Impact of in-office bleaching agents on the optical properties of universal resin composites: an in vitro analysis.

Background: The aim of this study was to evaluate the surface color stability, transluceny and gloss changes of seven different universal resin composites after bleaching treatment protocol.

Methods: Fifty-six disc-shaped specimens were prepared, with eight specimens each of the universal resin composites Filtek Z250 (F), Filtek Universal (FU), Harmonize (H), Vittra Unique (VU), Omnichroma (O), Essentia Universal (EU), Charisma Diamond One (CDO). Prepared specimens were divided into two for color change, translucency, gloss (n = 8). Initial color and gloss measurements and translucency calculations were made on the prepared samples. After measurements, in-office bleaching gel was applied to the specimen surfaces three times, and each application time was 15 min. After the bleaching protocol, the measurements were repeated, and the values were statistically analyzed using the one-way ANOVA, Tukey HSD test, Kruskal-Wallis test, Dunn's test, Paired samples t-test (p < 0.05).

Results: Vittra Unique group had statistically significantly higher ΔE values than the FU, H and EU groups (p < 0.05). CDO had significantly higher ΔE than the H group (p < 0.05). O had higher TP values than all other groups for T0 and T1 (p < 0.05). A significant decrease in gloss values ​​was observed after bleaching in all material groups compared to the initial.

Conclusions: The organic content of resin composites is an important factor in color stability, with higher molecular weight resins may being less affected by bleaching agents.