A Nano-hybrid investigated: The correlation between surface characteristics and color after instrumentation

ABSTRACT

There is no evidence in the literature on the correlation between surface roughness of dental nanocomposites following application of instruments for finishing compared to instruments for both finishing and polishing and how this relates to the final color of the restoration. This study evaluated the correlation between roughness parameters (Ra and Rmax), of a nano-hybrid composite following finishing alone or finishing and polishing, and color. 70 specimens (8mmX8mmX2mm) of the nano-hybrid Heritage 7 were fabricated. One group of 10 specimens served as control. The remaining specimens of 10 per group were either finished sequentially with (a) diamonds (b) stones (c) carbides or finished and polished with (d) diamonds and Sof-lex discs (e) stones and Sof-lex discs, (f) carbides and Sof-lex discs. Following instrumentation the specimens were assessed using profilometry for surface roughness. Immediately following surface roughness measurements color was assessed using a spectrophotometer. Roughness and color data were assessed using a one-way analysis of variance (ANOVA) and post-hoc Bonferroni. Correlations between the color coordinates (L*a*b*) and ΔE and roughness parameters (Rmax and Ra) were analyzed at a 0.05 level of significance. There were no statistical changes in Ra measurements between finishing and finishing and polishing, however specimens finished with stones showed a dramatic change in Rmax values compared tocontrol and all the other finishing and finishing and polishing regimens. There was a correlation between Ra and color parameters L* and a* and ΔE. Green and white stones produced the most surface detriment in terms of surface roughness and color.