## Abstract It was the aim of the present experiments to evaluate the fluoride leaching of four compomers and one resinβmodified glassβionomer cement (gic) into aqueous media over a 1βyear period. Various extraction/equilibrium solutions were applied to simulate important intraoral parameters. Spec
The effect of temperature on viscoelastic properties of glass ionomer cements and compomers
β Scribed by M. Helvatjoglu-Antoniades; Y. Papadogiannis; R. S. Lakes; G. Palaghias; D. Papadogiannis
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 146 KB
- Volume
- 80B
- Category
- Article
- ISSN
- 1552-4973
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β¦ Synopsis
Abstract
The objective of this study was to determine the viscoelastic properties of different types of glass ionomer cements (GICs) and compomers under varying temperature conditions found in the mouth. The materials tested were a conventional GIC (Aqua Ionofil U), a resin modified GIC (Fuji II LC), a highly viscous GIC (Voco Ionofil Molar), and two polyacid modified composite resins/compomers (Glasiosite and Dyract Flow). Six groups of four specimens were prepared from each material. One group was stored dry for 24 h and was subsequently tested dry at 21Β°C. Each of the remaining five groups was stored for 24 h in distilled water at the temperatures 21, 30.5, 37, 43.5, and 50Β°C, respectively, and was subsequently tested at that temperature. Shear storage modulus and loss tangent were determined by conducting dynamic torsional loading. Static shear moduli were determined by applying a constant torque (below the proportional limit of the materials) for 10 s and recording the angular deformation of the specimens. Data were analyzed by ANOVA and Duncan's test (Ξ±= 0.05). It was found that the viscoelastic properties varied significantly (p < 0.05) across the different materials. The compomer Glasiosite, with the highest filler content, and the highly viscous GIC Voco Ionofil Molar exhibited the highest elastic moduli and lowest loss tangents. Viscoelastic properties varied also significantly (p < 0.05) with temperature levels, but changes in the tested region were not indicative of a glass transition. Dynamic shear storage moduli were highly correlated to the static ones. Storage in water lowered the values of elastic moduli. Β© 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
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## Abstract __Background:__ Ultrasonic excitation (US) was applied to glass ionomer cement (GIC) during early set time to increase the advantageous properties of this material. __Purpose:__ The aim of this in vitro study was to assess the inner porosity of GIC after US. __Study design:__ A total of
It has been shown that preheating the femoral stem prior to insertion minimizes interfacial porosity at the stem-cement interface. In this study, the effects of methylmethacrylate monomer temperature prior to mixing on the properties of stem-cement interface and cement polymerization were evaluated