Summary:
Purpose: to describe the balanced force technique to support its validity, and to make its concepts available so that
others may also examine and test its validity.
Rational :
- K-files are bidirectional cutting tools, allow the clinician to select any of the four potential cutting approaches (insertion, withdrawal, clockwise, or CCW)
- Restoring force: applied against the curvature by the file to return to its original straight condition.
- Restoring force will increase if:
1.Metal mass increase (trianglular vs. square)
2.Radius of curvature decrease
3.Arc of the canal curvature increases
4.Distance from the curve to the file tip is decreased
- Extending file beyond apex before next larger file (undesirable)
- Modification of the file tip
Technique:
- Clockwise rotation up to 180 degrees, counterclockwise rotation at least 120 degrees with apical pressure.
- Until the WL is reached. Then a larger size instrument is used in the same manner.
- Final clockwise cleaning rotation is used to load canal debris into the flutes.
- If file was over extended, enlarge the apical size by 2 large files to the WL to create apical stop.
