Effect of whitening mouthrinses on bulk-fill composites

To evaluate the effect of whitening mouthrinses on sorption (SP) and solubility (SL), percentage of microhardness change (%M), loss of surface (LS), and color change (ΔE) in bulk-fill composites when compared with conventional composites.

Three bulk-fill composites, Surefil SDR (SF), Filtek Bulk-Fill (BF), and Filtek Bulk-Fill Flow (BFF), and one conventional resin, Filtek Z350 (FZ), were selected. Eighteen samples of each composite were subdivided into three groups based on the type of treatment: Listerine Whitening mouthrinse (LW), Colgate Plax Whitening mouthrinse (CP), and distilled water (DW; control). The samples were prepared according to ISO 4049:2009. Color, roughness, and microhardness were evaluated before and after treatment, while SP and SL values were measured after treatment. The surface morphology of the specimen was examined using scanning electron microscopy. Data were analyzed using two-way ANOVA and Tukey's test.

FZ presented significantly lower ΔE when immersed in DW. Additionally, LS was lowest in FZ when compared with the other resins. SF and BFF demonstrated high %M. SL was significantly higher in SF, whereas SP was lowest in BFF after CP treatment. No significant alterations in surface morphology were noted in the BF composites. The BF composites showed a decrease in their properties after immersion in the two types of mouthrinses or in DW, without alterations in the surface morphology.

Flowable bulk-fill composites showed the greatest changes in their properties when exposed to different mouthrinses or water. Thus, they should be used with caution in areas that will stay exposed to the oral cavity.