Final color of luted CAD/CAM veneers fabricated from multilayered blanks

Method: Thin slices (N=60) with 2 different thicknesses (A:8×8x0,55 mm and B:8x8x0,8mm; n=30/group) were obtained from multilayered glass ceramic blocks (IPS Empress CAD C14 A2, IvoclarVivadent) using a diamond saw (Isomet 1000, Buehler). Resin die material specimens were prepared (IPS Natural Die Material, B1, IvoclarVivadent) (8×8×4mm) (n=60) and divided into 2 different resin cement colours (D:-3, L:+3) and 1 control group (C:translucent) and each slice was luted to the composite specimens using a dual-curing resin cement (Variolink II, IvoclarVivadent) under a constant load of 250g and light-polymerized for 120s (Bluephase G2, IvoclarVivadent). Specimens were placed on a white background and CIELab values for each layer of the blank slices [incisal (In), body (By) and cervical (Ce)] were recorded using a dental contact spectrophotometer (VITA Easyshade Advance, Vita Zahnfabrik). The values were calculated as ΔE and the data were statistically analyzed (One-way ANOVA, Shapiro-Wilk).

Result: Mean ΔE values for A and B were significant for In (A:6,2±1,1;B:6,6±1,2) By (A:5,1±2,6; B:3,9±1) and Ce (A:5,3±2,7;B:3,8±1,2), respectively .(p˂0,05). While mean ΔE values in In for D and L for A and B groups were significantly higher (6,3±1,2;6,6±1,2) than By and Ce for D (4,4±2,4;4,6±2,6 ) and L (4,6±1,4;4,5±1,7) groups (p< 0.05), respectively. Mean differences between By and Ce for A (5,1±2,6; 5,3±2,7) and for B (3,9±1;3,5±1,2)  groups were insignificant (P≥0.05) while for In the differences were significant (6,2±1,1 for A and 6,6±1,2 for B).  

Conclusion: The color changes for body and cervical regions of multilayered ceramic veneers were not affected from resin color or ceramic thickness while only incisal area was affected. Translucency of each layer in ceramic veneer fabricated with multilayered blanks should be considered  for clinical situations