The purpose of this study was to compare the sealing ability of root canal filling by using 0.02 or 0.06 tapered gutta-percha master cones. Fifty six extracted single-root human premolars were selected and canals were prepared by RaCe 0.06 tapered rotary instruments. They were randomly divided into two experimental groups of 23 teeth in each and two control groups of 5 teeth in each. Then, canals were obturated with lateral condensation technique by using two different master points: a 0.06 tapered guttapercha (group A) and standardized (0.02) points (group B). Apical sealing ability in each group was evaluated by linear dye penetration method. Dye penetration was significantly greater in group A than group B. It was concluded that root canal filling with 0.02 tapered master points may be superior to 0.06 points.

Key words: Apical seal, root canal filling, different tapered master points, gutta-percha