Assessment of changes in color and color parameters of light-cured composite resin after alternative polymerization methods.

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 Lab 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 (α=.05).

RESULTS

There were no significant differences in total color change (ΔEab) among the polymerization groups (P>.05). However, the lowest color change (ΔEab) value was 3.3 in LED and autoclave; the highest color change (ΔEab) value was 4.6 in HQTH. For all groups, CIE L, Cab and avalues 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 (ΔEab⩾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.