Color correspondence between Vita Shade guide and three different composite

Objectives: selection of the correct shade of a resin composite restorative material is a challenge in esthetic dentistry. Aim of this study was to evaluate the correspondence the shade indication of three structurally different resin composites with the Vita shade guide. Methods: the following materials were selected for the trial: Gradia (G) (GC, Tokio, Japan), Tetric Ceram (T) (Ivoclar, Schaan, Liechtenstein) and Supreme (S) (3M, St. Paul, MN, USA). For these products, 6 Vita shade were selected: A2, A3, A3.5, A4, B2, B3. For each product at each color, the samples were made with a proprietary mold that allowed to obtain samples of resin composite products with the same size and shape of the Vita shade guide samples. The samples were measured in the CIE L*a*b* system with a dental color measuring device (SpectroShade, MHT, Ch) and the differences in color were calculated using the formula DeltaE=((L1-L2)2+(a1-a2)2+(b1-b2)2) 1/2 (Clarke, 1983). Results: the results (table) have to be regarded with the consideration that DeltaE=3.3 is considered the limit for the eye in appreciating a difference in color. All the system tested showed an high degree of comparison mismatch when compared with Vita Shade Guide. Supreme showed the higher degree of comparison mismatch. A deeper analysis of the results showed that the high mismatch of Supreme was mainly due to DeltaL* value. This study showed that 83% of the color comparisons performed mismatch on an eye-appreciable level. Supreme showed L* values significantly lower than the corresponding Vita color. Conclusion: fabrication of custom shade guide is strictly recommended as all the materials tested showed a significant mismatch with the corresponding Vita shade.