Comparison of 2 flushing methods used during passive ultrasonic irrigation of the root canal.

OBJECTIVE

To determine the effect of irrigation time on the removal of dentin debris from root canals irrigated with passive ultrasonic irrigation comparing 2 flushing methods.

METHOD AND MATERIALS: Root canals with a standardized groove in 1 canal wall, which was filled with dentin debris, were irrigated ultrasonically or with syringe irrigation. The quantity of dentin debris after irrigation was determined. In groups 1 to 4, the irrigant was activated by an ultrasonically activated file. In groups 1 and 2 (n = 20), the canals were flushed 3 or 1.5 minutes using a continuous flow of irrigant. In groups 3 and 4 (n = 20), the irrigation time was 1 or 3 minutes, and the canals were flushed 3 times by syringe irrigation (intermittent flushing method). In group 5 (n = 20), the root canals were flushed 3 times using syringe irrigation.

RESULTS

Significantly more dentin debris was removed when the irrigant was activated by ultrasound (P = .000). Significantly less dentin debris was removed when the root canals were irrigated with a continuous flow of irrigant for 1.5 minutes (P = .005).

CONCLUSIONS

Three minutes of ultrasonic irrigation with the intermittent flush technique or a continuous flow is as effective as 1 minute with the intermittent flush technique. The efficiency of the ultrasonic irrigation with a continuous flow is time dependent, 1.5 minutes being less efficient than 3 minutes.