The long-term sealing ability of an epoxy resin root canal sealer used with five gutta percha obturation techniques

The aim of the present study was to evaluate the long-term sealing ability (both apical and coronal) of an epoxy resin root canal sealer (AH26) when used with different gutta-percha obturation techniques.

Straight single-rooted teeth with mature apices were divided into 10 groups of 75 teeth and one group of 40 control teeth. Root canals were prepared according to the crown-down/step-back technique and using both 2.5% sodium hypochlorite and an EDTA paste. Root canals were obturated using cold lateral condensation, warm vertical condensation and hybrid condensation of gutta-percha; and with Thermafil and Soft-Core obturators. AH26 was used as the sealer in all cases. After root canal filling, each group was divided into five individual groups of 15 teeth. The first group of 15 teeth was kept for 1 day, the second for 1 week, the third for 4 months, the fourth for 6 months and the fifth for 12 months at 37 degrees C in vacutainers in 80% relative humidity. The teeth were immersed in India ink for 90 h, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification.

Leakage occurred whatever filling technique was combined with AH26. The number of teeth with gross leakage increased with time up to 4 months, but did not appear to increase between 6 and 12 months storage. The degree of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all four other gutta-percha obturation techniques. Up to 4 months the degree of coronal leakage and the number of leaking teeth in the Thermafil groups was significantly higher than the other gutta-percha obturation techniques, except for Soft-Core. In the Soft-Core obturator groups the degree of coronal leakage and the number of leaking teeth was significantly higher than the other gutta-percha obturation techniques, except for Thermafil at all evaluation times.

The hybrid gutta-percha condensation technique was superior to the other four obturation techniques in respect of apical leakage. Coronal leakage was significantly greater during the first 4 months for the Thermafil system as compared to the three condensation techniques; coronal leakage was significantly greater at all time periods for the Soft-Core system. There were no significant differences between the Thermafil and the Soft-core system.