An In vitro comparative evaluation of a hand file and three rotary Nill Instruments for removing gutta percha during root canal re-treatmen
Objective: To evaluate the efficacy of NITI mechanical rotary instrumentation and Hedstrom file for gutta percha removal using dearing technique.Method: Forty extracted human single rooted premolar, each with a single canal were selected.The samples were decoronated to leave 17 mm root and Instrumented with K-flles upto MAF 30 using step back techn