Aliquota IVA applicata: 22%
Step 1. Expanding the canal to the broken file and flaring the canal.
Use the Gates No. 3 reamer to expand the canal to the broken file and brush against the outer wall to widen the canal when the canal curvature is less than 15 degrees.
Use a NiTi conical file size 60/.02 to enlarge the canal up to the broken file and brush against the outer wall to enlarge the canal when the canal curvature is greater than 15 degrees.
Step 2. Create a 90-degree semicircular space.
Use ED88 (Katana-H) and ED89 (Katana-V) to create a thin space between the inner wall and the fracture. Direct the ↓surface↔a from the tip to the broken file from the inner wall and activate the ultrasound by positioning it in the gap. The depth of the space must be at least one.
one-third of the length of the broken file. When the angle is greater than 30 degrees, a drop of medical-grade silicone oil is inserted into the canal to facilitate lubrication and loosening of the broken file. The depth of the void under these conditions should be at least half the length of the broken file.
Step 3. Extend the peripheral space from 90 degrees to 180 degrees.
Use ED87 (TFRK-S) to extend the semicircular space from 90 degrees to 180 degrees until the broken file is seen "dancing" (moving from the original space to another) under magnification. In clinical practice, the tip is used with beaking and pulsating movements to avoid incidents. Do not press the tip against the canal and activate ultrasound because the tip will break due to cyclic fatigue.
To widen the space laterally, the tip should be used with an up/down motion to cut the dentin, not laterally.
Step 4. Once the preparation is complete, use the ultrasonic tip used when the broken file was "played" for ultrasonic extraction attempts. First, the canal is filled with 17% EDTA when the canal curvature is 30 degrees or less, or with vegetable oil such as soybean oil when the canal curvature is greater than 30 degrees.
Position the ultrasound tip in the space created in the inner wall and activate the ultrasound in a short vertical movement inside the prepared space until you see it come out of the channel.