Mascaramento de substratos escurecidos utilizando sistemas restauradores indiretos

Abstract

This study evaluated the masking ability of discolored substrates using Indirect Restorative Systems (IRS). Specimens (1.5 mm) were prepared from five different IRS: CAD-on (Zenostar + Crystall / Connect + IPS e.max CAD); YLD-T (IPS e.max ZirCAD + IPS e.max Ceram); LDC (IPS e.max CAD); YZW (Zenostar); PICN (Enamic). Specimens (n= 5) were coupled (A) with a try-in paste or cemented (C) with a dual-cured resin cement, both having matching colors, on three different shades of substrate (Natural Die Material). Samples of resin cement and try-in paste (1mm thick; n=5) were also made. Color coordinates were obtained using a spectroradiometer on a white background, using standard lighting conditions and optical geometry of 0/45°. Color differences (ΔE) of all specimens (A and C) on each colored substrate and between A and C specimens were calculated using the CIELAB and CIEDE2000 metrics. Translucency of IRS was evaluated using the translucency parameter (TP). Whiteness index for dentistry (WID), TP and ∆E between specimens of resin cement and try-in paste were evaluated. Values of ΔE were associated to the perceptibility (PT) and acceptability (AT) thresholds, and statistically analyzed using analysis of variance (ANOVA) and Tukey test (α= 0.05). There were significant differences on TP among the IRS, except between CAD-on and LDC (p> 0.05). YLD-T showed the lowest TP and ΔE values, being the only IRS below AT for both A and C specimens. All ΔE values between A and C specimens were below AT for both metrics (CIELAB and CIEDE2000), except for one situation. Differences in WID, TP and ΔE values were found between the resin cement samples and the try-in paste. YLD-T showed the best masking ability to discolored substrates.