The Effect of Different Sodium Hypochlorite Concentrations and Activation Techniques on Postoperative Pain

EDDY is a sonic irrigation activation system operating at 6,000 Hz frequency with a flexible polyamide tip (25/04). In endodontic procedures, the EDDY tip is inserted 2 mm short of the working length into the root canal and activated for 20 seconds in three consecutive cycles. The sonic activation enhances irrigant agitation through cavitation and acoustic streaming, improving cleaning efficacy within the root canal system, especially in curved canals. The device does not contact dentin walls, reducing the risk of iatrogenic damage. In this study, EDDY was used to activate sodium hypochlorite solutions of either 2.5% or 5.25% concentration depending on the assigned group.

Passive Ultrasonic Irrigation (PUI) involves the use of an ultrasonically activated file or tip inserted into the root canal 2 mm short of the working length, without contacting the dentinal walls. The ultrasonic tip is operated in a non-cutting, passive manner to generate acoustic streaming and cavitation within the irrigant. In this study, after initial irrigation with 2 mL of sodium hypochlorite (either 2.5% or 5.25%, depending on the group), ultrasonic activation was performed for 20 seconds in three consecutive cycles. Each activation was followed by 1 mL NaOCl irrigation. This method is designed to enhance the penetration and effectiveness of irrigants, especially in anatomically complex areas of the root canal system.