This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
Background: The aim of this study was to evaluate and compare the effectiveness of manual files and rotary nickel–
titanium instruments operating in continuous rotation, reciprocation, and optimum torque reverse (OTR) motion for
correction of ledge formation in simulated curved root canals.
Materials and Methods: Eighty standardized acrylic blocks with curved canals were used. Ledges were artificially
created at a standardized level. Specimens were randomly divided into four groups (n = 20): manual stainless-steel
files, continuous rotary NiTi, reciprocating NiTi, and OTR NiTi systems. Ledge correction was attempted using
standardized protocols. Outcomes included success rate of ledge correction, time required to regain working length,
and change in canal curvature. The significance level was set at P ≤ 0.05. Statistical analysis was performed with
IBM® SPSS® Statistics Version 25 for Windows.
Results: Manual files demonstrated the highest success rate in bypassing ledges, while reciprocating and OTR
systems showed significantly reduced correction time. Continuous rotary instruments exhibited greater change in canal curvature compared with other groups.
Conclusion: Manual files remain the most reliable instruments for initial ledge bypassing, whereas rotary systems
particularly those using OTR and reciprocation can efficiently refine canal shaping after correction. Instrument
kinematics significantly influence ledge management outcomes.