A polydimethylsiloxane-based sealer (GuttaFlow) was used for filling single-rooted teeth with four obturation techniques. Prefitted gutta-percha master-cones were employed in groups 1 to 3 with backfilling of the sealer. Apical third of the roots were first filled with GuttaFlow, and sealer-coated master cones were seated with up-and-down motion (group 1) or rotated to place (group 2). Master-cones were used as carriers for introducing GuttaFlow into the canals (group 3). Canals were filled with GuttaFlow without master-cones (group 4). Canals were filled with AH Plus/gutta-percha using warm vertical compaction (control group 5). All obturated canals were tested for leakage after 1, 6, and 12 weeks using the fluid filtration technique. All groups exhibited equivalent seal regardless of time except for more extensive leakage in group 3. The use of GuttaFlow with a single gutta-percha master cone creates an apical seal that is equivalent to that produced with gutta-percha/AH Plus sealer using warm vertical compaction.