Irreversible pulpitis on mandibular first molar. Long,calcified and S shape root canal system made this procedure a rather challenging one. Endodontic procedure instrumentation has been performed with Mani stainless K files and ProTaper Universal (Dentsply). Chelator: RC Prep. PUI Irrigation: NaOCl 5%. pulp stones removal with Ultrasonic tip: BUC One from Spartan. P5 (Dentsply) Sealer used: Pulp Canal Sealer. Obturation technique WVC. X Ray Sensors used: CareStream Kodak 6100. Opmi Proergo microscope. Tooth is ready for crowning.