Assessment of Changes in Color and Color Parameters of Light-Cured Composite Resin after Alternative Polymerization Methods

Abstract

Objective: To examine the amount of change in color and color parameters of a composite resin (Filtek P60) polymerized by five different polymerization methods. Methods: A Teflon mold (6mm in diameter, 2mm in height) was used to prepare the composite resin discs (n=10). G1: Polymerization with inlay oven; G2: Polymerization with HQTH and autoclave; G3: Polymerization with LED and autoclave; G4: Polymerization with HQTH; G5: Polymerization with LED. Colorimetric values of the specimens before and after polymerization were measured using a spectrophotometer. The CIE L*a*b color system was used for the determination of color difference. Analysis of variance (ANOVA) was used to analyze the data for significant differences. Tukey's HSD test and paired two-tailed tests were used to perform multiple comparisons (a=.05). Results: There were no significant differences in total color change (δE*ab) among the polymerization groups (P>.05). However, the lowest color change (δE*ab) value was 3.3 in LED and autoclave; the highest color change (δE*ab) value was 4.6 in HQTH. For all groups, CIE L*, C*ab and a*values decreased after polymerization (P<.05). The highest δb* and δC*ab values were observed in specimens polymerized in an inlay oven (P<.05). Conclusions: Composite resin material showed color changes above the clinically accepted value in all study groups (δE*ab=3.3). All specimens became darker during investigation (δL*< 0). Specimens polymerized with inlay oven presented the highest δb* values which means less yellow color in specimens.