Composite resin containing silver for radiopacity bonds to the dentin surface of a resected and slightly concave root pretreated with a dentin bonding agent (Gluma). The bond strength between composite and apical dentin is about 18 MPa and is not affected by a preceding root canal filling with eugenol-containing sealer. Contamination with saliva or serum of the Gluma-treated dentin surface reduced the bond strength significantly. No reduction in bond strength is observed when the contamination of the surface is performed before Gluma-application. Microscopy of the borderline between composite and dentin as well as SEM of the composite surface adjacent to dentin revealed a good adaptation which presumably does not allow bacterial penetration.