The role of interface distance and underlying substrate on the color adjustment potential of single-shade composites

This study assessed how the distance from the composite interface and the underlying chromatic substrate affect the color adjustment potential (CAP) of two single-shade composites.

Cylinder-shaped specimens were created using Vittra APS Unique (VU), Charisma Diamond One (DO), and a shaded (A3) composite. Some single-shade specimens were surrounded by the A3 composite, forming dual specimens. Color measurements of simple specimens were taken against a gray background using a spectrophotometer. All specimens were positioned at a 45° angle in a viewing booth under illuminant D65, and images were captured with a DSLR camera against gray or A3 backgrounds. Image colors were measured using image processing software and converted to CIELAB coordinates. Color differences (ΔE₀₀ ) between the single-shade composites and the A3 composite were calculated. CAP was determined by comparing data from simple and dual specimens.

No clinically significant differences were observed between color measurements obtained from images and the spectrophotometer. CAP was higher for DO compared to VU and increased as the distance from the composite interface decreased and when specimens were positioned against an A3 background.

The color adjustment potential increased with decreased distance from the composite interface and against a chromatic background.

Achieving satisfactory color match in restorations using single-shade composites is crucial, and selecting an appropriate underlying substrate is essential. The color adjustment gradually decreases from the restoration margins towards its center.