This research investigates how the use of an etching gel containing silver nanoparticles (Ag NPs) affects the structural integrity and bonding strength at the “dentin-filling” and “enamel-filling” interfaces in permanent teeth with poor caries resistance in hard tissues. Teeth samples were taken from individuals aged 18 to 60 years, who underwent extractions for medical purposes. Adhesive systems from the IV and V generations were used for sealing, and both fluid and packable composites were selected as the filling materials. For metallographic analysis, the samples were cut perpendicular to the tooth axis, mechanically polished, and treated with concentrated orthophosphoric acid. Microscopic examinations were performed using both light and scanning electron microscopes. The findings show that the etching gel does not reduce the cohesive strength of the interfaces, even with the inclusion of silver nanoparticles.
