Inorganic filler content of resin-based luting agents and the color of ceramic veneers

ABSTRACT

Abstract The influence of inorganic filler content of resin-based luting agents (RBLAs) on color change (ΔE00), CIEL*a*b* (individual color coordinates), and translucency parameters (TP) of simulated ceramic laminate veneer (CLV) was investigated. RBLAs with low, intermediate, and high inorganic filler content (55%, 65%, and 75% mass fractions, respectively) were prepared. Feldspar ceramic (Vitablocs Mark II) specimens (1.2 mm × 0.8 mm, A1C shade) were bonded to simulated composite resin substrates (1.6 mm × 1.2 mm, A2D shade) using three experimental and a commercial (RelyX Veneer) RBLA (translucent shade). The ΔE00 was calculated by CIEDE2000 color difference metric under three conditions (before, immediately after, and 24 h after luting). The TP was calculated using CIEL*a*b* color coordinates measured over white and black backgrounds. Surface morphology of the RBLAs was analyzed. One-way and two-way analyses of variance with a post-hoc Tukey's test were used respectively to calculate TP, CIEL*a*b* coordinates, and ΔE00 (α= 0.05). Overall, the tested RBLAs presented clinically visible ∆E00 values under the three conditions evaluated. For all RBLAs, higher ∆E00 values were observed between measurements obtained before and immediately after luting. Different inorganic filler content did not significantly increase the opacity of the ceramic-luting agents-resin composite set. The variation in inorganic filler content did not influence significantly the TP of simulated CLV; although all of the experimental RBLAs tested yielded ∆E00 above the perceptibility threshold. The L*, a*, and b* individual color coordinates were cementation-dependent.