Effect of surface polishing and oral beverages on the surface profile and color stability of two composite resins – in vitro

Background: Surface quality of dental restorations is an important factor in determining the success of particularly anterior restorations. Surface roughness is one of the major causes of external discoloration, excessive plaque accumulation, gingival irritation, secondary caries and poor or less than optimal aesthetics of the restored teeth. These consequences are closely related to the type of composite material and the finishing and polishing systems used.
Material and Methods: The surface profiles of 72 samples each of a Nanofilled (Z-350) and a Micro-hybrid (Esthet-X) composite resins were determined pre and post finishing and polishing with two different finishing and polishing systems viz. Aluminium oxide discs (Soflex), Fine & extrafine grit aluminium oxide paste along with polishing discs and cones (Enhance) and Mylar strip was control. The samples from each group were further immersed in commonly consumed oral beverages viz. tea, coffee, cola and artificial saliva was the control for 30 days. The change in color for all the samples was determined using a Reflectance Spectrophotometer and CIELab system and post-immersion surface profile was determined using Profilometer and Scanning Electron Microscope.
Results: For both the composite resins Aluminium oxide finishing and polishing discs provided the smoothest surface as compared to fine grit aluminium oxide paste and Mylar strip. Coffee caused significant staining of composites followed by Tea; which was maximum after finishing and polishing with fine grit aluminium oxide paste. Cola was seen to cause a significantly rough composite surface as compared to other oral beverages. Micro-hybrid displayed more surface roughness and stainability as compared to Nanofilled composite resins.
Conclusion: The staining susceptibility of the composite resins may be attributed to their filler size and surface profile post finishing and polishing procedure. Coffee and tea can significantly discolor microhybrid as well as nanofilled composite resins.