Abstract Introduction The aim of this study was to evaluate the retreatment efficacy and amount of residual sealer in a single canal filled with either EndoSequence BC (Brasseler, Savannah, GA) or AH Plus (Dentsply DeTrey, Konstanz, Germany). Methods Canal obturation with gutta-percha and sealer was performed in 28 human teeth using the continuous wave technique. Group 1 ( n  = 13) used AH Plus sealer, and group 2 ( n  = 15) used EndoSequence BC sealer. After 7 days, the root fillings were removed using Gates Glidden drills and a nickel-titanium rotary system. Retreatment time was measured in seconds. Canal cleanliness was examined by scanning electron microscopy. The remaining debris in the canal space and penetration into dentinal tubules were evaluated by confocal microscopy. Retreatment time was compared using the Student t test, and differences in sealer penetration and remaining debris between the groups were analyzed using the Mann-Whitney U test ( P  < .05). Results There was no significant difference between the 2 groups in the amount of dentin penetration, amount of debris, or retreatment time. With respect to penetration depth, the AH Plus group showed a slightly higher percentage than the BC group, with a significant difference only in the portion 6 mm from the apex ( P  < .05). Scanning electron microscopic images showed significant debris remaining on canal walls in both groups, whereas canal patency in retreatment was achieved in every specimen. Conclusions The present study shows that EndoSequence BC sealer and AH Plus sealer have similar efficacy in dentin penetration and retreatment efficacy.