Color Shifting of Resin Composites

Objectives: To evaluate visual and instrumental color shifting of resin composites. Methods: Test shades were as follows: A1, A2 and A3 of Clearfil Majesty Esthetic (M); Filtek Supreme Plus (F); Artiste Nano Composite (A); and Estelite Sigma (E). Control shade was A3.5 of M. Disc-shaped specimens of all composites (D=10 mm, 2-mm thick, n=5) were made. “Dual” specimens: outer ring (outer D=10 mm, 4-mm thick, with inner ring holes of D=4 mm, 2-mm thick, n=5 per composite) were made of the control shade. Inner ring holes were filled with test shades. Color comparisons were performed by 5 evaluators using viewing booth. Color match was numerically rated from 1 (unacceptable mismatch) to 5 (perfect match). Color differences (deltaE*) were calculated based on spectroradiometer data. Fisher's PLSD intervals from ANOVA for comparison of means were calculated at the 0.05 level of significance. Results: Visual ratings and deltaE* values for single-composite test specimens vs. control specimens were compared with ratings for test shades vs. control shade in dual specimens. Differences between visual ratings (V_Diff%) and deltaE* values (I_Diff%) are listed in the table.

Comp/Shade	VDiff%	IDiff%
A/A1	-5	26
A/A2	-47	21
A/A3	-63	8
E/A1	132	61
E/A2	51	43
E/A3	1	8
F/A1	47	37
F/A2	13	46
F/A3	19	34
M/A1	64	21
M/A2	45	27
M/A3	52	37

Fisher's PLSD intervals (P<0.05) for comparisons of visual ratings among composites, shades and specimen types were 0.11, 0.09 and 0.08, respectively. Corresponding values for deltaE* values were 0.24, 0.21 and 0.17, respectively. Conclusions: Positive color shifting was recorded for composites E (least consistent by shade), F and M (most consistent by shade). Composites E and M exhibited the most pronounced V_Diff%, followed by composites F and A, respectively. Supported in part by Kuraray America.