The Ten Second Rule

This case demonstrates when to stop using ultrasonics and use a Yoshi Loop to retreive a separated file shorter than 4.5 mm. I have a 10 second rule when attempting to remove a separated file using ultrasonics; if an ultrasonic removal attempt exceeds 10 seconds, I usually get out of the canal and proceed with the Yoshi Loop to take it out. The sagittal view of CBCT shows that the separated file is 3.8 mm, which indicated that it could be removed with ultrasonics alone. My treatment plan was that if the separated file removal attempt with ultrasonics failed within 10 seconds after the separated file was seen dancing under the DOM, the Yoshi Loop would be immediately introduced into the canal to retrieve it. The separated file was beyond the curve of MB and dentin sacrifice for instrument retrieval would have been significant if the ultrasonic activation continued more than 10 seconds. Thus, the Yoshi Loop was put in the canal immediately and the separated file was successfully removed in 10 seconds. The radiograph shows that dentin sacrifice was not perceivable compared to the MB canal in the pre-op radiograph.


Doctor Follow Up Questions

Dr. Terauchi, amazing as always. What bur do you use to sharpen the tip? What’s the power setting you recommend for the spoon?

Yoshi Terauchi

Thank you. I use a metal polishing bur. The power setting for ultrasonics is from 1 to 3 on a scale of 1 to 20.