Do universal adhesive systems affect color coordinates and color change of single-shade resin composites compared with a multi-shade composite?

The objective of the study was the impact of universal adhesives on color coordinates and color change of single-shade resin composites compared with a multi-shade composite after thermocycling. Five resin composites (Filtek Z250, Omnichroma, Vittra APS Unique, Zenchroma, and Charisma Diamond One) were used. The composites were randomly divided into three subgroups: two universal adhesive groups (Single Bond and Gluma Bond) and one control group (n=10). Color measurements were performed initially and after 10,000 thermocycling. Color change (Delta E-00) values were calculated using the CIEDE2000 formula. The two-way variance analysis was used (p<0.05). The lowest and highest Delta E-00 were exhibited in the Filtek Z250 and Charisma Diamond One (p<0.001, p<0.001, respectively). The highest Delta E-00 was exhibited in the Gluma Bond (p<0.001). An adhesive system may adversely affect the color change of resin composite materials. L and a values of resin composites decreased, and the b values increased after thermocycling.