Evaluating Postoperative Pain and Antibacterial Effect of Ultrasonic and 980 nm Diode Laser Combination

980 nm diode laser with optical fiber 200 µm (Lite medics, Italy) and power setting 1.2 watt in pulsed mode. The irradiation protocol will be a 5 sec. irradiation followed by a 10 sec. rest, which constituted one lasing cycle. The lasing cycle will be performed four times for each tooth.

After each file use, the root canal will be irrigated with 5ml of freshly prepared 2.5% sodium hypochlorite (NaOCl) solution (Alex. Deteregents and Chemical Co., Egypt) for 1 minute using a 31-gauge Navi-Tip flexible irrigating needle (Navi-Tip, Ultradent product, South Jourdan, UT). 5 ml of 17% EDTA (Colgate Oral Care Company, Waverly, Australia) for 1 min will be used for smear layer removal. 5 ml of saline solutio

980 nm diode laser with optical fiber 200 µm (Lite medics, Italy) and power setting 1.2 watt in pulsed mode. The irradiation protocol will be a 5 sec. irradiation followed by a 10 sec. rest, which constituted one lasing cycle. The lasing cycle will be performed four times for each tooth.

The needle will be operated using Satelec P5 Piezoelectric Ultrasonic Unit (Acteon, Mount Laurel, NJ, USA.) at power setting of 5. The stopper on the PiezoFlow needle will be set 1 mm short of binding in the canals, but not more than 75% of the WL. A syringe containing 5 mL of 2.5% NaOCl will be attached to the Piezoflow activation needle and the inactive needle will be inserted in the canal, and irrigant flow will be started before activation. During activation, the needle will be moved up and down passively in the canal