Micro-Trephine Bur (TFRK-MT) Frees Stubborn Files
The Micro-Trephine Bur (TFRK-MT) from the TFRK is used to loosen file segments deeply engaged in the canal wall. This case illustrates the successful removal of a file segment shorter than 4.5 mm with the Yoshi Loop.
The file did not dance with ultrasonics after a thin space was created using the ultrasonic tip, about one-third of the file segment’s length. The clinician loosened the broken file with the TFRK-MT, and applied the ultrasonics again, successfully causing the file to dance. The 10 second rule was applied to this case- if a separated file doesn’t come out in 10 seconds with ultrasonics alone, make sure that the ultrasonic tip used for instrument retrieval was thin enough to let the file exit, and that no overhang exists from the outer wall. If the file remains stuck, switch to the Yoshi Loop instead of continuing to activate ultrasonics.
This rule of thumb prevents dentin sacrifice and preserves the healthy dentin. The separated file measured 3.5 mm on the sagittal and coronal view of CBCT and was verified after retrieval as the same. The instrument retrieval procedure took about 6 minutes.