ObjectiveThis study aimed to evaluate the influence of ceramic type and thickness on the masking ability and final aesthetic effects of chairside machinable all-ceramic crowns.MethodsSix kinds from three types chairside machinable ceramic materials (IPS e.max CAD HT/MT/LT, IPS Empress LT, and VITA Suprinity HT/T) in shade A2 were fabricated to slice specimens into 1.0, 1.5, and 2.0 mm-thick sections (n=10). The color parameters of the specimens against black and white tiles and four resin substrates (A2, A4, B3, and C4 shade) were measured with a spectrophotometer. The translucency parameter (TP) was calculated using color parameters measured over standard white and black backgrounds. The color differences (ΔE) were calculated between there substrate shades (A4, B3, C4 ) and A2 shade (control group). Two-way analysis of variance (ANOVA) was performed on the TP values. The two va-riables were ceramic type and ceramic thickness. Three-way ANOVA was used to determine the effects of ceramic materials, ceramic thickness, and substrate shades on the ΔE values, followed by Tukey test for multiple comparisons (α=0.05).ResultsCeramic type, ceramic thickness, and substrate shade significantly affected the ΔE values (P<0 .001). the l* and b* values of the specimens increased with increasing ceramic thickness, except in substrate a2, whereas the δe values decreased. the color difference of all 1.0 mm-thick specimens or all specimens over the substrates c4 shade exceeded the clinically acceptable threshold (δe>3.3).ConclusionThe masking ability of chairside machinable all-ceramic crowns is influenced by ceramic type and thickness, and ceramic material. The thickness of ceramic less than 2.0 mm cannot mask the gray shade abutment.
