Objectives: The purpose of this study was to evaluate the tensile bond strength (TBS) of restorative systems (adhesives / low shrinkage and conventional composites) to dentin.
Methods: Two low-shrinkage composites (Filtek LS, 3M ESPE and Aelite LS, Bisco Inc.), two composites with conventional composition (Heliomolar and Tetric N-Ceram, Ivoclar Vivadent) and the adhesive systems of their respective manufacturers (Silorane, One-Step Plus, Excite and Tetric N-Bond) were evaluated. Twenty-eight extracted human teeth were assigned to 4 groups (n=7). Dentin was wet-abraded with SiC paper (600-grit) and the adhesives were applied according to manufacturers' instructions. Composite blocks of approximately 6 mm high were built up on bonded surfaces. Teeth were sectioned into bonded beams after 24h and stored in artificial saliva. The beams from each tooth were assigned to be tested at 24 hs and one year. MicroTBS was evaluated using EZ-Test machine (Shimadzu). The data were analyzed using two-way ANOVA and Tukey test (p<0.05). Results: TBS means (MPa ± SD) are summarized in the table below:
TBS
| ||
Adhesive/Composite
| 24 hours
| 1 year |
Excite/Heliomolar
| 51.6 (6.8) Aa
| 23.1 (4.4) Cb |
One-Step Plus/Aelite LS
| 48.4 (3.9) Aa
| 27.8 (3.2) Bb |
N-Bond/Tetric N Ceram
| 47.0 (2.9) Aa
| 28.5 (2.7) Bb |
Silorane/Filtek LS
| 37.3 (4.3) Ba
| 36.1 (2.1) Aa
|
Different upper and lower case letters show statistical differences within columns and rows, respectively.
| ||
Conclusion: The results showed that the storage for one year affected TBS of restorative systems, except for Filtek LS/Silorane.
Supported by FAPESP # 2009/51454-6.