Color Characteristics of One Shade Composites After Photoaging

Objectives: The aim of the study was to evaluate the color stability (CIE L*a*b*) and changes in translucency parameter (Tp) and opacity (Op) of one shade composites before and after photoaging.
Methods: The materials tested were Charisma Topaz (CT), Essential Universal (EU), Majesty ES (ME) and Omnichroma (OM), whereas an A2-shade composite (Gaenial Anterior/RF) was used as a control. Disk-shaped specimens (14mmX2mm, n=10/material) were prepared (4x20s exposure/surface, 1.5W/cm²) and measurements of ΔΕ, ΔΤp, ΔΟp, were recorded before and after photoaging (96h 300-800nm, 37^oC, 765 W/m² irradiance) employing a UV-Vis spectrophotometer with an integrated sphere. Statistical analysis was performed by 1-way ANOVA plus Tukey test per property.
Results: The rankings of the statistically significant differences were OM>RF>ME>3.3>CT>ES (ΔΕ), ΟΜ>ΜΕ>RF>CT>EU (ΔΤp) and ME>OM>EU>RF>CT (ΔΟp).
The most impostant color changes were registered in OM (ΔΕ:9, ΔL*:-6.2, Δb*:-6.6, ΔΤp: -7.6) and ME (ΔOp: -4.3).
Conclusions: Photoaging, which reveals the inherent material color instability due to the presence of chromophore or auxochrome groups, without any external staining capacity, demonstrated important levels of color, transparency and opacity changes mainly on one shade composites. These changes may create esthetic problems in simplified one shade restorations.