Effects of thickness and background color on the translucency of CAD/CAM ceramic materials

Abstract

The aim of this study was to compare the translucency of different thicknesses of three different CAD/CAM ceramic materials (zirconia-reinforced lithium silicate (Suprinity), lithium disilicate (IPS e.max CAD), and hybrid ceramic (Enamic). A total of 180 specimens were prepared from each materials at different thicknesses (0.4 mm, 0.5 mm, 1 mm, 1.5 mm, and 2 mm). A spectrophotometer was used to measure the translucency using a contrast ratio (CR) against white and black backgrounds for all the specimens. Data was analyzed using ANOVA, one-sample t-test, and post-hoc multiple comparison test at a significance level of P ≤ 0.05. The CR increased significantly when the material thickness increased for all specimens of each material type (P ≤ 0.05), except for the e.max material, as there was no significant difference between 0.4 and 0.5 mm, and between 1.0 and 1.5 mm. The differences between the materials became more apparent with the increase in thickness. In addition, when comparing the three types of material, zirconia-reinforced lithium silicate appeared to have the highest contrast ratios. The study provides knowledge about the translucency of the different thickness of the CAD/CAM dental restorative materials which could help to overcome the disadvantages of the translucency in certain clinical situations.