Fatigue resistance of dentin bonds prepared with two- vs. three-step adhesives: Effect of carbodiimide.

The application of a cross-linker to demineralized dentin is reportedly effective at extending the durability of dentin bonds.
Objective: To compare the effect of a cross-linker pretreatment on the fatigue crack growth resistance of resin-dentin bonds prepared with a two- vs. three-step adhesive system.
Methods: Bonded interface Compact Tension (CT) specimens were prepared using commercial two- and three-step etch-and-rinse adhesives and compatible hybrid resin-composite. For the treated groups, adhesive bonding was preceded by a 1min application of an experimental carbodiimide (EDC) conditioner to the acid-etched dentin. The control groups received no such treatment. The fatigue crack growth resistance was examined after storage in artificial saliva at 37°C for 0, 3 and 6 months.
Results: There was no significant difference in the immediate fatigue crack growth resistance the control and EDC-treated groups at 0 months for either adhesive system. After 3 and 6 months of storage, the EDC-treated groups exhibited significantly greater (p≤0.05) fatigue crack growth resistance than the controls. Although the EDC treatment was equally effective in deterring degradation for both adhesives, bonds prepared with the three-step system exhibited the lowest resistance to fatigue crack growth overall.
Significance: An EDC treatment applied during dentin bonding could help maintain the durability of bonds prepared with two or three-step adhesive bonding systems.
(Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)