Aim Comparative evaluation of the fracture resistance of maxillary premolar teeth restored with two high-viscosity bulk-fill composites and incrementally placed composite. Materials and Methods Seventy-five freshly extracted maxillary premolar teeth were selected. Fifteen specimens served as positive control (Group 1). Mesio-occluso-distal cavity preparation was prepared on the rest of the sp...

graphene nanostructures were synthesized by hummer method. 1, 3, 5 and 7 wt% of graphene nanostructures were suspended in certain amount of acetone on a mechanical stirrer and stirred then added to epoxy resin. after 4 hours, solution and graphene platelets (gps) were prepared. nanostructures were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem ), fourier transform i...

in this paper, synthesized (raw) multi-walled carbon nanotube (rmwcnts) surfaces were modified with chitosan and β-cyclodextrin using chen’s soft cutting technique. raw and surface modified multi-walled carbon nanotubes were observed by transmission electron microscope (tem). the results showed that chitosan and β-cyclodextrin could attach to the outer surface of nanotubes, wrapping the nanotub...

Electrostrictive materials are promising for mechanical energy harvesting applications because of their high power density, low cost and scalability. In this paper, strain sensitive nanocomposite materials based on reduced graphene (rGO) and PDMS are used for energy harvesting; they are characterized by a high electrostrictive coefficient (2.4×10 -15 m 2 /V 2 ) and a giant dielectric constant (...

This study was inspired by the unique multi-scale and multi-level 'brick-and-mortar' (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Followi...

Hydrogels sensitive to electric current are usually made of polyelectrolytes and undergo erosion, swelling, de-swelling or bending in the presence of an applied electric field. The electrical conductivity of many polymeric materials used for the fabrication of biomedical devices is not high enough to achieve an effective modulation of the functional properties, and thus, the incorporation of co...

OBJECTIVES This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. MATERIALS AND METHODS Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million lo...

Unusually active and sinter-resistant nanocomposite materials were synthesized by combining the high reactivity of nanosized noble metal particles with the excellent hightemperature stability of hexa-aluminates through a simple one-step microemulsion-templated sol-gel synthesis. The novel nanocomposite catalysts were characterized by TEM, XRD, DTA and BET measurements after calcination at tempe...

OBJECTIVES The aim of this study was to evaluate and compare the load-bearing capacity of fractured incisal edge of maxillary permanent central incisors restored with a nanocomposite and a glass fiber-reinforced nanocomposite. MATERIALS AND METHODS Thirty-six extracted sound maxillary central incisors randomly divided in three groups were used for the present study. Group I (control) containe...