Carmem Silvia Costa Pfeifer

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Different monomer structures lead to different physical and mechanical properties for both the monomers and the polymers. The objective of this study was to determine the influence of the bisphenylglycidyl dimethacrylate (BisGMA) concentration (33, 50 or 66 mol%) and the co-monomer content [triethylene glycol dimethacrylate (TEGDMA), ethoxylated bisphenol-A(More)
The organic phase of resin composites is constituted by dimethacrylate resins, the most common monomers being the bisphenol A diglycidildimethacrylate (BisGMA), its ethoxylated version (BisEMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA). This study compared the homopolymers formed from the monomers used in restorative(More)
Optical properties of composite restoratives, both cured and uncured, are of obvious importance in a procedure reliant on photoactivation, since they may affect light transmission and therefore materials conversion upon which mechanical properties and ultimate clinical performance are dependent. The objective of the present study was to evaluate(More)
OBJECTIVES To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD would produce less Rpmax and yellowing than CQ alone(More)
OBJECTIVE This study determined the volumetric shrinkage, degree of conversion, sorption, solubility, and flexure properties (before and after aging) of commercial dental composites identified as "low shrinkage". METHODS Six Bis-GMA-based composites (Point 4, ELS, Filtek Supreme, Aelite LS Posterior, Filtek Z250 and Heliomolar), a silorane-based (Filtek(More)
OBJECTIVES Verify the influence of curing methods on contraction stress, stress rate, and degree of conversion (DC) of a restorative composite and on bond strength of composite restoratives. METHODS For the stress test, composite (0.84 mm thick) was applied between two 5-mm diameter glass rods, mounted in a servohydraulic machine. Stress rate was taken by(More)
OBJECTIVES This study demonstrates the effects of nano-scale prepolymer particles as additives to model dental monomer and composite formulations. METHODS Discrete nanogel particles were prepared by solution photopolymerization of isobornyl methacrylate and urethane dimethacrylate in the presence of a chain transfer agent, which also provided a means to(More)
OBJECTIVES The objective of this study was to verify the influence of curing methods on contraction stress, stress rate and degree of conversion (DC) of a restorative composite at two C-factor levels. METHODS For the stress test, composite was applied between two for 15 min from diameter glass rods mounted in a servohydraulic machine, and stress was(More)
OBJECTIVES To evaluate "low-shrink" composites in terms of polymerization kinetics, stress development and mechanical properties. METHODS "Low-shrink" materials (Kalore/KAL, N'Durance/NDUR, and Filtek P90/P90) and one control (Esthet X HD/EHD) were tested. Polymerization stress (PS) was measured using the Instron 5565 tensometer. Volumetric shrinkage (VS)(More)
OBJECTIVES A simple optical method for measuring polymerization shrinkage of dental composites is compared with an established dilatometer. METHODS Five restorative composites were used to test the methods: Filtek Supreme Ultra (3M ESPE), Filtek LS (3M ESPE), Premise (Kerr), Gradia Direct (GC), and GC Kalore (GC). Uncured composites were attached to(More)