Effect of additional polishing methods on the physical surface properties of different nanocomposites: SEM and AFM study.

This evaluated the arrangement of filler particles in depth of nanocomposites, and surface roughness, wettability, microtopography, and micromorphology following additional polishing step. Forty samples of each composite tested [Filtek Z350XT (FZ), IPS Empress Direct (IP)] were fabricated and finished/polished/additionally polished using one of the following methods (n = 10/group): no finishing/polishing (NFP), Sof-Lex Pop-On + no additional polishing (SP), Sof-Lex Pop-On + Astropol rubber polisher (SP+A), and Sof-Lex Pop-On + felt disc with polishing paste (SP+FP). Surface roughness (Ra) and contact angles were measured using a profilometer and goniometer, respectively. Microtopography and micromorphology were evaluated using atomic force microscopy and scanning electron microscopy, respectively. Ra and contact angle data were examined by two-way analysis of variance and Tukey's test (p < .05). Organic matrix, lower and larger filler particles were disposed in depth. Mean Ra values were lowest and contact angles were smallest in the NFP group for both composite resins. SP+A and SP+FP decreased mean Ra in comparison with SP for FZ, whereas only SP+FP decreased mean Ra in comparison with SP for IP. Only SP+FP increased contact angles in comparison with SP for FZ, whereas contact angles in the SP+A, SP+FP, and SP groups were similar for FZ. Both composites presented more uniform topography and smother surfaces following SP+A and SP+FP in comparison with SP. Therefore, additional polishing improved surface smoothness and decreased wettability of the composite resins studied. SP+FP produced smoother and less wettable surfaces for FZ and IP.