Comparison of translucency between indirect and direct resin composites

Abstract

Objectives: To measure the translucency of indirect and direct resin composites after curing, and to determine the influence of material and shade group combination on these properties. Methods: BelleGlass NG (BG, indirect resin composite) and Estelite Sigma (ES, direct resin composite), each composed in three shade groups (EN, OD and TL for BG; BS, AS and OP for ES) of 16 shades were investigated. Resin composite was packed into a mold (BEC) and was cured with a light-curing unit (CWL). Secondary curing was performed in a proprietary curing chamber (CIC) for BG material. Color was measured at the BEC, CWL and CIC conditions in the CIELAB scale using a spectrophotometer. Translucency parameter (TP) was calculated as the color difference between a specimen over a white and a black background. Results: TP values before curing were in the range of 7.7 (BG-OD) to 16.9 (ES-AS), and those after curing were in the range of 10.0 (BG-OD) to 21.5 (BG-EN). TP values of both materials were influenced by curing ( p < 0.05). There were significant difference in the TP values by the material and shade group combination, and the following homogenous subsets were found based on Tukey multiple comparison test: BG-OD < ES-OP < BG-TL = ES-AS = ESBS < BG-EN ( p < 0.05). Conclusions: BG material showed a wider range of TP values than ES, which would improve shade-matching capability of this material. Translucency should be considered when neighboring teeth are treated with different types of resin composites.