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.