The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
A Arikan - One of the best experts on this subject based on the ideXlab platform.
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effect of 180 days of water storage on the transverse strength of Acetal Resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal Resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that Acetal Resin has superior physical properties when compared to conventional denture base acrylic Resins. Limited information is available about transverse strengths of Acetal Resin. The purpose of this investigation was to compare transverse strengths of pink and white Acetal Resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) Resin in increasing durations of water storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each Resin were prepared; five specimens of each Resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of water storage in distilled water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink Acetal Resin could not be calculated in this study, as white and pink Acetal Resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of Acetal Resin was found to be within the ISO specification limits. As the water storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink Acetal Resin showed significant increase in deflection as the water storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal Resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal Resin showed significant increase in deflection as the water storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
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an in vitro comparison of retentive force and deformation of Acetal Resin and cobalt chromium clasps
Journal of Prosthetic Dentistry, 2005Co-Authors: T Arda, A ArikanAbstract:Statement of problem The use of metal clasps on anterior teeth may cause esthetic problems. Recently, Acetal Resins have been used as an alternative tooth-colored denture clasp material to improve esthetics. However, there are few studies to support Acetal Resin use. Purpose The purpose of this in vitro study was to compare the retentive force and deformation of Acetal Resin and cobalt-chromium clasps after 36 months of simulated clinical use. Material and methods Forty clasps each of Acetal Resin (1.2 or 2.0 mm thick) and cobalt-chromium (Dentorium)(1.2 mm thick) were fabricated using half-round standard prefabricated clasp patterns. The groups were further subdivided (n = 10) into the type of tooth (premolar or molar metal model) and undercut (0.25 mm or 0.50 mm). The retentive force of the clasps was measured in distilled water by a specially designed insertion-removal testing apparatus with intervals corresponding to 0, 6, 12, 18, 24, 30, and 36 months of simulated clinical use of a removable partial denture. The distance between the clasp tips (mm) was measured with a microscope before and after the insertion-removal testing procedure. Comparison of the mean values of the retentive force (gram force) of the clasps and the distance (mm) between the clasp tips was conducted with 3-way analysis of variance and a Least Significant Difference (LSD) multiple range test (α=.05). Results The mean values of tensile load required to dislodge Acetal Resin clasps with 1.2-mm thickness (111.6 g or 0.11 N) and with 2.0-mm thickness (178.4 g or 1.75 N) was significantly lower than that to dislodge Co-Cr clasps (694.1 g or 6.81 N) ( P P P Conclusion Within the limitations of this study, the results suggest that both thicknesses of Acetal Resin clasps evaluated required less force for insertion and removal than Co-Cr clasps over a simulated 36-month period.
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An in vitro investigation of water sorption and solubility of two Acetal denture base materials.
The European journal of prosthodontics and restorative dentistry, 2005Co-Authors: A Arikan, T Arda, Yasemin Özkan, B AkalinAbstract:Acetal Resins have been used as an alternative denture base and clasp material recently. The aim of this study was to compare water sorption and water solubility of pink and white Acetal Resins as compared to a heat-polymerized polymethyl methacrylate Resin (PMMA). The tests were performed in accordance with International Standards Organization specification No: 1567. Pink Acetal Resin showed significantly lower water sorption than heat-polymerized acrylic Resin and white Acetal Resin. PMMA showed significantly higher solubility than pink and white Acetal Resin. Water sorption and solubility of PMMA, pink and white Acetal Resins were within the ISO specification limit.
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A study to assess the colour stability of Acetal Resins subjected to thermocycling
Eur J Prosthodont Restor Dent, 2005Co-Authors: Yasar Ozkan, B Akalin, A Arikan, T ArdaAbstract:The purpose of this study was to compare colour stability of pink and white Acetal Resin with one conventional poly (methylmethacrylate) Resin. Five specimen disks 50 +/- 0.1 mm in diameter and approximately 1.0 mm thick were prepared from each material. The discs were hydrated for a period of 30 days in distilled water and were then desiccated to a constant weight. Total of fifteen specimens were thermocycled for 100 and 300 hours (4000-12000 cycle) between water baths of 5-55 degrees C. Changes from baseline colour readings were recorded at each interval. Data were analysed with descriptive statistic, repeated measured analysis of variance and single factor analysis of variance. The colour changes for all materials at 100 hours were in the categories of slight, based upon the National Bureau of Standard System (NBS) for expressing colour difference. At 300 hours, the colour changes of materials were significantly different (p = 0.0001). All the materials tested showed clinically acceptable discolouration values.
Marek Chmielewski - One of the best experts on this subject based on the ideXlab platform.
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a new Acetal Resin valuable for the solid phase synthesis of 1 oxacephamsvia a cyclization cleavage step
Tetrahedron Letters, 1999Co-Authors: Bartlomiej Furman, Rene Thu Rmer, Zbigniew Kaluza, Wolfgang Voelter, Marek ChmielewskiAbstract:Abstract Synthesis of benzyloxybenzaldehyde dimethyl Acetal Resin7 and its usefulness for immobilising 1,3-diols is described. The regioselective cleavage with DIBAL-H in CH2Cl2 of the Resin-bound Acetals10 and11 provided the polymer-bound alcohols12 and13 which were used as starting materials in the solid-phase synthesis of 1-dethia-1-oxacephams.
