Optical properties stability of light-cured versus pre-cured CAD-CAM composites

Abstract

The aim of this study was to evaluate the optical properties changes after staining of pre-cured (PC) and light-cured (LC) composites. Specimens were prepared using different LC composites (GrandioSO - Voco, Filtek Z350 - 3M/ESPE, Opallis - FGM and Kalore - GC) and four PC composites (Grandio Blocs - Voco, Lava Ultimate - 3M ESPE, Brava Block - FGM and Cerasmart - GC) (n=20). Baseline color, gloss, translucency, and fluorescence were evaluated. Staining protocol was performed for 15 days and the final optical properties were reevaluated. The changes on each property were calculate ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta$</tex> Gloss, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta$</tex> Trauslucency, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta$</tex> Fluorescency, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta\mathbf{E}^{*}00)$</tex> . Data were analyzed by ANOVA and Tukey's test <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\alpha=5\%)$</tex> . Changes on all properties were observed after staining for all materials, with darkening and reduction of gloss, fluorescence and translucency. Non-significant differences were observed between the light-cured and pre-cured materials of the same manufacturer for the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta\mathrm{G}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta\mathbf{T}$</tex> , but significant differences existed for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \mathbf{F}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta\mathbf{E}^{*}00)$</tex> . For <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \mathbf{F}$</tex> , the only significant differences were observed between Brava Block and Opallis (smaller). For <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \mathbf{E}^{*}{}_{00}$</tex> , only the light-cured composites GrandioSO and Z350 showed significant less change than the corresponding blocks. Pre-cured composites were affected the same way than light-cured ones by the staining in relation to the reduction of gloss and translucency. A higher reduction of fluorescence was observed only for one brand of block and was similar for the others. Two brands the light-cured materials showed less staining, while for the others was similar. The effects of staining vary according to the composite formulation.