Color stability of bulk-fill and universal composite restorations with dissimilar dentin replacement materials.

OBJECTIVE: To determine color changes in bulk-fill composite and universal composite restorations with dissimilar dentin replacement materials in extracted teeth after staining in red wine. MATERIALS AND METHODS: Cylindrical, 4 mm deep, class I cavities were prepared in 140 human molars. Bottom 2 mm was restored with Biodentine (Septodont), everX posterior (GC) or experimental HAP inserts. Each dentin replacement material was covered with a 2-mm layer of a universal composite Filtek Z250 or Z550 (3M ESPE) or Gradia Posterior (GC). Groups combining top composite layer and the underlying dentin replacement were designated as "composite_dentin replacement." Filtek Bulk Fill (3M ESPE) and Tetric EvoCeram Bulk Fill (Ivoclar Vivadent) were placed as a single 4-mm layer. Color measurements were performed using Vita Easyshade 4.0 (Vita Zahnfabrik) initially and after 48-hours storage in red wine at 37 degrees C. RESULTS: Color differences (DeltaE(oo) ) ranged between 2.1 +/- 0.7 (Z250_HAP) and 7.8 +/- 1.1 (Z550_everX). EverX resulted in higher DeltaE(oo) of the overlying composite than HAP (P < .001) and Biodentine (P = .006). Generally, DeltaE(oo) was affected more by decreasing lightness (DeltaL') than changes in chroma (DeltaC'). CONCLUSIONS: EverX resulted in higher DeltaE(oo) of the restoration than Biodentine and experimental HAP after staining in red wine. No significant differences in DeltaE(oo) may be expected in different composites with the same underlying dentin replacement material. The same was generally true for bulk-fill and universal composites. CLINICAL SIGNIFICANCE: Similar extent of color changes may be expected in bulk-fill and universal composites. Highly translucent everX might exhibit greater color differences irrespective of the capping composite than non-translucent materials. Clinicians have a wider choice of composite materials to cover a particular dentin replacement material, for example, everX or Biodentine, as similar color differences may be expected in various overlying composite brands.