To evaluate the apical sealing ability of different obturationtechniques in oval-root canals.

After root canals shaping with Mtwo instruments, 42 premolars with oval-root canals were randomly divided into 3 groups of 14 teeth each. Group A wereobturated by single-cone technique. Group B were obturated by modified continuous wave condensation technique. Group A were obturated by lateral condensation. IRoot SP was used as root canal sealer in all groups. The apical leakage was evaluated by dye penetration method and transparent teeth technique.

Mean depth of leakage was (1.34 ± 0.33) mm for group A, (0.84 ± 0.40) mm for group B and (1.13 ± 0.33) mm for group C. There was significant difference between group A and group B (P = 0.004). while no significant difference was found between group A and group C (P = 0.198), group C and group C (P = 0.072).

The oval-root canalobturated withmodified continuous wave condensation withi Root SP as sealercan get a goodapical sealing ability.