Academy of Dental Materials Annual Meeting location:Portland, Oregon, USA date:October 29-31, 2009
Objectives: To evaluate the fatigue resistance of adhesives bonded to dentin, in comparison to their micro-tensile bond strength (µTBS).
Materials and Methods: The bonding effectiveness of three adhesives (3-step etch-and-rinse adhesive or 3-E&RA OptiBond FL, 2-step self-etch adhesive or 2 SEA Clearfil SE, and 1-step self-etch adhesive or 1-SEA G-Bond) was measured by means of a micro-tensile fatigue resistance (µTFR) and µTBS protocol Preparation and test set-up of the micro-specimens for both µTFR and µTBS were identical. In fatigue, specimens were tested in a wide range of selected loads at 2 Hz and at 10 Hz until failure or until 104 cycles were reached. At 2 Hz, the µTFR was measured after 1 week and 3 months of water storage. The µTFR was determined (in MPa) using a logistic regression model. Two-way ANOVA and Tukey HSD multiple comparisons test were used to determine statistica differences in µTBS.
Conclusions: The 3-E&RA performed better in terms of bonding effectiveness irrespective of the test conditions applied. The µTBS test has proven once more to be a reliable in vitro test, providing results that are comparable to those of a alleged more clinically relevant fatigue test. The load frequency and water storage time are important parameters to be defined in the fatigue test set-up.