March 31, 2012
No one bit re; an answer to how to remove the separated instrument from a blog entry a few entries back………..thus, not to leave ya hangin’……..
Comment from dentist performing the procedure asking for assistance: “The tooth was necrotic, the referring dentist said he got to the apex with a #20 K file and then separated a 25/06 Twisted File in the MB canal. He also added that there is straight line access so I should be able to get it out.” – the question you must be asking is why then did the file separate. Twisted Files are not “ground” – they are supposed to unwind under torque – ask yourself why a NiTi rotary would separate; incomplete guide path, inaccurate length determination, straight line access wasn’t straight, no lubricant or irrigant, more than a single usage, thread rate too fast, anon……….
Removal: Create a stage, all the world loves a stage: Flatten a Gates Glidden bur (usually a size 2 or 3) to create a platform just below the maximum “bulge width” of the bur and drill down to the separated instrument with care and constant irrigation. Next use a very thin narrow ultrasonic tip to “chip” the platform of dentin away from the separated instrument. Be sure to do it without water and clear away all the debris away with EDTA or Citric Acid. What this does is creates space alongside the loosened file allowing you to pass a small .06 or .08 file by it. Once you’ve made this happen you’re home free. Flood the canal with RC Prep which keeps all debris in loose suspension so the gap you’ve created won’t clog up with debris. The alternative to a very small tip is to use a SONOFILE and click the tip and refine it……see photo………
Once you’ve bypassed and recapitulated a few times and the instrument is loosened it will float out at some point. If you are meticulous and not heavy-handed, you can carefully slip a 15 Hedstrom alongside the separated instrument, then give it a quick flick and pop it out as it engages the flutes. Or slip two and braid them to assist in removal. The key is to completely bypass the separated instrument and establish patency if you can. This will allow very thorough irrigant flushing and clearing of debris around the instrument facilitating its removal. If you try to cram a Hedstrom in too soon and become impatient, you are likely to separate the Hedstrom or shred the file making its removal and the second SI you created even more difficult to remove. Choose your tips carefully….you can use the EIE Slim Jim tip (UT4) or the altered SONOFILE – avoid the coated ProUltra tips, use the smaller coloured tips the 6, 7, 8. The key is to use the #2 Gates if possible and avoid deep bulge mid-root in the danger zone of the canal. I’ve seen articles on instrument removal that include comments such as the small extra-radicular perforation caused was sealed with MTA…….duh? The other alternative to retrieval is the Ruddle iRS system. It’s a good instrument but, it’s use is dependent on visualizing the instrument completely which is not always possible in mesial canals without significant structural removal. It’s difficult to visualize around the cannula and as you can’t see it engage, it has to be done by touch, more complicated for files, but very effective for Ag cones……
In the file below, there is reference image for acoustic streaming which is the sine qua non of all irrigation techniques…..all the new file metals, design, single file usage only alludes to the TRUE POWER OF IRRIGATION in passing…..it’s not because of importance and relevance, it’s because of the economic realities, files cost more than irrigation disposables…..and there for an eternity has lain the inherent problem in iatrogenic endodontic situations.