Which practice helps prevent ledge formation during canal preparation?

• A. Maintaining patency during instrumentation.
• B. Using aggressive straight files.
• C. Skipping patency checks.
• D. Pre-curving instruments without maintaining patency.

Answer: (A)

Maintaining patency during instrumentation keeps the canal open and preserves its original trajectory as you clean and shape it. A ledge forms when the file creates a new artificial path along the wall instead of following the natural canal, often from debris packing or loss of control in a curved canal. By regularly using a small file to pass beyond the working length and by recapitulating with irrigation, you keep the apical area accessible and the file tracing the true canal curvature. This minimizes the chance of the instrument riding on one wall and creating a ledge. The other practices described would raise the risk by encouraging debris blockage, transportation, or false pathways rather than maintaining the canal’s natural path.