Accelerated Aging Dependent Changes In Color Of Resin Composites

Objective: To evaluate the accelerated aging effects on color of different composite resins.

Method: Shades were selected from two flowable composites, A1, A3, and White (WH), Filtek Supreme Ultra Flowable/3M ESPE (FSU); A1, A3 and Bleach (BL), Tetric EvoFlow/Ivoclar Vivadent (TEF), and A1, A3, and B1 micro-hybrid control (Filtek Z250/3M ESPE). Disc shaped specimens (10 mm X 2 mm, n=60) were polymerized using a halogen curing light (Demetron 501, Kerr/Demetron) for 40 seconds. Specimens were finished using 400-grit SiC paper and polished with a one-step polisher (PoGo, Dentsply/Caulk) for 40 seconds. Color measurements were taken at baseline (after 24 hour-storage in distilled water at 37°C) using a spectrophometer (Color-Eye 7000, GretagMacbeth) and after exposure to accelerated aging (150 kJ/m²) in a Weather-ometer (Ci35A, Atlas). Means and standard deviations were determined. The data were analyzed by analysis of variance. Fisher's PLSD intervals at a 0.05 level of significance were determined for mean Lab and ΔE values.

Result: Color parameter changes are listed in the following table,(composite product/shade):

	TEF/A1	TEF/A3	TEF/BL	FSU/A1	FSU/A3	FSU/WH	Z250/A1	Z250/A3	Z250/B1
ΔL*	-1.0(0.3)	-0.6(0.4)	-0.3(1.2)	1.1(0.4)	0.4(0.4)	2.0(0.7)	1.3(0.2)	1.8(0.7)	3.2(0.2)
Δa*	-0.2(0.1)	0.2(0.1)	-0.4(0.1)	-0.3(0.0)	-0.6(0.2)	-0.2(0.3)	-0.6(0.0)	-0.5(0.0)	0.4(0.0)
Δb*	0.4(0.4)	-0.6(0.2)	-0.5(0.4)	-3.9(0.3)	-3.4(0.9)	-4.6(0.6)	-0.8(0.2)	-0.2(0.7)	0.1(0.2)
ΔE*	1.2(0.3)	0.9(0.3)	1.3(0.3)	4.0(0.2)	3.5(0.8)	5.1(0.8)	1.6(0.2)	2.0(0.7)	3.2(0.2)

Fisher's PLSD intervals for comparisons among products and shades were 0.4 for ΔL and ΔE while the corresponding values for  Δa values were 0.09. The data showed significant ΔE* and ΔL* main effects for composite product and shades (p<0.001) and interactions (p=0.008 and p=0.03), respectively. 

Conclusion: The effects of accelerated aging on color of resin flowable composites are dependent on composite product and shade selection. Tetric EvoFlow displayed the smallest aging-dependent color shift followed by Filtek Z250 and Filtek Supreme Ultra Flowable.

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