Surface analysis of six composites: Atomic Force Microscopy and Rugosimeter

Objectives: To compare and quantify the surface roughness of three different resin composites of enamel and dentin shades (XRV Herculite®, Herculite® XRV Ultra and Enamel Plus HRi®) with a roughness test and atomic force microscopy (AFM).
Methods: Using a silicone mould, 60 resin composite discs were prepared and analysed with a rugosimeter. 10 specimens were prepared and assigned to one of the 6 groups: 1) XRV Herculite® enamel shade, 2) XRV Herculite® dentin shade, 3) Herculite® XRV Ultra enamel shade, 4) Herculite® XRV Ultra dentin shade, 5) Enamel Plus HRi® enamel shade, and 6) Enamel Plus HRi® dentin shade.
12 additional resin composite discs were prepared using a plastic caster – 2 from each group – and analysed by atomic force microscopy (AFM). The specimens prepared for surface evaluation were finished and polished with the Jiffy Polisher® system, consisting of a sequence of three polishing rubber points; each rubber was used for 90 seconds under water refrigeration.
Results: According to the Ra criteria, there are no statistically significant differences between the different groups. However, the composites Herculite XRV Ultra ™ featured the minor Ra (0,304 ± 0,023) and the composites Herculite XRV ™ presented the roughest surface (0,388 ± 0,028). The data were analysed according to One-Way ANOVA with a confidance level of 95%.
Conclusions: Although no difference in surface roughness was observed among the resin composites, all of them presented roughness values higher than those mentioned in the literature as ideal.