Efficacy of Apical Preparation With Passive Ultrasonic Irrigation in Reducing Intracanal Bacteria

Participants in this group underwent root canal shaping using a One Curve Mini #25/0.4 rotary file. After mechanical preparation, passive ultrasonic irrigation (PUI) was performed using a VDW Ultra device with an IRRI S 21/25 ultrasonic tip. Irrigation was activated with 3% sodium hypochlorite (NaOCl) in three 20-second cycles, using 1 ml per cycle. The ultrasonic tip was placed 2 mm short of the working length without contacting canal walls.

Participants in this group underwent root canal shaping using a One Curve Mini #35/0.4 rotary file. The same passive ultrasonic irrigation protocol was applied as in Arm 1, using 3% NaOCl in three 20-second cycles with 1 ml per cycle. The ultrasonic tip was positioned 2 mm short of the working length without contacting the canal walls.