Color stability of resin-based filling materials after aging when cured with plasma or halogen light

The influence of curing devices and curing times on the color stability of filling resins was investigated by measuring the CIE-Laboratory-values after performing dry storage, water storage, and a Suntest (EN ISO 7491). Eight samples each of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) were light cured by using Translux Energy (TE) for 20, 40 or 60 s, or by using Apollo 95E (AP) for 3, 10 or 20 s. Minor color changes occurred for all dry stored materials, devices and curing times. The TE-cured, water-stored samples behaved similarly to the dry-stored ones, but the samples cured with AP revealed very strong color changes, mainly because of a drastic bleaching process. The bleaching of DU was significantly less than that of the other materials, but a strong white shift occurred. CH, DE, and DU showed very little (and even acceptable) discolorations after the Suntest when TE-cured. DY showed a drastically discoloration. All samples cured using AP drastically bleached and shifted to white for DU and DY but to dark for DE. In conclusion, the extent of discoloration depends on (i) the material, (ii) the test method, (iii) curing time, and (iv) the curing device. The halogen light-cured samples performed best.