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T. PLEIN, R. LANG, M. ROSENTRITT, and G. HANDEL, University of Regensburg, Germany Objectives: The influence of bleaching materials on enamel is of major concern in the clinical application. In this in vitro study the effect of carbamide-peroxide and H2O2 bleaching materials on the color behavior and the superficial roughness of bovine enamel was tested.
Methods: 25 freshly extracted bovine lower anterior teeth were divided in 5 groups. 3 groups were treated with nite white excel 2 11% and 16% carbamide peroxide (DiscusDental, USA) and White Smile 10% carbamide peroxide (White Smile, G) 9 days for 5 hours. The other groups were treated with two Daywhite two 7.5% and 9.5% hydrogen peroxide (Discus dental, USA) 9 days for 30 minutes two times a day. Discoloration (D
E*) and roughness (Ra) was investigated in the beginning and after each bleaching using a reflection spectrophotometer (CM 3500d, Minolta, G) and a perthometer (S6P, Perthen, G). Differences in color and roughness referring to the baseline measurement were calculated. Statistics were performed using the Mann-Whitney U-Test (p£
0.05). Medians of color differences and roughness after bleaching are listed.
Results:
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Bleaching systems |
|
Mean D
E/D
Ra(µm) |
Nite 11% |
Nite 16% |
Daywhite 7,5% |
Daywhite 9,5% |
White Smile |
|
1. bleaching |
3.9/0.20 |
8.7/0.16 |
2.4/0.27 |
2.9/0.33 |
9.8/0.49 |
|
3. bleaching |
4.0/0.22 |
8.3/0.20 |
4.8/0.22 |
5.0/0.38 |
6.6/0.42 |
|
6. bleaching |
4.5/0.22 |
8.6/0.18 |
11.2/0.31 |
6.5/0.37 |
5.8/0.31 |
|
9. bleaching |
8.5/0.44 |
9.7/0.43 |
8.6/0.24 |
7.5/0.28 |
15.3/0.40 |
Conclusions: The increase of superficial roughness was similar regarding both systems. A low concentration of carbamide-peroxide and H2O2 achieves equivalent discoloration.
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