Color stability of experimental composites containing different photoinitiators.

OBJECTIVES

To evaluate the color stability (ΔE) of experimental composites containing different photoinitiators when submitted to accelerated artificial ageing (AAA).

MATERIAL AND METHODS

Thirty test specimens were made in a Teflon matrix (8mm×2mm), using an experimental composite (n=10) with the same monomer composition and particle size, but varying photoinitiator used: Group CQ (0.4% Camphorquinone), Group PPD (0.4% 1-Phenyl-1,2 Propanodione) and Group CQ+PPD (0.2% CQ+0.2% PPD). The samples were light activated (QTH - Ultralux - Dabi Atlante - 40s) and polished before performing the initial color readouts (EasyShade - Vita). Next, they were submitted to AAA for 300h, after which final color readouts were made.

RESULTS

The results (1-way ANOVA - Tukey - p<0.05) demonstrated that all the groups presented color alteration above the clinically acceptable level (ΔE≥3.3), however, with no statistically significant difference among them (p>0.05). Analysis of Δb demonstrated increase in the values of this coordinate, indicating yellowing in all groups.

CONCLUSIONS

It was concluded that the type of photoinitiator, which presented a tendency towards yellowing, did not interfere in the color stability of composites submitted to AAA.

CLINICAL SIGNIFICANCE

Alternative photoinitiators have been extensively studied since Camphorquinone presents a yellowish color, which compromises the aesthetic performance of composites, especially the lighter-shade ones.