OBJECTIVES Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. MATERIALS AND METHODS DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were plac...

We develop a phenomenological description of the nu=5/2 quantum Hall state in which the Halperin-Lee-Read theory of the half-filled Landau level is combined with a p-wave pairing interaction between composite fermions (CFs). The electromagnetic response functions for the resulting mean-field superconducting state of the CFs are calculated and used in an RPA calculation of the q and omega depend...

Unsaturated polyester and epoxy vinyl ester resins have broad utility in composite applications. Today’s commercially available premium thermal performance vinyl ester resins are derived from novolac epoxies and methacrylic acid. These products combine low viscosity with shelf stable, yet fast curing properties, and enable fabricators to manufacture composite parts with rapid throughput for dem...

STATEMENT OF PROBLEM Flexural strength, hardness, surface roughness, discoloration, and abrasion resistance are important properties of veneering composite resins. Recently introduced veneering resins are purported to have enhanced mechanical properties due to their composition, but their long-term durability is not known. PURPOSE The purpose of this study was to test the impact of aging on 3...

In this paper we build some composite materials reinforced with corn leaves. order to the samples, have firstly created strips in way: put leaves, continuously, on a sheet of where apply layer resin (we used epoxy and polyester ones). We waited for polymerization 48 hours, recommended by producer. leaves layers director tensile test (because will samples tensile). made 10 glued them together us...

The purpose of this study was to examine the effects of LEDs on the polymerization of dental composite resins. Three composite resins and two LED units were used to evaluate the latter's effects on microhardness and temperature rise. In particular, two composite resins contained a coinitiator in addition to camphorquinone (CQ). The emission peak of the tested LEDs matched well with the absorpti...

Hardness of both the top and bottom surfaces were determined for five different composite resins varying the thickness and exposure time to light. Specimens of the five different composite resins (Durafill®, Visio-Dispers ®, Prisma-Fil®, Estilux®, and Visio-Fil ®) were prepared in brass rings with thicknesses of 1.5, 2.0, and 2.5 ram. A Barcol Hardness Number (BHN) of the top or bottom surfaces...

Glass fiber reinforced polymer composites are one of the most widely used composite materials. The addition of Coal ash to polymer matrix dramatically increases the overall mechanical strength of the composite material as compared to the polymer composite. In view of this, a method is proposed for mixing coal ash powder (size 52-75 μm) into resin and Ash reinforced polymer composites are fabric...

background: despite the growing tendency toward tooth-colored restorations in dentistry, polymerization shrinkage and subsequent marginal microleakage remains a problem. the aim of this in vitro study was to compare microleakage between silorane-based and methacrylate-based composite resins at different time intervals and with different restorative techniques. materials and methods: in this in ...

background and aims. polymerization efficacy affects the properties and performance of composite resin restorations. the purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using fourier transformation infrared (ft-ir) spectroscopy and vicke...