Evaluation of microhardness, surface roughness, and wear behavior of different types of resin composites polymerized with two different light sources

Abstract

The microhardness, surface roughness and wear resistance of different types of resin composites, polymerized by a Quartz Tungsten Halogen (QTH) or Light Emitting Diode (LED) light curing units (LCU) were evaluated in this in vitro study. Cylindrical blocks were prepared from composites (8 mm in diameter, and 2 mm in thickness) and polymerized by a LED or a QTH LCU. Vickers hardness was measured on the top and bottom surfaces of the specimens. Surface roughness was measured with a surface profilometer on the top of the specimens. For the wear test, specimens were tested in a conventional pin-on-disc tribology machine under 15 N loads. The statistical analyses were performed by one-way analysis of variance (ANOVA) and t-tests, including the Bonferroni correction. Nanocomposite material Clearfil Majesty Posterior showed the highest hardness values in all polymerization types at the top and bottom surfaces (p < 0.05). Microhybrid Clearfil APX and hybrid Quixfil composites demonstrated the greatest surface roughness. Wear resistance of Clearfil Majesty Posterior was found to be the highest among the other tested resin composites. The results indicated that Clearfil Majesty Posterior demonstrated higher microhardness, less surface roughness, and higher wear resistance when compared with the other tested materials for both polymerization types.

Wavelength of Experimental LEDS: Hardness, Elastic Modulus, Degree of Conversion and Temperature Rise of a Microhybrid Composite

“…The lowest hardness and elastic modulus values were found on composite's bottom surface. Previous studies had also found similar results 12,21,24,25 . During photopolymerization, there is a considerable reduction of irradiance in deeper regions through the bulk of the composite, due to absorption and scattering of light by the resin matrix and particles filler 25 .…”

“…Previous studies had also found similar results 12,21,24,25 . During photopolymerization, there is a considerable reduction of irradiance in deeper regions through the bulk of the composite, due to absorption and scattering of light by the resin matrix and particles filler 25 . This decrease in light results in reduced photons emission, interfering in the material's curing, and resulting in lower values for the mechanical properties tested.…”

Viscoelastic properties of low-shrinking composite resins compared to packable composite resins

“…CM has very high filler content (82 vol%) which reduces the amount of available resin matrix in the resin composite and leads to lower volumetric shrinkage 16,17) . Its high filler content explains the high moduli values that were obtained, which is probably the reason for its high wear resistance found in one study 18) and possibly other mechanical properties. However, despite its low shrinkage this material was found to show similar marginal adaptation to materials that shrink more 19) .…”

Effect of different post-cure polymerization treatment on composite resin hardness

“…These average values were considered as dependent variable for statistical analysis. The independent variables "resin type" and "polymerization method" were compared with one another using the one-way ANOVA variance analysis with identification of individual significance held by Tukey test, considering statistically significant difference when p≤0,05 [18][19] .…”

“…The hardness is directly related to wear resistance, as evidenced in the literature, establishing a correlation where the higher the hardness, the lower the surface wear of the composite resin 18,[29][30] . Wear resistance is one of the main properties of a composite and the capability of the material to be suitable for use in areas of masticatory effort depends on it.…”