Comparison of Color Adjustment Potential of Composite Resin by Shade and Type

Abstract

1. Objectives

The aim of this study was to investigate and compare the blending effect of resin composite restorations according to shade and type. Blending effect occurs where the external color spreads into the resin composite, causing two different colors to form a mixed zone making it hard for the human eye to distinguish the two colors.

2. Methods

Six different products were selected according to different filler type, filler load, particle size, and resin matrix. From each product, 4 shades (A2, A3, A3.5, OA3) were chosen as the model shades. The resin composite specimen was cured with a red tile tightly attached on one end and a white tile on the other end. The XYZ coordinates from the Spectroradiometer were converted to CIELab values, and the CIEa* values were analyzed. CIEa* values followed the pattern of exponential decay and the values were fit into the general equation f(x)= a×e^((-b×x))+c. Blending effect was calculated as the distance where the CIEa* value measured 1 above the converging CIEa* value of the composite resin.

3. Results

Blending effect ranged from 1.535 mm (Premisa Dentin OA3) to 3.403 mm (Estelite Sigma Quick A2). Among the composite resin tested, Estelite Sigma Quick showed the highest blending effect overall. Of the 4 shades (A2, A3, A3.5, OA3), shade A2 of each composite resin showed higher blending effect within the same composite resin type.