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International Journal of Dentistry
Volume 2009, Article ID 313845, 7 pages
Research Article

Effect of Four Bleaching Regimens on Color Changes and Microhardness of Dental Nanofilled Composite

1Department of Restorative Dentistry, Araraquara School of Dentistry, University of São Paulo State, 1680 Humaitá Street 14801-903, Araraquara, SP, Brazil
2University Center Franciscano (UNIFRA), 1250 Andradas Street 97010-030, Santa Maria, RS, Brazil
3Physics Institute of São Carlos, University of São Paulo, 400 Trabalhador São Carlense Avenue 13560-970, São Carlos, SP, Brazil

Received 19 March 2009; Accepted 19 August 2009

Academic Editor: Toru Nikaido

Copyright © 2009 Simone Xavier Silva Costa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. The purpose of this study was to compare the color changes and microhardness of a nanocomposite after four bleaching regimens. Materials. Twenty-five specimens were made with a nanocomposite resin (Filtek Supreme XT). The specimens were divided into five groups equally : bleaching groups and control group, as follows: G1: artificial saliva at C; (control) G2: hydrogen peroxide (HP) at 7%; G3: hydrogen peroxide (HP) at 35%; G4: carbamide peroxide (CP) at 10%; G5: carbamide peroxide (CP) 35%. Color measurements were made with spectrophotometer using CIELAB color scale. The Vickers hardness (VHN) measurements were performed at the top surface. The data were analyzed with two-way Analysis of Variance. Results. E and VHN mean values into the groups were not statistically different, however, the VHN mean values before and after storage and bleaching showed statistically significant differences. Conclusion. Nanocomposite samples showed no significant alteration (color and microhardness) after bleaching. Thus, no replacement of restorations is required after bleaching.