Staining Susceptibility of Recently Developed Resin Composite Materials

Objectives: To evaluate the colour stability of 3 recently developed resin based materials continuously exposed to various staining agents.
Methods: Eighty disc-shaped specimens were made of each of the 3 tested composites (Essentia, Brillant, Inspiro). Half of them were of 1mm thickness, the other half 1.2mm thickness. The thuicker group was than polished up to 4000 grit and reduced to 1mm thickness, too.
All specimens after 24 h dry storage in an incubator (INP-500, Memmert), received an initial colour measurement by means of a calibrated reflectance spectrophotometer (SpectroShade, MHT). Specimens were then divided in 6 groups (n=6) and immersed in 5 staining solutions or distilled water (control). All specimens were kept in an incubator at 37°C for 28 days. Staining solutions (red wine, curry mixed water, curry mixed oil, tea and coffee) were changed every 7^th day to avoid bacteria or yeast contamination. After 28 days of storage spectrophotometric measurements were repeated and L*a*b* scores once more recorded to determine the colour (ΔE00) changes.
Results: All tested materials showed significant colour changes after 28 days staining immersion.
When considered over a black background ΔE of polished samples varied from 1.7 (Brillant/distilled water) to 24.1 (Brillant/wine). When considered over a white background ΔE varied from 1.1 (Essentia/distilled water) to 32.5 (Inspiro/wine).
When considered over a black background ΔE of unpolished samples varied from 1.1 (Essentia and Inspiro/distilled water) to 25.8 (Essentia/wine). When considered over a white background ΔE varied from 1.4(Inspiro/distilled water) to 33.1 (Inspiro/wine).
Conclusions: Staining of restorative materials seems to be dependent on the composition of the product itself.