Methods: Three nanofilled resin composites were used: Venus Diamond (Heraeus), Filtek Supreme Ultra (3M), and Esthet X HD (DENTSPLY). Two different bleaching agents were used: Daily (16% carbamide peroxide) and Weekly (37.5% hydrogen peroxide). Samples were polymerized (LED) for 20s. The samples were whitened for 3 weeks (n=6). Daily bleaching was applied one hour twice daily (stored H2O, 37C). Weekly bleaching was applied for once a week, five times during 8 minutes. Bleaching was applied only on one side of the samples (other side was the control group). The surface roughness (Ra, µm) was evaluated using Mitutoyo Roughness Tester. Measurements were performed on three different areas of each specimen and the average values were calculated (ANOVA, Tukey test p<0.05).
Results: The table below shows mean Ra values and standard deviations (p<0.05) of the three materials after the various bleaching sessions.
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Resin |
Control |
Week 1 |
Week 2 |
Week 3 |
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Daily |
Weekly |
Daily |
Weekly |
Daily |
Weekly |
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Venus |
0.345 ±0.188 |
0.247 ±0.097 |
0.278 ±0.072 |
0.244 ±0.066 |
0.343 ±0.204 |
0.344 ±0.062 |
0.238 ±0.133 |
Filtek |
0.27 ±0.122 |
0.286 ±0.086 |
0.138 ±0.082 |
0.427 ±0.27 |
0.392 ±0.045 |
0.172 ±0.058 |
0.418 ±0.256 |
Esthet X |
0.309 ±0.113 |
0.284 ±0.129 |
0.628 ±0.152 |
0.47 ±0.23 |
0.374 ±0.237 |
0.221 ±0.081 |
0.396 ±0.113 |
Conclusions: At the 0.05 level, factor Week are not significantly different, but factor Resin and the interactions between Week, Resin and Bleaching agent are significant.