Abstract
Statement of problem. Information regarding the masking ability of computer-aided design and computer-aided manufacture (CAD-CAM) resin-matrix ceramic materials with different compositions is scarce. Purpose. The purpose of this in vitro study was to evaluate the effects of background color and thickness on the optical properties (color and translucency) of CAD-CAM resin-matrix ceramics.Material and methods. Twelve rectangular specimens were fabricated at a different thickness (1, 1.5, and 2 mm) (n=12) from each of the resin-matrix ceramic materials: Shofu block (SB), Lava Ultimate (LU), CERASMART (CS), VITA ENAMIC (VE), Crystal Ultra (CU), and the VITABLOCS Mark II feldspathic ceramic (VB). The color of the specimens over amalgam, titanium, enamel, and dentin backgrounds was measured with a spectrophotometer, and the color differences (delta E*(ab)) were calculated by using the Commission Internationale de l'Eclairage (CIE) 76 formula. The difference in color of the specimen over the black and white backgrounds was used to calculate the translucency parameter (TP). ANOVA was used to statistically test whether material, background, and thicknesses influenced delta E*(ab) and TP values. Post hoc comparisons were performed to determine the significant difference among the groups (a=.05).Results. The interaction with 2 between factors demonstrated that the material was a factor that significantly influenced delta E*(ab) (P <.001). The highest mean +/- standard deviation of delta E*(ab) was recorded in the combination of VB material and 2-mm thickness (1.84 +/- 0.37), and the lowest with CS material with 1.5-mm thickness (0.47 +/- 0.24). The type of material and specimen thickness significantly influenced TP (P <.001). The highest and lowest mean +/- standard deviation of TP were recorded for the 1-mm-thick CS (14.20 +/- 0.90) and 2-mm-thick SB (4.91 +/- 0.42) specimens, respectively.Conclusions. CERASMART resin-matrix ceramic and VITABLOCS Mark II feldspathic ceramic exhibited high and low masking abilities over the investigated background substrates, respectively. However, irrespective of the thickness, all study materials exhibited acceptable masking abilities.