ROEN0310

08 I I clinical report _ continuous wave technique _Step 3a: Syringe-backfill technique The speed of extrusion is set on the control panel of the System-B/Elements unit. After pre-heating is completed(45seconds),theforwardtoggleswitchon the handpiece is pressed until material extrudes out of the needle tip to ‘prime’ the needle. The heated needlecanthenbeplacedintothecanalfor5seconds, allowing the needle to reheat after being cooled by contact with the dentine. After the 5-second pause, with the needle lightly held in place, one of the handpiece toggle switches (back button for medium speed, forward button for faster speed) should be activated in order to extrude the gutta-percha. After the extruded material has filled the backfill space ahead of the needle, the back-pressure of the extruded gutta-percha will movetheneedlebackoutofthecanal.Atthispoint,it isimportantthattheclinicianresistthetemptationto pull the needle out of the canal. The extruded gutta- percha should be allowed to back it out. Care should be taken to allow approximately 5 to 10 seconds for the needle to reach the orifice level. Using the rigid, stainless-steel end of the appro- priate CW hand plugger, a very firm condensation push should be given to the warm gutta-percha. A void of 4mm can be filled if sufficient pressure is applied. _Step 3b: Single-cone backfill option (ideal for medium and large canals) While the filler material should be down-packed through the master cone as usual, the 1-second separationburstisnotnecessary.Instead,theplugger should be allowed to cool in the canal for approxi- mately 10 seconds (two clicks from the unit). The plugger can be removed by rotating it back and forth withapicalpressure,andthestill-coldpluggercanbe teased out during rotation. An AutoFit backfill cone (the same size as the plugger used for the down-pack) can be coated with sealer,andmovedinandoutoftheemptyback-filling space three to four times in order to ensure that the sealer material coats the backfill space. The area left by the plugger will exactly match the shape of the backfill cone. The cone can then be seared off at the orifice level with the System-B/Elements electric heat plugger. The rigid, stainless-steel end of the hand plugger can then be placed against the gutta-percha. With a firm sustained pressure, the coronal mass can be condensed at the orifice level. This technique is ideal for filling voids created during an extruder backfill. The stop on the CW electric heat plugger should be adjustedsothatitwillreachbeyondtheexistingvoid. The heated plugger can then be thrust through the void, cooled for ten seconds, then removed so that the backfill can be completed following the steps outlined above._ roots3_2010 Dr L.Stephen Buchanan is a Diplomate of theAmeri- can Board of Endodontics and a Fellow of both the International Collegeof DentistsandAmerican CollegeofDentists.Clinicians interested in his DVD series, TheArt of Endodontics,and hishands-onlaboratoryworkshopsinSantaBarbara, USA,cancall+18005281590(USandCanada)or +18058994529(forinternationalcalls). For more information related to this article and for GTX updates and answers to frequently asked questions,please visit www.endobuchanan.com. Free CE online courses are also available on the GTX System and other topics. _about the author roots Fig. 12 Fig. 13 Fig. 14 Fig. 15