Influence of Desensitising on Microtensile Bond Strength of Different Adhesives

Objectives: The aim of the study was to evaluate microtensile bond strength of a universal adhesive (Futurabond U, Voco GmbH, Germany) in self-etch and etch-and-rinse mode on human enamel and dentin compared with established systems. Additionally, the influence of an oxalate-containing desensitiser was evaluated. Methods: 180 human third molars were included. Standardised enamel and dentin specimens were prepared. 15 enamel and dentin samples each were assigned to one of the following experimental groups: Enamel groups: 1: Futurabond U, etch & rinse; 2: Futurabond U, self-etch; 3: Futurabond^® DC; 4: Solobond M. Dentin groups: 5: Futurabond U, etch & rinse; 6: Desensitizer, Futurabond U, etch & rinse; 7: Futurabond U, self-etch; 8: Desensitizer, Futurabond U, self-etch; 9: Futurabond DC; 10: Desensitizer, Futurabond^® DC; 11: Solobond M; 12: Desensitizer, Solobond M. The oxalate-containing desensitiser was applied in advance to the dentin samples. The adhesives were applied according to the manufacturer's instructions. After polymerization of the composite microtensile bond strength values were determined using a universal testing machine (Zwick Z 005). Results: Significantly higher values could be found for Futurabond U in the etch-and-rinse mode (21.45 MPa) compared to the self-etch mode (16.09 MPa) on enamel. Compared to the other two adhesives, no significant differences could be detected. The additional application of the oxalate-containing desensitiser in the case of dentin samples did not show any significant difference in the etch-and-rinse mode. For groups in self-etch mode, the desensitiser application resulted in significantly reduced tensile bond strength values compared to groups without desensitiser application. Conclusions: Regarding the limitations of an in-vitro study, it can be concluded that Futurabond U has very promising results on enamel and dentin compared to the established adhesives. The influence of an oxalate-containing desensitiser on the adhesion is only visible in the case of the self-etch application mode. Keywords: desensitising, microtensile bond strength, universal adhesive, self-etch, etch-and-rinse