Optimized Root Canal Instrumentation

Root canal instrumentation was performed on the assigned patients utilizing 21 mm XP-endo Shaper files. After access cavity preparation, the canal patency was inspected using a #10 K-file, and if desired, a glide path until a #15 K-file was prepared. The root canals were loaded with 2 mL of 2.5% NaOCl before the XP-endo Shaper file was inserted passively until resistance was reached. After retracting the tip coronally, the endomotor was powered at 800 rpm and 1 Ncm torque, and the file was reintroduced. The file was used 4–5 times toward the WL with delicate vertical strokes. When the WL was achieved, the file was retracted and cleaned, apical patency was ascertained with the #15 K-file, the canal was irrigated again with 4 mL of 2.5% NaOCl, and the file was used for an additional 15 thrusts to the WL, designating instrumentation fulfilment, accompanied by irrigating the canal with 4 mL of 2.5% NaOCl, as per manufacturer’s instructions. Eventually, the canals were irrigated with 2 mL of 17% EDTA and normal saline.