Influence of Illuminants on Optical Properties of CAD-CAM Materials

Objectives: The study aimed to assess the influence of illuminants on color and optical properties of CAD/CAM materials.
Methods: Disk-shaped (7.5 x 1.0mm; n=10/material) samples of HT-A2 CAD/CAM blocks of Lava Ultimate ([LU], 3M ESPE), Grandio Blocs ([GB], VOCO), VITA Enamic ([VE], VITA Zahnfabrik), and VITABLOCS Mark II ([VB], VITA Zahnfabrik) were fabricated using a precision cutting machine (ISOMET1000, Buehler). Samples were polished with SiC #600, #1200, #1500, and #2000-grit size abrasive papers. The color coordinates data of each sample placed over standardized white and black backgrounds were assessed with a spectrophotometer (CM-2600d/2500d, Konica Minolta) under CIE Standard illuminants D65 (daylight; 6,504K), A (incandescent; 2,856K), and F2 (fluorescent; 4,230K). The average data were used for the analysis of CIE color coordinates L*, a*, and b*, translucency (TP), contrast ratio Y (CRY), and whiteness index in dentistry (WID). One-way ANOVAs followed by Tukey HSD post hoc tests (α=.05) were used to analyze the data by comparing the effect of the illuminants on the evaluated properties of each material.
Results: In general, the results revealed significant differences for coordinates of chromaticity a* (LU, GB, VE, VB; P<.001), b* (LU P≤.001, GB P≤.035, VE and VB P<.001), and C* (LU and VE P<.001, GB P≤.007 and VB P≤.041) and for TP (LU, VE, and VB P<.001 and GB P≤.014), CRY (LU P≤.003, ENA P≤.041 and VB P≤.039), and WID (LU, GB, VE, VB; P<.001) under the illuminants tested. No differences (P≥.05) were observed between the L* values. The results of the color coordinates and optical properties of the evaluated CAD/CAM materials under different illuminants suggest a metamerism effect.
Conclusions: The illuminants D65, A, and F2 influenced the color and optical properties of the CAD/CAM materials.