Surface texture of four nanofilled and one hybrid composite after finishing

Abstract

This study evaluated the surface geometry of four nanocomposites and 1 hybrid composite after finishing with rigid rotary instruments. Four nanofilled composites (Premise, KerrHawe; Tetric EvoCeram, Ivoclar Vivadent; Filtek Supreme, 3M ESPE; Ceram X Duo, Dentsply) and one hybrid composite (Herculite XRV, KerrHawe) were used for the study. Sixty specimens were made of each product, 7×7 mm in size. Fifteen specimens of each composite were subjected to the following finishing procedures: a 30 μm diamond (FM1), a sequence of a 30 μm and a 20 μm diamond (FM 2) and a 30 μm diamond followed by a 12-fluted tungsten carbide finishing bur (FM 3). As a reference, 15 other specimens of each material were treated with Sof-Lex discs. Evaluation of the surfaces was done with laser-stylus profilometry. Roughness parameters were average roughness (Ra) and profile-length ratio (LR). Statistical analysis of the data was performed by two-way and one-way ANOVA and post-hoc tests by Scheffé. Additional qualitative assessment of the finished composite surfaces was done by scanning electron microscopy (SEM) at a tension of 25 kV. The composite materials and the finishing methods had a significant effect on surface roughness (p<0.001 for Ra and LR). There were significant interactions between the materials and the finishing methods (p<0.001 for Ra and LR). Compared to Herculite XRV, three of the nanocomposites were significantly smoother after finishing, according to FM 1-3 and after application of the Sof-Lex discs. Ceram X Duo and Herculite XRV had similar surface roughness in terms of Ra and LR. Compared to a single 30 urn diamond and a sequence of two diamonds (FM 2), significantly lower roughness values on all composites were achieved by using a 30 μm diamond followed by a tungsten carbide instrument (p<0.001 for Ra and LR). Ra- and LR-values after FM 3 were similar or, in some cases, even lower than surface roughness measured after application of Sof-Lex discs. Evaluation by SEM revealed that the use of a 30 μm diamond caused detrimental surface alteration on all types of composites. A remarkable number of porosities were detected on 1 of the nanofilled composites.