The capacity of conservative preparations for lithium disilicate glass-ceramic laminates luted with different resin cements to mask different substrate shades: A minimally invasive esthetic approach.

Abstract

Demonstrate the ability of 0.5 mm thickness lithium disilicate laminates associated with resin cement to mask different substrate saturations. 60 specimens (n = 5) were prepared with CAD/CAM lithium disilicate glass-ceramic IPS e.max CAD, 0.5 mm thick, in three degrees of translucency (HT, MT and LT); cemented by Variolink Esthetic LC Light+ (L) and Neutral (N) on composite resin substrates A1 and A4 shades. Color measurements were performed by a spectrophotometer (CM-3700d -Konica Minolta). The L*, a*, b* parameters of the tri-layer structure (laminate/ resin cement/ substrate) were used to calculate color difference ( ) by CIEDE2000 formula and Translucency Parameter ( ). This study adopted = 0.8, as perceptibility threshold (PT), and = 1.8, as acceptability threshold (AT). Statistical analyses were performed by one-way ANOVA and Tukey tests (a = 0.05). Color difference between resin cement shades showed statistical differences (p < 0.0001) and > 1.8 for all groups. Color difference between substrates saturations showed a significant statistical difference (p < 0.0001) and values above AT for all groups. The demonstrated significant statistical differences (p < 0.0001). The LTL combination, the opaquest set, showed the smallest values between substrate shades differences, however, above AT. The translucency of the lithium disilicate, the substrate saturation and the resin cement opacity influenced final color of restoration. The ceramic translucency impact on final color was reduced by opaque resin cement. Furthermore, the LT lithium disilicate and the Light+ resin cement reduced the translucency of the restoration, contributing to mask saturated substrate. This study shows the influence of conservative lithium disilicate laminates with different degrees of translucency associated with resin cement on final color of saturated substrate restorations. A minimally invasive esthetic protocol for masking substrates is demonstrated by associating low translucency ceramic laminates and opaque resin cement.