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“Purpose: The effect of dental fabrication procedures

of zirconia monolithic restorations and changes in properties during low-temperature exposure in the oral environment is not completely understood. The purpose of this study was to investigate the effect of procedures for fabrication of dental restorations by low-temperature simulation and relative changes of flexural strength, see more nanoindentation hardness, Young’s modulus, surface roughness, and structural stability of yttria-stabilized zirconia. Materials and Methods: A total of 64 zirconia specimens were prepared to simulate dental practice. The specimens were divided into the control group and the accelerated aging group. The simulated group followed the same procedure as the control group except for the aging treatment. Atomic force microscopy selleck inhibitor was used to measure surface roughness. The degree of tetragonal-to-monoclinic transformation was determined using X-ray diffraction. Nanoindentation

hardness and modulus measurements were carried out on the surface of the zirconia specimens using a nanoindenter XP/G200 system. The yttria levels for nonaged and aged specimens were measured using energy dispersive spectroscopy. Flexural strength was determined using the piston-on-three-ball test. The t-test was used to determine statistical significance. Results: Means and standard deviations were calculated using all observations for each condition and evaluated using a group t-test (p < 0.05). The LTD treatment resulted in increased surface roughness (from 12.23

nm to 21.56 nm for Ra and 15.06 nm to 27.45 nm for RMS) and monoclinic phase fractions (from 2% to 21%), with a concomitant decrease in hardness (from 16.56 GPa to 15.14 GPa) and modulus (from 275.68 GPa to 256.56 GPa). Yttria content (from 4.43% to 4.46%) and flexural strength (from 586 MPa to 578 MPa) were not significantly altered, supporting longer term in vivo function without biomechanical fracture. Conclusion: The LTD treatment induced the tetragonal-to-monoclinic transformation with surface roughening in zirconia prepared using dental procedures. “
“Purpose: Carbon nanotubes are used in dentistry, although there are no adequate scientific data to support their use in acrylic resins. The polymerization click here shrinkage that occurs with polymethylmethacrylate (PMMA) resins is well known. This study compared the polymerization shrinkage of denture base acrylic resin with and without micro-additions of carbon nanotubes. Materials and Methods: Two materials were used, PMMA resin and multiwalled carbon nanotubes. Four groups were established of 10 specimens each according to the weight percent of carbon nanotubes dispersed and disintegrated in the monomer: group I (0.5% of carbon nanotubes in monomer), II (0.25%), III (0.125%), and IV (control group, 0%).