A comparison of the shaping abilities of 4 nickel-titanium rotary instruments in simulated root canals

Objective. The purpose of this study was to compare the root canal shaping abilities of 4 nickel-titanium rotary instruments. Study design. ProFile, GT Rotary, Quantec, and ProTaper files were used to instrument 48 simulated curved root canals in plastic blocks with the crown-down technique. One operator prepared all the canals until reaching an apical canal size of #30. The instrumentation time, changes of canal dimension and curvature, canal aberration, and instrument deformation were evaluated. Data were analyzed by using one-way analysis of variance followed by the Duncan multiple range test. Results. The ProTaper took significantly less instrumentation time, removed more canal wall (especially at the inner side of the canal curve), lessened the canal curvature, and induced more instrument deformation than did the other instruments. Conclusion. Although ProTaper files cut more canal wall more quickly than the other instruments in the curved canal, they were also the instruments that most frequently became deformed.