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A new Acetal Resin valuable for the solid-phase synthesis of 1-oxacephamsvia a cyclization/cleavage step
Tetrahedron Letters, 1999Co-Authors: Bartłomiej Furman, Wolfgang Voelter, Rene´ Thu¨rmer, Zbigniew Kałuża, Marek ChmielewskiAbstract:Abstract Synthesis of benzyloxybenzaldehyde dimethyl Acetal Resin7 and its usefulness for immobilising 1,3-diols is described. The regioselective cleavage with DIBAL-H in CH2Cl2 of the Resin-bound Acetals10 and11 provided the polymer-bound alcohols12 and13 which were used as starting materials in the solid-phase synthesis of 1-dethia-1-oxacephams.
T Arda - One of the best experts on this subject based on the ideXlab platform.
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effect of 180 days of water storage on the transverse strength of Acetal Resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal Resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that Acetal Resin has superior physical properties when compared to conventional denture base acrylic Resins. Limited information is available about transverse strengths of Acetal Resin. The purpose of this investigation was to compare transverse strengths of pink and white Acetal Resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) Resin in increasing durations of water storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each Resin were prepared; five specimens of each Resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of water storage in distilled water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink Acetal Resin could not be calculated in this study, as white and pink Acetal Resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of Acetal Resin was found to be within the ISO specification limits. As the water storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink Acetal Resin showed significant increase in deflection as the water storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal Resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal Resin showed significant increase in deflection as the water storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
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an in vitro comparison of retentive force and deformation of Acetal Resin and cobalt chromium clasps
Journal of Prosthetic Dentistry, 2005Co-Authors: T Arda, A ArikanAbstract:Statement of problem The use of metal clasps on anterior teeth may cause esthetic problems. Recently, Acetal Resins have been used as an alternative tooth-colored denture clasp material to improve esthetics. However, there are few studies to support Acetal Resin use. Purpose The purpose of this in vitro study was to compare the retentive force and deformation of Acetal Resin and cobalt-chromium clasps after 36 months of simulated clinical use. Material and methods Forty clasps each of Acetal Resin (1.2 or 2.0 mm thick) and cobalt-chromium (Dentorium)(1.2 mm thick) were fabricated using half-round standard prefabricated clasp patterns. The groups were further subdivided (n = 10) into the type of tooth (premolar or molar metal model) and undercut (0.25 mm or 0.50 mm). The retentive force of the clasps was measured in distilled water by a specially designed insertion-removal testing apparatus with intervals corresponding to 0, 6, 12, 18, 24, 30, and 36 months of simulated clinical use of a removable partial denture. The distance between the clasp tips (mm) was measured with a microscope before and after the insertion-removal testing procedure. Comparison of the mean values of the retentive force (gram force) of the clasps and the distance (mm) between the clasp tips was conducted with 3-way analysis of variance and a Least Significant Difference (LSD) multiple range test (α=.05). Results The mean values of tensile load required to dislodge Acetal Resin clasps with 1.2-mm thickness (111.6 g or 0.11 N) and with 2.0-mm thickness (178.4 g or 1.75 N) was significantly lower than that to dislodge Co-Cr clasps (694.1 g or 6.81 N) ( P P P Conclusion Within the limitations of this study, the results suggest that both thicknesses of Acetal Resin clasps evaluated required less force for insertion and removal than Co-Cr clasps over a simulated 36-month period.
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An in vitro investigation of water sorption and solubility of two Acetal denture base materials.
The European journal of prosthodontics and restorative dentistry, 2005Co-Authors: A Arikan, T Arda, Yasemin Özkan, B AkalinAbstract:Acetal Resins have been used as an alternative denture base and clasp material recently. The aim of this study was to compare water sorption and water solubility of pink and white Acetal Resins as compared to a heat-polymerized polymethyl methacrylate Resin (PMMA). The tests were performed in accordance with International Standards Organization specification No: 1567. Pink Acetal Resin showed significantly lower water sorption than heat-polymerized acrylic Resin and white Acetal Resin. PMMA showed significantly higher solubility than pink and white Acetal Resin. Water sorption and solubility of PMMA, pink and white Acetal Resins were within the ISO specification limit.
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A study to assess the colour stability of Acetal Resins subjected to thermocycling
Eur J Prosthodont Restor Dent, 2005Co-Authors: Yasar Ozkan, B Akalin, A Arikan, T ArdaAbstract:The purpose of this study was to compare colour stability of pink and white Acetal Resin with one conventional poly (methylmethacrylate) Resin. Five specimen disks 50 +/- 0.1 mm in diameter and approximately 1.0 mm thick were prepared from each material. The discs were hydrated for a period of 30 days in distilled water and were then desiccated to a constant weight. Total of fifteen specimens were thermocycled for 100 and 300 hours (4000-12000 cycle) between water baths of 5-55 degrees C. Changes from baseline colour readings were recorded at each interval. Data were analysed with descriptive statistic, repeated measured analysis of variance and single factor analysis of variance. The colour changes for all materials at 100 hours were in the categories of slight, based upon the National Bureau of Standard System (NBS) for expressing colour difference. At 300 hours, the colour changes of materials were significantly different (p = 0.0001). All the materials tested showed clinically acceptable discolouration values.
