Diagnostic procedures to include history taking and clinical and radiographic examination with all findings being recorded in patient's notes.
• A prolonged exaggerated response (more than 10 seconds) to a cold pulp sensibility test and a positive response to the electric pulp tester will be considered evidence for irreversible pulpitis.
Patients will be asked to rate their pre-treatment pain on a visual analogue scale from 0 to 10.
Patients with moderate pain will be selected, VAS score (4 - 6).
* ANESTHESIA Patients receive 2 cartridges of 2% Articaine with 1:80000 epinephrine in an Inferior Alveolar Nerve Block Injection
* Access opening, isolation and first rinse with NaOCl After access preparation, each tooth will be isolated using rubber dam. Patients will be randomly assigned to either of the following groups: 3% NaOCl or 6% NaOCl. The pulp chamber will be filled with 2mL irrigant for 2 min followed by saline irrigation.
* Hand Instrumentation The patency of canals will be established and an initial glidepath be prepared using size 10 and 15 K-files (Mani, Mani Inc., Tochigi, Japan)
* WORKING LENGHT WL will be determined using apex locator (DentaPort ZX, J.Morita USA) and confirmed radiographically to be 1 mm short of the radiographic apex.
* ROTARY INSTRUMENTATION Mechanical prep using a Niti rotary system (Protaper Universal, Dentsply Sirona) in a torque-controlled endodontic motor (X-Smart plus, Dentsply Maillefer) according to the manufacturer's sequence and recommendations of speed and torque. Canal prep with S1 and SX instruments in a crown-down sequence to shape the coronal two-thirds of canal.
* APICAL PREPARATION Apical patency will be maintained with a size 10 K file before each rotary-instrument change.The apical preparation will be done using S1, S2, F1 or F2 up to WL corresponding to tip size of F1 or F2.
* IRRIGATION
* Between instruments, the root canals will be irrigated with 2 mL of either 3% or 6% NaOCl with a 30G x 25mm side-perforated needle (Medic Endo Irrigation Needles, HDS).
* The tip of the needle will be kept 4mm short of WL. The needle will be repeatedly moved up and down in order to prevent locking in the canals.
* Volume of irrigant use after every instrumentation - 2ml
* Total volume of NaOCl used per canal - 8-10ml , per Tooth - 24 - 30 ml
* After NaOCl, canals will be flushed with 5ml normal saline irrigation.
* Smear layer will be removed by irrigation with 17% EDTA, (EDTA; Glycle File Prep, Dentsply Maillefer) followed by 5 mL normal saline irrigation.
* DRYING CANALS At the same visit, the root canals will be dried with paper points (GAPADENT Absorbent paper points)
* OBTURATION Shall be filled with matched size gutta-percha cones (Meta Biomed Co, Korea) and sealar (Endoplus Root Canal Sealer 13,5g President Dental Germany) using the single cone technique.
* Sealed with Temporary restoration (Cavit, 3M ESPE, Germany) Patients will receive a rescue bag of 10 Ibuprofen in case they have pain with instructions for ondemand use.
