Difference in opalescence of restorative materials by the illuminant

ObjectivesTo determine the differences in the opalescence parameter (OP) of indirect and direct resin composites, veneer ceramics and bovine enamel relative to the CIE standard illuminants D65, A and F2.MethodsBelleGlass NG (indirect resin; 10 shades) and Estelite Sigma (direct resin; 12 shades), and 4 shades of veneer ceramics were investigated. Bovine enamel was used as a reference. Reflected and transmitted colors of specimens were measured relative to the illuminants D65, A and F2 with a reflection spectrophotometer. OP values relative to the three illuminants [OP(D65), OP(A) and OP(F2)], difference in OP (ΔOP) and OP difference ratio relative to OP(D65) [ΔOP/OP(D65)] by the change of illuminants were calculated. Within each restorative material, ΔOP and ΔOP/OP(D65) values were analyzed with two-way analysis of variance (ANOVA), with the fixed factors of the shade designation and the combination of illuminants (α = 0.05).ResultsΔOP and ΔOP/OP(D65) values were influenced by the two factors within each restorative material based on two-way ANOVA. High opalescent materials showed higher ΔOP values. OP(D65) was lower than OP(F2) and OP(A) values. Restorative materials showed lower ΔOP/OP(D65) values than bovine enamel. Correlation coefficients between OP values relative to different illuminants were higher than 0.961 (P < 0.01).SignificanceDirect resin composites instead of ceramics or indirect resin composites should be recommended in clinical dentistry since they showed similar opalescence properties as compared with natural tooth enamel.