Torsional properties of pathfinding instruments.

INTRODUCTION: This study compared the torsional properties of 2 stainless steel endodontic pathfinding instruments: C-Pilot (VDW, Munich, Germany) and C(+) files (Maillefer/Dentsply, Ballaigues, Switzerland). Stainless steel conventional K-type instruments (KCC(+), VDW) were used as controls. METHODS: File sizes 10 were subjected to a torsional assay in clockwise rotation. The 2 parameters evaluated were maximum torque and angular deflection at failure. The fractured surfaces and the helical shafts of the fractured instruments were then examined by scanning electron microscopy (SEM). RESULTS: The results indicated that the angular deflection to fracture decreased in the following order: KCC(+) > C-Pilot > C(+). As for the maximum torque values, the results revealed the following descending order: C(+) > KCC(+) > C-Pilot. SEM analysis revealed that plastic deformation occurred along the helical shaft of the fractured instruments and that the fractured surfaces were of the ductile type. CONCLUSIONS: The instruments tested showed different torsional behavior depending on the parameter evaluated. Considering that high angular deflection values may serve as a safety factor for instruments used as pathfinders, the conventional K file showed significantly better results than both C-Pilot and C(+) files.