When attempting to remove a separated instrument with ultrasonic techniques, what is the best approach?

The recommended approach when removing a separated instrument using ultrasonic techniques is to block or obturate the non-involved canals first. This strategy is crucial because it helps to prevent any potential cross-contamination between canals during the removal procedure. By sealing the non-involved canals, you create an isolated environment that mitigates the risk of debris or irrigants from the affected canal interfering with the healing of the other canals.

Additionally, this approach provides better access and visibility, allowing for a more controlled environment when applying ultrasonic techniques to retrieve the separated instrument. It also helps maintain the integrity of the overall treatment since any inadvertent access or complication in one canal can jeopardize the success of the entire endodontic procedure.

In contrast, attempting to remove the instrument without first blocking the other canals could lead to difficulties in accessing the fragmented piece, and using heating techniques or other obturation methods in this situation could complicate or compromise the treatment further.