Color stability of hybrid ionomers after accelerated aging.
OBJECTIVE
The color stability and surface roughness of three commercial hybrid ionomers were determined in vitro after accelerated aging. Three shades of each hybrid ionomer prepared in light-cured and dark-cured conditions were tested.


METHODS
Samples were aged in an artificial aging chamber by subjecting them to total ultraviolet light irradiation of 150 kJ/m2 over a period of 77 hours. Color (CIE LAB system) was measured before and after aging on a reflection spectrophotometer. Surface roughness was measured with a profilometer.


RESULTS
After accelerated aging, all samples became lighter. Photac-Fil Aplicap (ESPE-Premier, Norristown, PA) and Fuji II LC (GC America, Chicago, IL) also became less chromatic (less red and less yellow). Among the light-cured samples, Fuji II LC had the greatest change in color followed by Photac-Fil Aplicap and Vitremer (3M Dental Products, St Paul, MN). For the dark-cured samples, Fuji II LC had the greatest change in color followed by Vitremer and Photac-Fil Aplicap. There were no differences in delta E* between the two lightest shades, but the darker shades of each product showed the greatest changes in color. All samples became significantly rougher after aging.


CONCLUSIONS
Hybrid ionomers changed color significantly and perceptibly after in vitro accelerated aging. Surfaces became significantly rougher and showed evidence of cracking and degradation.
Davis
B A
BA
University of Texas-Houston Health Science Center, Dental Branch 77030-3402, USA.
Friedl
K H
KH
Powers
J M
JM
D000704:Analysis of Variance; D003116:Color; D003188:Composite Resins; D004355:Drug Stability; D005899:Glass Ionomer Cements / Q000737:chemistry*; D012117:Resins, Synthetic; D013499:Surface Properties; D013997:Time Factors
D003188:Composite Resins; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; C081144:Photac-Fil; D012117:Resins, Synthetic; C084550:Vitremer