Difference in opalescence of restorative materials by the illuminant.
OBJECTIVE
To determine the differences in the opalescence parameter (OP) of indirect and direct resin composites, veneer ceramics and bovine enamel relative to the CIE standard illuminants D65, A and F2.


METHODS
BelleGlass NG (indirect resin; 10 shades) and Estelite Sigma (direct resin; 12 shades), and 4 shades of veneer ceramics were investigated. Bovine enamel was used as a reference. Reflected and transmitted colors of specimens were measured relative to the illuminants D65, A and F2 with a reflection spectrophotometer. OP values relative to the three illuminants [OP(D65), OP(A) and OP(F2)], difference in OP (DeltaOP) and OP difference ratio relative to OP(D65) [DeltaOP/OP(D65)] by the change of illuminants were calculated. Within each restorative material, DeltaOP and DeltaOP/OP(D65) values were analyzed with two-way analysis of variance (ANOVA), with the fixed factors of the shade designation and the combination of illuminants (alpha=0.05).


RESULTS
DeltaOP and DeltaOP/OP(D65) values were influenced by the two factors within each restorative material based on two-way ANOVA. High opalescent materials showed higher DeltaOP values. OP(D65) was lower than OP(F2) and OP(A) values. Restorative materials showed lower DeltaOP/OP(D65) values than bovine enamel. Correlation coefficients between OP values relative to different illuminants were higher than 0.961 (P<0.01).


CONCLUSIONS
Direct resin composites instead of ceramics or indirect resin composites should be recommended in clinical dentistry since they showed similar opalescence properties as compared with natural tooth enamel.
Yu
Bin
B
Department of Dental Biomaterials Science, Dental Research Institute and BK 21 Program, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongro-gu, Seoul, Republic of Korea.
Lee
Yong-Keun
YK
D000818:Animals; D002417:Cattle; D003116:Color; D003124:Colorimetry / Q000592:standards; D003188:Composite Resins; D003743:Dental Enamel; D003793:Dental Restoration, Permanent; D008029:Lighting; D008689:Methacrylates; D012542:Scattering, Radiation
D003188:Composite Resins; C507124:Estelite sigma; D008689:Methacrylates; C110370:belleGlass