Influência do conteúdo de carga inorgânica nas propriedades ópticas e mecânicas de agentes de cimentação resinosos.

Abstract

The inorganic filler content of resin-based luting agent could influence the quality and durability of the adhesion between ceramic and luting agent, as well as, the optical properties of the ceramic restorations. Two in vitro studies are presented in this study. The article 1 evaluated the influence of inorganic filler content of resinbased luting agents (RBLAs) and the adhesive use on the bond strength (μTBS) and interface morphology of luted feldspar ceramic. RBLAs with low, intermediate and high inorganic filler content (55%, 65% and 75% of mass fraction, respectively) were prepared. The modulus of elasticity (E), Poisson's coefficient (v), viscosity and degree of conversion (DC) of these luting agents were also measured (n=3). The RelyX Veneer (3M ESPE) was used as commercial reference. Feldspar ceramic blocks (Vitablocks Mark II; Vita Zahnfabrik) were luted to composite resin, originating eight groups according to the different RBLAs and use of adhesive (n=30). Data of E, ν, DC and viscosity were analyzed using one-way analysis of variance followed by post-hoc Tukey’s test (α= 0.05) and confidence intervals for the means (95% CI) were calculated for μTBS, σ0, and m. The increase of their inorganic filler content was associated with increased E and viscosity of the experimental RBLAs, while v and DC were not influenced. The use of adhesive improved the μTBS and σ0 for the commercial and RBLAs with high filler content. The article 2 evaluated 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). The ΔE00 and PT were calculated based on the CIEL*a*b* color coordinates measured with a spectrophotometer. The ΔE00 was calculated by the color difference CIEDE2000 obtained for each ceramic specimen (1.2 mm x 0.8 mm, A1C) luted to the composite resin substrate (1.6 mm × 1.2 mm, A2D) using the luting agents In the (translucent shade) under three conditions (baseline, immediately and 24h after luting). The PT was calculated from the measurements of the specimens obtained over white and black backgrounds. Surface morphology of RBLAs and composition of commercial also were analyzed. One-way and two-way analyses of variance with a post-hoc Tukey test were used respectively to calculate TP and ΔE00. For CIEL*a*b* coordinates, each pair of variable was compared using the Student t-test (α= 0.05). Overall the RBLAs tested presented clinically visible ∆E00 values under the three conditions. For all RBLAs, higher ∆E00 values were observed between measurements obtained before and immediately after luting. The variation of inorganic filler content did not influence significantly the TP of simulated CLV. The L*, a*, and b* individual color coordinates were cementation dependent.