Objective: The aim of this study was to determine the objective intrinsic color of a light-cured composite over a white and black backgrounds influence.
Methods: Flat samples in A3 dentin shade were prepared from Artemis fine-particle hybrid composite (Ivoclar-Vivadent AG, Schaan, FL) as disks of 10 mm diameter and thickness from 1 to 6 mm height, in a total of 5 sample groups. After polished, the samples were measured in the CIE L* a* b* system against black and white backings with a dental colorimeter (Ivoclar-Vivadente AG, Schaan). Based on the L* a* b* values the total color difference (DE) was calculated between the white and black backgrounds results. Mean and SD of DE are listed. Statistical analysis was conducted using One-way ANOVA and post hoc Tukey HSD-test (a = .05). Superscripts indicate statistically different subsets.
Results:
Sample Thickness [mm] | 1 | 2 | 3 | 4 | 5 | 6 |
DE n=5 | 14,0 (7.0)a | 3,5 (2,0)b
| 2,7 (1,5)b
| 1,2 (0,8)b
| 0,8 (0,6)b
| 0,6 (0,4)b |
The 1 mm composite samples showed DE values differing statistically significant to the others. DE decreased as a function of thickness. Depending on the reference DE values larger than 3.3 – 3.6 are perceived to be clinically different. This means that samples thinner than 3 mm had color values influenced by the background.
Conclusion: The composite restoration thickness plays a very important role concerning tooth color reproduction as long as the restoration is thinner than the threshold for the socalled “intrinsic” color. According to clinical criteria this threshold was between 2 – 3 mm for the materials investigated in this study.