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ePaper created 2016-03-31, 16:35:38 | version 1.38.0
file separation technique | 21roots1 2016 andtheinsideofthecurve.ThetwoMicro-SpoonTips in the TFRK face toward (the 6 o’clock tip) and away from(the12o’clocktip)theultrasonichandpieceand are chosen relative to the direction of the canal cur- vatureandthepositionthehandpiecewillbeinwhile thetipisusedtocutatroughontheinsidecanalcur- vature, adjacent to the file segment. All the ultrasonic tips in the TFRK are made of duc- tile stainless steel and they are extremely elongate, makingthemeasytopre-bendbutsusceptibletopre- mature breakage if not used correctly. The appropri- ate power setting for use of these tips is typically in thelowerquarteroftheultrasonicunit'spowerrange and must be activated intermittently by tapping the foot control rather than in continuous mode. Inter- mittent switching keeps the tips from over-heating and sends a relatively powerful ripple through the long, thin instruments. After two or three pulses, the tips are removed and examined for derangement, theyarecooledandcleanedwithawetalcohol2-by-2 sponge, and are then replaced for further work until thefileisloosened.Workingultrasonictipsnexttofile segmentswithcontinuoususeratherthanpulsedac- tivationalsoincreasestheriskofbreakingthefileseg- ment into smaller pieces. Cutting dry but ejecting file segments wet Dentiststypicallyuseultrasonictipswithoutwater spray so that the tip can be seen as it works, and this ishowtheTFRKtipsshouldbeuseduntilthefileseg- ment has been loosened. However, once the file seg- ment has been loosened, it can be quite difficult to getittocomeoutofthecanalunless17percentEDTA solution is added to the canal and a TFRK Spear tip (Fig.3)isusedinapush-pullmanner,again,between the file segment and the inside-of-the-curve canal wall. TheSpearTipsareextremelythinandsharpattheir tip ends—a necessity for them to further vibrate file segments, yet allow space for the file segment to es- cape between the Spear Tip and the canal diameter at the level of separation. While they are manufac- tured to a fine point, it is recommended by Yoshi that the latch-grip rubber polishing point included in the TFRK be used to further thin and sharpen the Spear Tips before and between uses as they will dull with use, rendering them too large at their ends to allow the file to escape when vibrated. Having never considered removal of a file segment with fluid in the canal, I am still amazed at the differ- ence this makes to the outcome. Most of the time the filesegmentsimplydisappearsfromthecanal,having shotoutathighspeed,sometimeslandingontherub- ber dam outside the tooth. Fig.2: TFRK ultrasonic Micro-SpoonTip. Fig.3:TFRK ultrasonic SpearTip. Fig.4:TFRK Micro-Lasso (Yoshi Loop). Fig.5: Close-up ofYoshi Loop cannula pre-bent for insertion into a canal. Fig.6: Yoshi Loop after retrieving a file fragment. Fig.2 Fig.4 Fig.5 Fig.6 Fig.3