper shows the dynamics of the Burke-Schumann flame. To show flame dynamics, this paper measures the flame surface and heat release rate. The flame shape is divided into three types with forcing frequencies. When the forcing frequency is lower than 120 Hz, the upper region of flame is cut. The flame is stagnant with 220 to 280 Hz forcing frequencies. The rest conditions of forcing frequencies make the connected wave shape of flame. The heat release rate is expressed by the flame transfer function. The gain of the flame transfer function is similar with the oscillation magnitude of the flame area except for flame cutting conditions. The flame is cut because the fuel is not supplied to upper flame region.