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ePaper created 2016-11-22, 09:52:12 | version 1.38.0
| technique access cavities 24 roots 4 2016 So it is with endodontics. When we realize how criticalthequalityofouraccesspreparationsistothe remainder of the case, it feels like fingernails on a chalkboard to head into a canal before securing an ideal path into it. Aristotle got it right—excellence is ahabit,notacharactertrait.Sowhatdothehabitsof access excellence look like in this 21st century? Failing to plan is planning to fail Atul Gawande, in his book “The Checklist Mani- festo,”2 describes the importance of planning not just which procedure to do, but how every single aspect of thatproceduremustbeplannedindetail,fromstartto finish,ifconsistentlyidealresultsarethegoal.Doesthe preoperativeimagingaccuratelydescribetheanatom- icalchallenges?Doestheclinicianhaveadequatemag- nificationandlight?Arethecuttingtoolsadequateand well chosen? Are the locations, angles and depths of entry determined before beginning the procedure? Havemaximalsafecuttinglengthsbeenmarkedonac- cess burs? Are there procedures in place to deal with calcifiedcanalsthatdefylocation?Andsoon. In other words, the Alfred E. Neumann attitude of “What, me worry?” is not appropriate during this critical event. Conversely, when each of these critical elements is included in the treatment planning and execution of an ideal access cavity preparation, the rest of the procedure becomes progressively simpler as the finish is approached. Radiographic imaging Wewouldn’tevenattemptRCTwithoutRoentgen’s invention of the dental radiograph, so it is not much ofastretchtoclaimthecriticalnecessityofidealpre- operative radiography. Ideal preoperative X-ray im- agingmustincludeastraight-onanglethatsplitsthe mesial and distal contacts perfectly—taken either as aperiapicalorasabitewingX-rayimage,thenatleast oneidealoff-angleviewinordertocapturedatafrom the Z-plane (buccolingual) of the tooth in question. In my practice, a mesial off-angle view of anteriors andpremolarsworkswell,becauseitismucheasierto capture than a distal angle, and in anteriors and pre- molarsthemesialviewrevealsasmuchradicularanat- omyasadistalview.Inmolarsitisdifferent.Inmolars adistalviewisfarpreferabletoamesialoff-angleview, as the mesial view superimposes the body of the root overthedistallycurvedrootstructure,whilethedistal view casts the apical root end sideways, where it can be more easily seen on the radiographic image. Of course, cone-beam CT (CBCT) imaging is the unfair endodontic imaging advantage. If told I could have either a microscope or a CT machine, but not both, I would choose 3-D imaging every time. Only CBCT imaging can capture the mesial view of root structure—the view in which we see “The Secret Life of Root Canals”—the bucco-lingual plane containing the greatest degree of anatomic complexity. One of thegreatestjoysofhavingaCTmachineinpracticeis knowing, for sure, before the access procedure is be- gun,thatthereisonlyasinglecanalinthemesiobuc- cal root of an upper molar. Conversely, one of the few negative experiences to be had with this technology iswhenthereconstructedvolumeshowstwoorthree canals, in a root that has given up only one to the cli- nician’s exhaustive search. Fig.5: Postoperative radiograph of a mandibular molar treated through the mesial carious defect and a second small entry cut through the central fossa.Preserving dentin between entry points is referred to as a‘truss’ access configuration.(Photo:Provided by Dr John Khademi) Fig.6:This postoperative radiograph shows a very diminutive access cavity opening with both mesial and distal lateral pulp horns left intact during the RCT procedure and filled during the postendodontic restorative effort.This appearance is a matter of pride among those in the‘IBAC’ club. (Photo:Provided by Dr Jeff Pafford) Fig.7: Mandibular molar with nearly total calcification of the pulp chamber prior to RCT,accomplished through two perfectly dead-on access entry ports,leaving a 0.75 mm high pulp chamber isthmus between.Note the definitive treatment results in the apical thirds of each canal. (Photo:Provided by Dr N.Pushpak) Figs.4a & b:Access cavities cut in a crown-prepped molar requiring RCT (left).Postoperative radiograph (right) showing beautiful management of root canal shaping,cleaning and filling — despite the minimal size of entry. Note the largely remaining pulp chamber roof.(Photos:Provided by Dr Steve Baerg) Fig.4a Fig.4b Fig.5 Fig.6 Fig.7 42016