Root canal fillings performed with dentin bonding agent, gutta-percha, and epoxy resin sealer were observed by stereomicroscope. Fourteen palatal roots of extracted maxillary molars were used. Seven roots (group 1) were filled with gutta-percha, epoxy resin sealer, and dentin bonding agent. Seven (group 2) were filled with gutta-percha and epoxy resin sealer alone. The presence of these materials (gutta-percha, adhesive, cement, and a combination of these materials) and the number of voids present were evaluated in the apical, middle, and coronal thirds of the canals. In group 1, a combination of the three materials used was found to be the statistically most frequent case only in the apical third. No statistically significant difference was found between the overall number of voids present in the two groups. The resin-dentin-gutta-percha interface of roots from group 1 was observed by scanning electron microscopy: no statistically significant difference was found between apical and coronal sections regarding the presence of hybrid layer, penetration of resin into the dentinal tubules, or the presence of gaps in either the dentin-resin interface or the resin-gutta-percha interface.