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ePaper created 2016-03-31, 16:35:38 | version 1.38.0
| technique file separation 20 roots1 2016 Removing separated files with the Terauchi File Retrieval Kit Author: Dr L. Stephen Buchanan, USA I once asked my good friend Dr Yoshi Terauchi how many canals he shaped with a given nickel titanium rotary file before discarding it and bringing a new file intotheprocedure.Heanswered,“Iuserotaryfilesun- til they break, I remove the broken segment and then get a new file.” WHAT? I thought to myself as I looked at him like he had two heads. This blew my mind be- cause, for me, any practice day that includes the oc- currence of “Short File Syndrome” is a really bad day in the life of most any dentist who provides RCT ser- vicestopatients.Iskepticallyaskedhimhowhecould say that with a straight face, and he told me that it only takes him one to five minutes to remove most any separated file from a root canal. So now I have heard two different and apparently ridiculous statements from Yoshi; first, that he does notfearfilebreakage,andsecondly,thatheconsiders theretrievalofbrokenfilestobeapredictableproce- dure requiring relatively little time to accomplish. REALLY? Fortunately, knowing Yoshi for years al- lowed me to suspend disbelief about these outra- geous statements long enough to query him for an explanation. And what he told me turned all of what I supposedly “knew” about file retrieval on its head. These popular myths included: 1. Ultrasonic tips should trough the outside-of-the- curvature canal wall. 2. Ultrasonic tips work best dry when attempting file retrieval. 3. File segments that have been loosened with ultra- sonic vibration are nearly removed. 4. Retrievingbrokenfilesegmentsnecessitatesweak- ening of the tooth. 5. Files segments cannot be removed from the apical third of a curved canal. Here are the critical truths about removing separated files, most of them discovered by DrYoshiTerauchi,andtheTerauchiFileRetrieval Kit (TFRK) he has designed to accomplish this previously challenging procedure (Fig. 1). Troughing the canal wall on the inside of the curve Perhaps the greatest paradigm shift in my thinking on this subject circled around where weshouldworkultrasonictipsnexttothefrac- turedsurfaceofthefilesegment.Itseemslog- ical to trough the canal wall on the outside of its curvature, because that is where the frac- tured edge is engaged. The counter-intuitive truth,asexplainedtomebyYoshi,isthattroughing on the outside of the canal curve doesn’t work be- cause:a)troughingthethatwallincreasesthecurva- tureofthecanal,whilecuttingtheinside-of-the-curve canalwallstraightensthecanal,andb)activatingthe ultrasonictipontheoutside-of-the-curvewallham- mers the file segment and actually moves it further into the canal. When Yoshi first explained this to me, Igotthedumbchills.Troughingontheinsidecurveof a canal requires small ultrasonic tip ends to be bent, without kinking, so they can slide down the inside of the curve, but what a difference it makes to do it this way. YoshihasdesignedtwobeautifulMicro-SpoonTips (Fig. 2) that he uses to cut a trough between the file Fig.1:TheTerauchi File Retrieval Kit. (Photos/Provided by L.Stephen Buchanan,DDS,FICD,FACD) Fig.1