Table 1. Protocols for experimental groups.

NaOCL, sodium hypochlorite; PUI, passive ultrasonic irrigation.

Experimental group	Irrigation protocol (repeated three times in each third of the root canal)	Final wash
NaOCl	5 mL of NaOCl 2.5% during instrumentation without PUI and then 5 mL remained in the canal without any activation.	10 mL of 2.5% NaOCl solution without PUI activation.
NaOCl + PUI	5 mL of NaOCl 2.5% during instrumentation without PUI and then 5 mL activated with PUI	10 mL of 2.5% NaOCl solution activated with PUI.
NaOCl gel	Filled with 2 mL of 3% NaOCl gel and irrigated with 10 mL of saline solution during instrumentation without PUI.	Filled with 2 mL of 3% NaOCl gel and irrigated with 10 mL of saline solution without PUI activation.
NaOCl gel + PUI	Filled with 1 mL of 3% NaOCl gel and irrigated with 10mL of saline solution during instrumentation without PUI and then filled with 1 mL of 3% NaOCl gel and irrigated with 10mL of saline solution activated with PUI	Filled with 2 mL of 3% NaOCl gel and irrigated with 10 mL of saline solution activated with PUI.