A COMPARISON OF ROOT-CANAL PREPARATIONS USING NI-TI HAND, NI-TI ENGINE-DRIVEN, AND K-FLEX ENDODONTIC INSTRUMENTS

This study used a modified Bramante technique and new digital subtract ion software to compare root canals prepared by nickel-titanium (Ni-Ti ) hand, Ni-Ti engine-driven, and stainless steel hand endodontic instr uments. Sixty mesial canals of extracted human mandibular molars were randomly divided into five groups. The roots were embedded in clear re sin and cross-sectioned in the apical and mid-root areas, In group A, canals were instrumented using a quarter turn/pull technique with K-Fl ex files. In group B, canals were prepared with Ni-Ti hand files (Mity files) using the same technique as in group A. Group C was prepared w ith NT Sensor engine-driven files. Group D canals were prepared with N i-Ti Canal Master ''U'' hand instruments. Group E was prepared with en gine-driven Ni-Ti Lightspeed instruments. Digitized images of the unin strumented canals were compared with images of the instrumented canals . Engine-driven Ni-Ti instruments (Lightspeed and NT Sensor file) and hand instrumentation with the Canal Master ''U'' caused significantly less canal transportation (p < 0.05), remained more centered in the ca nal (p < 0.05), removed less dentin (p < 0.05), and produced rounder c anal preparations than K-Flex and Mity files. Engine instrumentation w ith Lightspeed and NT Sensor file was significantly faster than hand i nstrumentation (p < 0.05).