Colorimetric study about the stratification’s effect on colour perception of resin composites

To evaluate the influence of a different order of dentin and enamel layers on stratification appearance of different resin composites. 144 Dentin (D) and Enamel (E) composite samples (Clearfil Majesty ES-2 Premium, Brilliant EverGlow, Estelite Asteria), 1 mm thick, were divided into 12 configurations for each composite, with Enamel–Dentin–Dentin–Enamel (EDDE) assumed as target. The colour specification was conducted using a spectrophotometer, elaborating the results with the CIE L*a*b* colour coordinates and calculating the colour difference in terms of \(\Delta E_{ab}^{*}\) quantity. A value of this last major of 3.3 was considered not clinically acceptable. Moreover, data were analyzed using two-way analysis of variance and Tukey post hoc test (P < 0.05). For Clearfil Majesty ES-2 Premium and Brilliant EverGlow, six configurations showed \(\Delta E_{ab}^{*}\) > 3.3 compared to gold standard EDDE. \(\Delta E_{ab}^{*}\) was influenced especially by b* and L* coordinates (P < 0.05). EDED showed no visual difference (0 < \(\Delta E_{ab}^{*}\) < 1.1) for both composites. For Estelite Asteria, two configurations reported \(\Delta E_{ab}^{*}\) > 3.3 compared to EDDE. In particular, the L* coordinate influenced \(\Delta E_{ab}^{*}\) results (P < 0.05). EDDD was the best configuration (0 < \(\Delta E_{ab}^{*}\) < 1.1). Within the limits of a vitro study, Brilliant EG showed more dependence from order and thickness of stratification (resulting more similar to Clearfil Majesty ES-2 Premium); therefore, it could be indicated for more complex aesthetic restorations. Estelite Asteria seems to be able to balance small differences in thickness of dentin and enamel layers, and consequently, it is more indicated to different clinical situations.