Maxi i probe

For PUI groups (PUI + MIT and PUI + CIT), the tooth was irrigated using a 30-G side vented Maxi-i-Probe (DENTSPLY Maillefer, Tulsa Oklahoma) needle with 5 mL of 3% NaOCl. The NaOCl was activated SATELEC Sonofile (ACTEON Inc.) K-file ultrasonic tip size 15 for 1 min in each canal at a power setting of 4 using a ProUltra Piezo Ultrasonic unit (ProUltra, Dentsply Tulsa Dental). The ultrasonic file was taken 2 mm short of the root canal length. The canals were irrigated with 5 mL of 3% NaOCl. After, the canals were rinsed with 5 mL of 17% EDTA for 1 min and then rinsed off with 5 mL 3% NaOCl. This irrigation procedure was repeated twice for a total of 3 min 17% EDTA action. The canals were rinsed off with 5 mL of 3% NaOCl and inactivated with 5 mL of sterile 0.5% sodium thiosulfate for 1 min. Lastly, the canals were flushed with 5 mL of endotoxin-free water (LAL water, LONZA, Walkersville). After the PUI protocol, a second LPS sample (s2) was collected from the root canals as previously described.

Root canals were rinsed with 10 mL 1.5% NaOCl using a 5- mL disposable plastic syringe and 30 G SVN (Maxi-i-probe, Dentsply, Rinn, IL, USA). The needle was inserted passively up to 1 mm short of the WL with a flow rate of approximately 5 mL/min. During irrigation, the needle was constantly moved up and down within the apical third.
The irrigants temperature, flow rate, volume and activation time were standardized for all groups. Rubber stoppers were placed on the XPF, IrriSafe ultrasonic tip and the needle at the required length to ensure length control. In all groups, a final flush using 2 mL 17% EDTA was used. NaOCl solution used in all groups was warmed to 37 °C prior to the application to allow the XPF to work optimally at the austenite phase.

The specimens were rinsed with 10 mL 1.5% NaOCl using a syringe and 30 G SVN (Maxi-i-probe, Dentsply, Rinn, IL, USA) placed 1 mm from the WL with a flow rate of approximately 5 mL/min. XPF file (size 25, 0.00 taper) (FKG, LaChaux-de-faund, Switzerland) was used with an endodontic motor (X‐Smart, Dentsply‐Maillefer, Ballaigues, Switzerland) at 800 rpm and 1 Ncm torque according to the manufacturer’s instructions [11 ]. The file was inserted 1 mm shorter than the WL which was adjusted using the plastic tube to fix the rubber stopper and operated for 60 s using slow and gentle 7–8 mm lengthwise in‐and‐out movements. Each file was used for one canal in order to prevent interfering with the debris extrusion results.