Relative translucency of ceramic systems for porcelain veneers.

摘要

Objective. To compare the translucency of six different porcelains indicated for veneers, with various shades and opacities.;Methods. 13mm diameter and 0.7mm thickness discs were fabricated for the following porcelains (A1 shade; n=5): Empress Esthetic (EE), e.maxPress (EP), InLine (IL) (Ivoclar Vivadent); VITA PM9 (VPM), Vitablocks MarkII (VMII) (Vita Zahnfabrik); Kavo Everest G-Blank (KEG) (KaVo Dental GmbH) and Lava Zirconia (LZ) (3M ESPE). IL and LZ respectively served as positive and negative controls. Groups with different shades (BL2, BL4, A1, B1), as well as high (HT) and low translucencies (LT), were fabricated for e.maxPress. The luminous reflectance (Y) and color coordinates (CIE L*a*b*) were measured with a colorimeter (CIE illuminant D65, 2-degree observer function) with the specimens placed on black and white backgrounds. Contrast ratios (CR = YB/YW) and translucency parameters (TP= [(LB* - LW*)2 + (aB* - aW*)2 + (bB* - bW*)2]1/2) were calculated. One-way ANOVA and post-hoc Tukey's HSD tests were used to analyze the data (&agr; = 0.05).;Results. Statistically significant differences in CR and TP were found among porcelains (P .0001). The CR means in order of decreasing translucency were: VPM (0.15) > VMII (0.24), IL (0.25), KEG (0.26) > EP HTB1 (0.32), EE (0.34) > EP HTA1 (0.37), EP HTBL4 (0.37) > EP HTBL2 (0.43), EP LTA1 (0.47) > LZ (0.73). The TP means in order of decreasing translucency were: VPM (40.34) > VMII (33.66), KEG (33.52), IL (32.44) > EP HTB1 (27.96), EE (27.64) > EP HTA1 (26.59), EP HTBL4 (26.14) > EP HTBL2 (22.70), EP LTA1 (21.35) > LZ (10.43). Translucency of conventional feldspathic porcelain was comparable to that of machinable feldspathic porcelain. Pressable feldspathic porcelain presented the greatest translucency. Shade and thickness influenced lithium disilicate porcelain translucency.;Conclusion. Various ceramics systems designed for porcelain veneers present various degrees of translucency.