Surface topography and bacterial adhesion of CAD/ CAM resin based materials after application of different surface finishing techniques

Abstract

Aim: This study evaluated the surface topography and bacterial adhesion of a hybrid ceramic and a nano ceramic resin composite after different surface finishes. Methods: Hybrid ceramic (Vita Enamic, VITA - EN) and nano ceramic resin composite (Lava Ultimate, 3M/ESPE - LV) blocks of 12 x 14 x 18 mm were cut into 1 mm slices. Each slice was divided into four specimens (6 x 7 mm) that were randomly allocated into 4 groups (n=8) according to the surface finishing: CTL - without surface finish (control); DB - wear with a diamond bur; VT - polishing system for hybrid ceramic (VITA); and DD - polishing system for ceramics (Dedeco). The specimens were analyzed regarding surface roughness parameters (Ra, Rz, Rq), sterilized and subjected to bacterial adhesion. Representative specimens from each group were observed by SEM and Confocal Laser Scanning Microscopy. Data were submitted to two-way ANOVA and Tukey's test (a=0.05). Results: EN had lower surface roughness and bacterial adhesion than LV (p < 0.05), regardless of the surface finish. The highest values for all roughness parameters was observed in LVDB group, differing from the other groups, which were not significantly different. Smaller bacterial adhesion values (CFU/mL) were observed for ENDD and ENVT, which differed significantly from the other groups, except ENCTL. For LV groups there was no significant difference between the different surface finishes (p > 0.05). The type of material and surface finish system significantly interfered with surface roughness parameters and bacterial adhesion. The hybrid ceramic performed better after polishing than the nano-ceramic resin. Conclusion: An adequate finishing/polishing technique should always be performed after any kind of adjustment to indirect restorations made with these materials tested.