Color Stability of Resin-composites After Staining With a Black Tea

Objectives: The purposes of this study was to evaluate color stability of two nano hybrid resin-based composite restorative materials {Filtek Z250 XT (3M ESPE) and Herculite XRV Ultra (Kerr)} following immersion in black tea (Lipton).
Methods: Thirty shade B2 cylindrical specimens (10 mm diameter, 2 mm thickness) were prepared from each composite resin according to manufacturer's instructions using metal molds. Specimens were stored in distilled water for 48 hours at 37°C. The top surfaces of all specimens were wet-polished with 800-, 1000, 1500-, and 2000-grit silicon carbide papers, consecutively and then were randomly divided into two groups/15 each. All specimens were measured for color values according to the CIEL*a*b* color scale using a spectrophotometer (Testing Phase One – T1). Specimens in each group were immersed in black tea for one hour per day at 37°C for two weeks. The back tea was prepared daily prior immersion period. Following completion of the immersion time. All specimens were measured for color (Testing Phase Two – T2) similar to testing phase one T1.
Results: The mean (+SD) ΔE values of Filtek Z250 XT at baseline before immersion was 1.9±1.1 and for Herculite XRV Ultra was 1.1±0.7. There was no significant difference in ΔE values between the two types of composite resins (P=0.073). The mean (+SD) of ΔE* values of Filtek Z250 XT after immersion in black tea was 26.3±0.5 and for Herculite XRV Ultra was 25.1±0.9. A statistically significant change in color for both composite materials was evident when comparing between ΔE values testing phase T2/Stained and testing phase T1/baseline (control) (p<0.01). After being stained, no significant difference in ΔE values was found between both composite materials (P>0.05).
Conclusions: Both tested restorative materials were susceptible to discoloration by black tea after immersion for 14 hours. The color change values were not related to the type of resin-based composite used.