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meetings _ AAE 2010 I Perhaps the most time-consuming part of the demonstration was the placement of a screw-fixated retractionfencehedesigned,butoncethetwo1.5mm bone screws had been set, retraction of the mucosa overlying the drill path required no more effort on Buchanan’s part. He noted that inefficient tissue retraction is prob- ably the largest barrier to shortening surgical times dramatically,andthisaspectofGESisobviouslyawork in progress. Despite the challenge of placing the retraction fence and dealing with significant bleeding (the pa- tient had high blood pressure), drilling through the guide, to length, with the 2, 3, 4 and 5 mm drills was very straightforward. After the drill guide had been removed, Buchanan captured a micro-mirror view through the resulting 5mm drill hole—showing the MB root cut perfectly with the previously treated MB1 canal bisected and beyondit,towardthepalatalaspect,adarkenedisth- musthatleddirectlytothepreviouslyuntreatedMB2 canal. He then negotiated and enlarged the MB2 canal through the resected root-end using 0.04 tapered ro- taryNiTifilesinsizes#15/40.Hesaidthe0.04taperlim- itation reduced the accumulation of cyclic fatigue caused by the flexure of the files past the cut root sur- face, allowing him to cut a larger diameter of prepara- tiontothecoronalextentofthecanalthanwouldhave beenpossiblewithinstrumentsthatweremoretapered. Filling this canal created some additional chal- lenges.However,DrBuchananwasabletoaccomplish thiswithapressuresyringeloadedwithpinkCavitand a27-gaugeneedle,resultinginadensefillalltheway tothepulpchamber.DrBuchanantypicallyusesCavit because: a) it sets in the presence of moisture; b) it seals against leakage as well as MTA does; and c) its viscosityallowsittobesyringedquiteadistancefrom the end of the needle. An alternative with which he has been experi- menting is filling apically instrumented canals with a carrier-basedobturator.Whileearlyresultslookgood (excellentfillsandmuchlesstimeandfrustration),he chosetodothemorefamiliartechnique—perhapsfor the last time. Dental microscopes from Carl Zeiss combine brilliant optical quality with outstanding ease of use in a uniquely designed product. This enables you not only to see the minute details of even the finest structures, but also to work comfortably in a relaxed, upright position during treatment. This optimally protects you against neck strain, back pain and spine disorders. Find out more at: www.meditec.zeiss.com/dentistry Stand out above the rest! Carl Zeiss Surgical GmbH A Carl Zeiss Meditec Company Carl-Zeiss-Strasse 22 73447 Oberkochen Germany Fax: +49 (0) 73 64/20-48 23 surgical@meditec.zeiss.com www.meditec.zeiss.com/dentistry www.meditec.zeiss.com/contacts AD