Color Match of Resin Composite with Two-layer Technique

Abstract

This study investigated the effect of various layer thicknesses on color changes of light-cured composite resins. Two light-cured composite resins with different shades, Estelite Σ(ES, Tokuyama Dental, Shade; OA2, A2) , and Gradia Direct (GD, GC Corp., Shade; AO2, A2), were used. Resin disks (8 mm in diameter) with different thicknesses (0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0 and 4.0mm) were prepared. Colorimetric values of the specimens were measured immediately after curing against a three-colored plate using a fast spectro-photometer (CMS-35FS/C, Murakami Shikisai). The CIE L*a*b* color system was used for determining of the color. The data was subjected to Tukey's HSD test (p=0.05). The results were as follows: 1. The thickness of the resin composite which was not influenced by the white and black colored plates as background was 2.0mm for OA2 shade of ES and GD. These opaque shade resins exhibited acceptable masking effect against any background colors. 2. Two layers that could match the color of the A4 plate as well as reproduce the A2 color were obtained with the combination of 1.5 mm thickness of GDAO2 shade and 0.2 or 0.3mm thickness of GDA2.