Abstract :
Color changes after polymerization and aging of dental resin composites are perceptible. If
these color changes can be predicted by the shade of material before polymerization or
clinical use, color matching of composites with teeth would be improved. The objectives
were to measure the correlations among the color coordinates (CIE L∗, a∗ and b∗) of dental
resin composites and the changes in color ( E∗ab) and color parameters ( L∗, C∗ab, and
H∗ab) after polymerization (PO) and thermocycling (TC), and to determine whether the
range of color coordinates influenced these correlations. Color of two resin composites (26
shades) was measured before and after PO, and after TC with a reflection
spectrophotometer. Regression analyses were performed among the color coordinates and
the changes in color and color parameters after PO and TC. After PO, E∗ab was correlated
with CIE L∗ value measured after PO, and CIE a∗ and b∗ values measured before PO
(p<0.01). After TC, E∗ab was correlated with CIE b∗, a∗, and L∗ measured after PO (p<0.01).
Correlations among the color coordinates and the changes in color parameters after PO or
TC varied, but were generally significant (p<0.01). Multiple regression analyses showed
that E∗ab values after PO and TC were mainly influenced by CIE L∗ after PO (multiple
r = 0.87 after PO and 0.58 after TC). Correlations were also influenced by the range of color
coordinates. Within the limit of this study, shade of resin composites significantly
influenced the changes in color and color coordinates after PO and TC. Light shades (high
CIE L∗ shades measured after polymerization) showed small color changes after
polymerization and thermocycling. C 2005 Springer Science + Business Media, Inc.
