Comparing the Translucency of several enamel and universal- shade composite resins

 Translucency is one of the important optical properties of tooth color materials and it is greatly affected by the thickness of material. This study concerns comparing the translucency parameter (TP) of five different composite resins in different thicknesses.

Five brands of composite resins; Gradia (GC) ,Crystalline (Confi-dental) Vit-l-escence (Ultradent) in A2, and Herculite XRV (Kerr), Opallis (FGM) in enamel A2 (EA2) shades were selected to enroll the study. Color coordinates of each composite were determined at 0.5, 1, and 1.5 mm thicknesses on a white backing, the backing of material itself and a black backing were calculated by using a spectrophotometer to evaluate the translucency parameter (TP) of the study materials. The masking ability was also calculated from the specimens on the material itself and on black backing. The values under 2 were estimated as imperceptible. One-way ANOVA, T-test and Tukey HSD were employed for statistical analysis.

Opallis (EA2) showed the less TP values in all thicknesses in comparison to the other materials (p< 0.05) but there was no statistically significant difference between TP values of Gradia and Opallis in 1.5 and 0.5 mm-thick. The masking ability values recorded for all specimens at different thicknesses, were in the range of perceptible.

In this study, translucency of Opallis (EA2) and Gradia(A2) was less than the other enamel /universal shade composites. For this reason, it would be concluded that if the restoration thickness is ≤1.5mm, these enamel/universal shade composite resins cannot mask the black background color.