Color and translucency of resin composite color modifiers

Objectives:  Little information is available on the optical properties of opaque shades and modifiers of resin composites.  The purpose of this study was to evaluate the color and translucency of resin composite modifiers.

Methods:  Specimen mold (2 mm thick) was used for making standardized specimens (n=39) of opaque shades and color modifiers (CM).  The mold was filled with resin composite materials (Creative Colors, REnamel, Cosmedent) and covered with clear celluloid strips on the top and bottom.  The resin was cured using an Optilux 401 (Demetron, Danbury) for 60s on each side.  After light curing, the color of each of the materials (n=3) was measured by a spectrophotometer, ES (Easyshade, Vident) on backings of black and white.  The Easyshade measures color using CIE L*C*H* but also provides an interpolated Vita 3D and Classical tab number.  The L*C*H* values were converted to CIELAB (L*, a* and b*) and the translucency parameter was calculated as [(L*_b-L*_w)² + (a*_b-a*_w)² + (b*_b-b*_w)²] ^½.  The ΔTP is expressed relative to the TP of shade A2 and A2Opaque.

Results:

		Vita 3D & Classical Tabs		(TPA2 - TPCM)	(TPA2O - TPCM)
		(Black background)	(White background)
CC Color	Grey	NA (C4)	5M1  (C4)	-26.31	27.53
	Violet	NA  (C4)	NA  (C4)	19.21	73.05
	Dark Brown	5M3  (C4)	5M3  (C4)	24.80	78.64
	Light Brown	NA  (C4)	NA  (A4)	-98.60	-44.76
	Honey Yellow	NA (A4)	NA (A3.5)	-91.49	-37.65
CC Opaque	Pink	5M3 (C4)	5M3 (C4)	5.50	59.34
	White	5M3 (C4)	5M3 (C4)	4.10	57.95
REnamel Microfilled	LO	1.5M2.5 (A2)	1.5M2 (A2)	22.19	76.03
	IL	1M1 (B1)	0.5M2.5 (A1)	19.28	73.12
	ID	2.5M1 (D2)	2R2 (A2)	19.09	72.93
	IM	2M1 (B1)	0.5M2.5 (A1)	-3.9	49.94

Conclusions:  TP of opaque shades and modifiers of resin composites was found to be highly varied.  The intense color and opaqueness presented a technical challenge.