OBJECTIVE To determine streptococcal adhesion forces with composite resins with different surface roughness. METHODS Polishing and grinding were applied to obtain smooth (roughness 20 nm), moderately rough (150 nm) and rough (350 nm) surfaces of two orthodontic, light-cured composites. Adhesion forces between Streptococcus sanguinis and Streptococcus mutans and the composite surfaces were mea...

Hemp fibers–reinforced unsaturated polyester (UP) composites were prepared by hand lay-out compression molding. Hemp fibers were treated with isocyanatoethyl methacrylate (IEM), using dibutyltin dilaurate as a catalyst. The results indicated that fiber treatment significantly increased tensile strength, flexural strength, flexural modulus, and water resistance of the resulting composites, and y...

Extrusion freeform fabrication has been used to make bars of fiber-reinforced epoxidized soybean oil (ESO)/epoxy resin. Freeform fabrication methods build materials by the repetitive addition of thin layers. The mixture of epoxidized soybean oil (ESO) and epoxy resin are modified with a gelling agent to solidify the materials until curing occurs. The high strength and stiffness composites are f...

The effect of prepolymerized particle fillers on fracture toughness of four commercial composite resins was studied. The ground surface morphology was examined with a field emission scanning electron microscope. Fracture toughness was determined by using single edge notched specimens. Acoustic Emission (AE), which is the elastic wave due to the release of energy from the localized sources of ma...

In this paper we build some composite materials reinforced with needles from fir trees. order to the samples, have firstly created strips in way: put pines, continuously, on a sheet of where apply thin layer resin (we used epoxy and polyester ones). We made 10 glued them together by using same synthetic resins (epoxy polyester). end obtained composites trees sheet, matrix is resins. From plate,...

background and aims. effect of surface treatments on repair bond strength of aged composite resins might be different due to their dissimilar fillers. the aim was to evaluate the effect of different surface treatments on repair micro-shear bond strength (µsbs) of silica- (spectrum tph) and zirconia-filled (filtek z250) composite resins. materials and methods. twenty-seven composite resin blocks...

AIMS AND OBJECTIVES To evaluate and compare the effect of fiber reinforcement on the dimensional changes of heat-cured poly (methyl methacrylate) resin after processing and immersion in water. MATERIALS AND METHODS Three different heat-cure resins were selected for the present study: (1) Nonreinforced heat-cure methyl methacrylate resin, (2) High Impact heat-cured methyl methacrylate resin an...

objective: the aim of this study was to evaluate the effect of concepsis (a chlorhexidine gluconate based cavity disinfectant) application on composite restorations micro leakage, using two adhesive systems: excite and adhese. materials and methods: in this interventional experimental study, class v cavities were prepared on buccal surfaces of seventy-two extracted bovine incisors. the specimen...