The aim of this study was to compare the shrinkage stress of composite resins by three methods. In the first method, composites were inserted between two stainless steel plates. One of the plates was connected to a 20 kgf load cell of a universal testing machine (EMIC-DL-500). In the second method, disk-shaped cavities were prepared in 2-mm-thick Teflon molds and filled with the different compo...

The aim of this study was to evaluate the polymerization shrinkage and shrinkage stress of composites polymerized with a LED and a quartz tungsten halogen (QTH) light sources. The LED was used in a conventional mode (CM) and the QTH was used in both conventional and pulse-delay modes (PD). The composite resins used were Z100, A110, SureFil and Bisfil 2B (chemical-cured). Composite deformation u...

Heat of polymerization of Bis-GMA-TEDMA monomer mixtures, corresponding to the conceivable constituents of composite resins, was evaluated from the area of exothermic peak in DSC curves, and also the conversions of polymerization were calculated from the ratio of the heat of polymerization for each monomer mixture to an assumed one at 100% conversion. The effects of composition of monomers and ...

The purpose of this study was to evaluate the flexural strength, flexural modulus, modulus of resilience, and water sorption of four flowable light-cured composite resins (FCRs). Results were then compared with four conventional composite resins (CCRs) and a minifilled hybrid light-cured composite resin, which served as a control. Twenty specimens were flexural tested immediately after curing, ...

The composite fermion (CF) model of the quantum Hall effect which gives the correct series of charges is based on attachment of flux quanta to the electron. The construction of the series of charges leads to a field expression which requires that flux quanta are attached to the electron. The series based on the experimental data is correct but the field deduced from such a series is found to be...

OBJECTIVE This study compared the effect of water sorption on the extent of marginal gap reduction in a compomer (Dyract AP, Dentsply) and a composite (Spectrum, Dentsply) over a 12-week storage period. MATERIALS AND METHODS Artificial gaps were created in 40 borosilicate glass cylinders, each 5mm deep and with an internal diameter of 5.5mm. Half of the internal bonding surface of each cylind...

This in vitro study was undertaken to evaluate the caries-preventive effect of three orthodontic band cements (a dual-curing resinmodified glass ionomer cement [RMGIC] and two light-curing polyacid-modified composite resin [compomer] cements) in terms of fluoride release, retentiveness, and microleakage after thermocycling. The RMGIC (Ortholy Band Paste [GC Ortholy, Inc., Tokyo, Japan]) showed ...

Simon et al suggest that composite fermions (CF) must be replaced by composite bosons (CB) and “111” state is a boson state. However, we find that such a transition in real GaAs is not possible and the CF state can not become a boson. Simon et al suggest that the total number of CFs and CBs is conserved. However, we find that the number of quasiparticles need not be conserved. Similarly, Simon ...

The use of dental acrylics and composite resins in veterinary dentistry has become widespread. However their use is not without potential complications. All acrylics and composite resins produce an exothermic reaction during the polymerization process. The aim of the current study was to evaluate thermal conduction during the polymerization reaction of each material to offer clinical guidelines...

The study verified the bond strength in simulated dental restorations of silorane- or methacrylate-based composites repaired with methacrylate-based composite. Methacrylate- (P60) or silorane-based (P90) composites were used associated with adhesive (Adper Single Bond 2). Twenty-four hemi-hourglass-shaped samples were repaired with each composite (n=12). Samples were divided according to groups...