Single-rooted human teeth were assigned to 6 groups. The teeth in the 6 groups were pre-treated with EDTA, IKI or NaCl and obturated with gutta-percha/epoxy sealer or acrylic-based sealer and core, respectively. Two discs were cut from each tooth and the bond strength between the root filling material and dentin was determined using a push-out test. The results were statistically evaluated using the Kolmogorov-Smirnov test.

Acrylic-based root fillings obtained higher bond strengths than those with gutta-percha /epoxy resin when NaCl was used for irrigation. Pre-treatment with EDTA yielded weaker bonds to dentin for the acrylic-based root fillings. The use of IKI resulted in lower bond strengths for the acrylic based root fillings whereas IKI improved the bond strength between dentin and gutta-percha/epoxy resin sealer. It is speculated that the improved bonding of the epoxy to dentin after IKI is due to cross binding between oxidized sites on dentinal collagen and the epoxy groups in the sealer.