Effects of 5 manipulative variables on the color of ceramics used for computer-generated restorations

Monochromatic ceramic blocks used for computer-generated posterior restorations require color modification to achieve acceptable shade matches. However, it is not known whether manipulative variables affect the final color of these restorations. This study aimed to determine the effects of ceramic type, thickness, extrinsic colorants, glazing, and luting agent on the final color of monochromatic computer-generated ceramics.

One hundred forty-five ceramic specimens (12 mm x 10 mm) with different thicknesses were machined from monochromatic ProCAD ceramics (shades 100, 200, and 300; Ivoclar Vivadent) and Vita ceramics (shades A3.5 and 3M2; Vita). The influence of thickness on color was determined on ProCAD and Vita specimens with thicknesses of 1.0, 1.2, 1.5, 2.0, and 10.0 mm, and the influence of extrinsic colorants, glazing, and luting agent was determined on ProCAD and Vita ceramics of 1.5-mm thickness. Panavia F TC (Kuraray) was used to create a luting-agent backing of 100-microm thickness. CIELAB color coordinates (L*a*b*) were measured using a spectrophotometer, and color differences (DeltaE) between the specimens were calculated. The criterion for color difference was considered to be 1.5 DeltaE units. The data were statistically evaluated with ANOVA and the 2-tailed t test with a level of significance of 5%.

All 5 variables demonstrated significant differences for both ProCAD and Vita ceramics (P = .000). The DeltaE values were larger than 1.5 units.

Thickness and type of ceramic as well as extrinsic colorants, glazing, and a luting agent affect the color coordinates of monochromatic industrial ceramic.