Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-03-31, 16:35:38 | version 1.38.0
| technique file separation 22 roots1 2016 File length as a predictor of retrieval The third critical issue influencing file retrieval that Dr Terauchi has figured out is that the length of the file segment is actually more important than its position in the canal. He has determined, through experimentationdoneinextractedteethandproven in patient’s teeth, that the length of the broken file segmentinfluencesthedifficultyofitsremoval;that file segments greater in length than 4.3 mm will of- ten require more than Micro-Spoons and Spear- shaped ultrasonic tips to eject them from the canal. Early in the development of his technique, after DrTerauchirealisedtheimportanceoffilesegment length,hewouldintentionallybreakseparatedfiles longer than 4.3 mm by using higher power settings and more continuous activation of an ultrasonic tip. Unfortunately, this caused more frequent breakage of ultrasonic tips and required another troughtobecutfurtherintothecanaltoloosenand remove the remaining, most apical portion of the separated file after the more coronal segment had been removed. It was the search of a better solution to this co- nundrum that inspired him to invent what I call the Yoshi Loop (Figs. 4–6), a stainless steel micro-lasso that extends from the end of a stainless steel can- nula attached to a handle with a retraction button for tightening the Loop around a loosened file seg- ment.Liketheultrasonictips,theYoshiLoopissmall fragile,andeasilybrokenwhenmisused,butalarger tool will never retrieve a file segment from a canal. Also,itmustbecarefullypreparedbeforeattempt- ingtoencircleapreviouslyloosenedfilesegment.The redretractionbuttonismovedforwardtoextendthe wire lasso, a DG-16 explorer tip is placed inside the lasso, and the retraction button is then carefully pulledbackwarduntiltheloopisfelttotightenonthe explorer tine, thus rounding the loop so that it may be placed around the end of the file segment. Before removing the explorer from the Loop, it is rotated back to a position parallel to the cannula to bend the rounded Loop to a 45-degree angle. This rounded, angled Loop wire is then ideally formed to drop aroundtheendofthefilesegmentasitismovedinto position (Figs. 7a–d). Fig.7a: DG-16 explorer tip placed into wire loop. Fig.7b: Wire loop is tightened and rounded on the explorer tine. Fig.7c: Explorer is rotated to be parallel to loop cannula. Fig.7d: Loop rounded and angled, ready to capture a file segment that has been loosened but will not come out of the canal. Fig.7a Fig.7c Fig.7b Fig.7d