Influence of resin-coating agents on the roughness and color of composite resins

Statement of problem Resin-coating agents can be used to fill microstructural defects within composite resin restorations, which might result in a smoother surface. Nevertheless, data about the color stability and surface roughness of coated restorations are lacking. Purpose The purpose of this in vitro study was to compare the surface roughness and color stability of restorations before and after application of different resin-coating agents. Material and methods Forty specimens of composite resin (Filtek Z250) (diameter×height, 6×2 mm) were divided into 5 groups according to the surface treatments (n=8 per group): control (CTR), Fortify (FT), Lasting touch (LT), BisCover (BIS), and Fill Glaze (FG). The specimens were evaluated for surface roughness by using a profilometer with 3 readings for each specimen (separated by 300 μm) before immersion in a staining solution (coffee) and after 5 days immersed in coffee and for color stability (▵E) by using a spectrophotometer before being immersed in coffee (initial reading) and after 6 hours, 12 hours, 1, 2, 3, 4, and 5 days. Results Two-way ANOVA with repeated measures and the Tukey test showed that the CTR group showed the highest roughness values, similar to those of the FT and LT groups. The BIS and FG groups showed lower roughness than the other groups but similar results when compared with each other. All groups, except LT, showed increased roughness values after immersion in coffee solution, and the BIS group showed the lowest variation over time. Color alterations were found for all groups, with the CTR group showing the lowest ▵E values when compared with the other groups except for the BIS group. No correlation was found between surface roughness and degree of color change (P=.401). Conclusions The BisCover surface sealant showed the lowest surface roughness and the best color stability. Surface sealants can be used to fill microcracks and microgaps but should not be used as a substitute for polishing.