After confirming the eligibility , the patients will be informed about the study design, the clinical procedure involved, and the associated risks.They will be  ensured that root canal treatment will be performed regardless of whether they decided to participate in the study or not. Once the patient agreed to participate, verbal and written consent will be obtained, and the patient will be randomly assigned to 1 of the 4 designated groups. Randomization will be developed to eliminate any bias on the part of the investigators and to balance the number of patients between the treatment protocol types.The clinical and CBCT findings will be verified before the Root Canal Treatment.

Clinical Procedure

After the administration of local anesthesia (Lignocaine HCl with 2% adrenaline 1:80,000 (Lignox 2% A,Indoco Warren) caries will be excavated, and the access cavity will be  prepared under rubber dam isolation. The working length will be determined with the help of an electronic apex locator (Coltene Whaledent Private LTD) and will be confirmed with straight and angled radiographs. Then canals will be prepared using the step-back technique with 0.02% taper ISO stainless steel hand files.The apical preparation will be done with No.25,0.04% ; No.25,0.06% ; No.30,0.04% ; No.30,0.06% rotary files ( Hyflex CM) in groups A,B,C,D respectively and it will be accompanied by irrigation with 5 mL of  5.25% NaOCl (Prime Dental product Private Ltd, INDIA)  after each instrumentation cycle. Canal patency will be  ensured by passing a #10 stainless steel file approximately 0.5 to 1.0 mm beyond the working length. After enlarging, the canals will be  irrigated with 5 mL  of 17% EDTA for 1 minute. After drying with sterile absorbent points, the canals will be  filled with paste made by mixing calcium hydroxide powder  with 2% chlorhexidine liquid  using a lentulo spiral. The tooth will  then temporarily restored with Intermediate Restorative Material (Prime Dental product Private Ltd, INDIA).  The patient will be recalled after 1 week. At the next appointment, the paste will be removed with the help of XP Endo Finisher and copious irrigation with 5.25% NaOCl followed by a final rinse of 5.0 mL 17% EDTA. If the patient is asympomatic then the canals be obturated with gutta-percha and bioceramic sealer(CERASEAL, MetaBiomed,Europe) using lateral condensation technique, if the patient is symptomatic the canals will be cleaned and shaped and the intracanal medicament will be placed again and patient will be recalled again after 1 week . After obturation, the access cavity will be  restored. An immediate postoperative radiograph will be taken using preset exposure parameters and will be processed manually. Follow-up examinations will be performed after 6  months and it consists of history taking and clinical and CBCT examination.