Color adjustment potential of universal shade bulk-fill resin composites

This study investigates how the cavity depth of restorations influences the color adjustment potential of universal shade bulk-fill resin composites. Standard cavities, with diameters of 4 mm and depths of either 2 or 4 mm, were created at the center of artificial teeth occlusal surfaces. A structural-colored bulk-fill resin composite and two pigment-incorporated universal shade bulk-fill resin composites were used. Each resin composite was placed into the cavity to assess its color adjustment potential in relation to the artificial tooth color. Following application, the resin composites’ surfaces were polished using diamond-impregnated silicone polishers. Color difference analysis revealed ΔE*ab values of 3.3–4.6 and 2.2–9.6 for structural-colored resin composites and pigment-incorporated universal shade resin composites, respectively, as well as ΔE₀₀ values of 2.7–3.4 and 1.7–5.8 for these resin composites, respectively. These findings suggest that the tested bulk-fill resin composites’ color adjustment potential was influenced by restoration depth.