Effect of Substrate Shades on the Color of Ceramic Laminates

Objectives: Ceramic laminate veneers are generally fabricated with varying thicknesses ranging from 0.3-1.0 mm, depending on the esthetic need to mask discolored teeth or slightly correct the contour of malpositioned teeth. The purpose of this in vitro investigation was to measure the color change resulting from applying 2 shades (T1 and O2) of IPS Empress all-ceramic material to 2 shades (A3 and C3) of XRV Herculite composite resin core material. Methods: A total of 40 disks were fabricated. 20 disks (15 x 0.5 mm) were cut of pressed ceramic, 10 disks for each ceramic shade. Additionally, 20 disks (15 x 4.0 mm) were fabricated from the light polymerized composite material, 10 disks for each shade. The ceramic disks were applied to the composite disks by means of the resin cement NX3 clear try-in gel. The specimen combinations were divided into 4 groups (n=5). Color measurement was done with a colorimeter (Minolta Chroma Meter CR-200b) configured with diffuse illumination/0-degree viewing geometry. CIE lightness (L*), chroma (C_ab*) and hue angle (h_ab*) values were obtained. Results:  Mean L*, C_ab*, and h_ab* are listed below:

Groups (n=5)          L*                 C_ab*                   h_ab*

T1-A3              64.6 ± 0.7        7.3 ± 0.6          92.8 ± 1.4

T1-C3              62.0 ± 0.3        6.6 ± 0.1          96.6 ± 1.1

O2-A3             69.6 ± 1.1        6.0 ± 0.6          96.4 ± 1.7

O2-C3             67.5 ± 0.9        5.3 ± 0.5          97.7 ± 0.9

Two-way ANOVAs showed significant differences in L* (P<.001) and C_ab* (P<.001) for a change in the composite substrate regardless of the ceramic material shade. Conclusion:  The selected color of 0.5 mm ceramic laminate veneer is affected by the change in color of the supporting substrate. This study is supported in part by Kerr Corp. Orange, CA, USA.