Influência da espessura e translucidez da cerâmica de dissilicato de lítio na alteração da cor final da restauração

Abstract

The aim of this study was evaluate the influence of thickness and translucency of lithium disilicate ceramic on the capability of masking a discolored tooths. A total of 120 specimens were prepared containing A1-color ceramic laminates of IPS e.max Press LT (Ivoclar Vivadent AG), IPS e.max Press, HT (Ivoclar Vivadent AG), and IPS e.max Press Impulse Value 1 (Ivoclar Vivadent AG) with four different thicknesses (0.3 mm, 0.5 mm, 0.7 mm, and 1 mm), cemented with Variolink Veneer resin cement of neutral color. CIELAB coordinates and color differences were calculated using a spectrophotometer. ΔE (color difference) was assessed by comparing a control specimen (IPS e.max Press, LT A1, [Ivoclar Vivadent AG]) with a thickness of 2 mm, called baseline, in the study groups. Data were subjected to the two-way analysis of variance. Subsequently, the Tukey test was used for multiple comparisons. Considering the threshold of a clinically perceived color change (ΔE = 3.3), the ceramics would have ΔE values below the threshold of 3.3 with the thickness of 1.0 mm, regardless of the ceramic used. Masking was possible only with low translucency and Impulse ceramics using 0.7- and 0.5-mm chips. None of the ceramics assessed showed ΔE values below the threshold of clinically perceptible color change at 0.3 mm (p = .006). Ultra-thin ceramics are not feasible as a therapeutic option for clinical cases that require color change. More opaque or opalescent ceramics showed better capability of dark substrate masking.