Muhammad Zubair - One of the best experts on this subject based on the ideXlab platform.
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APCCAS - Hand-held non-invasive NIR device for early stage breast cancer pre-screening
2019 IEEE Asia Pacific Conference on Circuits and Systems (APCCAS), 2019Co-Authors: Muhammad A. Hussain, Muhammad U. Farooq, Muhammad Q. Mehmood, Muhammad ZubairAbstract:We present a hand-held, low-cost, non-invasive and non-ionizing near-infrared (NIR) light-based pre-screening devices for early stage breast cancer. The pre-screening of breast cancer in women at risk can improve the prognosis of patients, and such a solution should complement the existing diagnostic approaches. Our design is based on the principle of amplitude cancellation of two anti-phase NIR light-emitting diodes (LEDs) operated at a wavelength of 840nm placed at a fixed distance from a photodetector in the middle. The device has been tested on breast phantom made of Acetal Resin Rod. The design functionality has been achieved from implemented prototype and has been verified by several experiments resulting in detection of a non-homogenous object inside the phantom. This proposed design can be further improved by integration with efficient probe-based algorithm, which will show the presence of abnormalities in the human breast in an automated procedure. This device can provide a practical, low-cost solution for massive breast-cancer pre-screening campaigns, especially in developing countries.
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Hand-held non-invasive NIR device for early stage breast cancer pre-screening
2019 IEEE Asia Pacific Conference on Circuits and Systems (APCCAS), 2019Co-Authors: Muhammad A. Hussain, Muhammad U. Farooq, Muhammad Q. Mehmood, Muhammad ZubairAbstract:We present a hand-held, low-cost, non-invasive and non-ionizing near-infrared (NIR) light-based pre-screening devices for early stage breast cancer. The pre-screening of breast cancer in women at risk can improve the prognosis of patients, and such a solution should complement the existing diagnostic approaches. Our design is based on the principle of amplitude cancellation of two anti-phase NIR light-emitting diodes (LEDs) operated at a wavelength of 840nm placed at a fixed distance from a photodetector in the middle. The device has been tested on breast phantom made of Acetal Resin Rod. The design functionality has been achieved from implemented prototype and has been verified by several experiments resulting in detection of a non-homogenous object inside the phantom. This proposed design can be further improved by integration with efficient probe-based algorithm, which will show the presence of abnormalities in the human breast in an automated procedure. This device can provide a practical, low-cost solution for massive breast-cancer pre-screening campaigns, especially in developing countries.
Yuhi Shimazumi - One of the best experts on this subject based on the ideXlab platform.
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slurry composition ceramic green sheet and layered ceramic capacitor
2012Co-Authors: Yuhi ShimazumiAbstract:[Problem] To provide a slurry composition with which the resulting ceramic green sheet has sufficient mechanical strength and shows little dimensional change during storage but there is no separation of layers early during degreasing. [Solution] A slurry composition comprises a polyvinyl Acetal Resin having a degree of polymerization between 500 and 6,000, a vinyl ester unit content between 0.01 and 30 mol%, a degree of Acetalization between 50 and 83 mol%, and a molar ratio per molecule of structural units represented by chemical formula (1) to the total amount of fully Acetalized structural units of 30% or higher; 10 to 1,000 ppm of 2-methylpropanoic acid per the polyvinyl Acetal Resin; and organic solvent.
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polyvinyl Acetal Resin slurry composition prepared therefrom ceramic green sheet and multilayer ceramic capacitor
2011Co-Authors: Yuhi ShimazumiAbstract:A slurry composition, including: a polyvinyl Acetal Resin; a ceramic powder; and an organic solvent. The polyvinyl Acetal Resin has a degree of polymerization of from 200 to 6000, a content percentage of vinylester unit of from 0.01 to 30 mol %, and a degree of Acetalization of from 55 to 83 mol %. The polyvinyl Acetal Resin has a structural unit of formula (1) in the molecule:
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polyvinyl Acetal Resin for ceramic green sheets process for production thereof slurry composition ceramic green sheets and laminted ceramic capacitor
2011Co-Authors: Yuhi Shimazumi, Seiji TanimotoAbstract:Provided is a polyvinyl Acetal Resin which ensures excellent applicability in forming a ceramic green sheet and enables the formation of a ceramic green sheet having sufficient mechanical strengths and which is only slightly dissolved in an organic solvent contained in an electroconductive paste. A polyvinyl Acetal Resin characterized by: a degree of polymerization of 3000 to 5000; a vinyl ester unit content of 4 to 23mol%; a degree of Acetalization of 60 to 80mol%; and a solution viscosity of less than 300mPa·s as determined at a solution temperature of 20°C with a Brookfield viscometer by using a 5 mass% solution prepared by dissolving the Resin in a 1:1 ethanol/toluene mixed solvent.