Evaluation of resin composite translucency by two different methods.

The purpose of this study was 1) to compare the translucency of seven different types of composite materials and three different shade categories (dentin, enamel, and translucent) by determining the translucency parameter (TP) and light transmittance (%T) and 2) to evaluate the correlation between the results of the two evaluation methods. Three shades (dentin A3, enamel A3, and clear translucent) of seven composite materials (Beautifil II [BF], Denfil [DF], Empress Direct [ED], Estelite Sigma Quick [ES], Gradia Direct [GD], Premise [PR], and Tetric N-Ceram [TC]) from different manufacturers were screened in this study. Ten disk-shaped specimens (10 mm in diameter and 1 mm in thickness) were prepared for each material. For the TP measurements, the colors of each specimen were recorded according to the CIELAB color scale against white and black backgrounds with a colorimeter and used to calculate the TP value. For the %T measurements, the mean direct transmittance through the specimen in the range between 380 and 780 nm was recorded using a spectrometer and computer software. Two-way analysis of variance (ANOVA) tests were performed to compare the TP and %T for the composite materials and shade categories. One-way ANOVA and Tukey tests were used for the seven composite materials per shade category and the three shade categories per composite material. The correlation between the two evaluation methods was determined using the Pearson correlation coefficient. All statistical procedures were performed within a 95% confidence level. TP differed significantly by composite material within each shade category (p<0.05) and by shade category within each composite material (p<0.05). %T differed significantly by composite material within each shade category (p<0.05) and by shade categories within each composite material (p<0.05), except for BF and ES. For the two evaluation methods, TP and %T, were positively correlated (r=0.626, p<0.05). These methods showed strong correlation for each composite material except ES (r=0.763-0.992, p<0.05) and moderate correlation for each shade category (r=0.403-0.528, p<0.05).