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TECHNIQUES AND METHODS OF PREPARATION OF ROOT CANALS. MDDr . Radovan Žižka. AIM OF SEMINARY. Aim of endodontic treatment Shaping and cleaning Schilder (1974) Contemporary aproach Concepts which are used during root canal preparation Techniques and methods of preparation of root canals.
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TECHNIQUES AND METHODS OF PREPARATION OF ROOT CANALS MDDr. Radovan Žižka
AIM OF SEMINARY • Aimofendodontictreatment • Shapingandcleaning • Schilder (1974) • Contemporaryaproach • Conceptswhich are usedduringrootcanalpreparation • Techniques and methodsofpreparationofrootcanals
AIM OF ENDODONTIC TREATMENT • Aimofendodontictreatmentisdesinfictionofrootcanal, whichisfollowed by hermeticobturation
SHAPING AND CLEANING • Shaping –thepurposeis to prepare a shapeofrootcanalwhichrespectsoriginal anatomy and makespossiblethoroughtcleaning and hermeticobturation • Cleaning – thepurposeis to removeallthematerial in rootcanal (pulp, preparationdebris, microorganisms)
SHAPING AND CLEANING(Schilder,1974) • Shaping • Mechanicalaims • Biologicalaims • Cleaning • Exstirpation • Dissolvingmaterialofbiologicalorigin • Removingpreparationdebris
SHAPING AND CLEANING(contemporaryaproach) • Kompletní přístup • Direct view on thewhole pulp chamberfloor and itsmorphology (rootcanalorifices) • Straight line access • Continuouslynarrowingpreparation • Allowsirrigation and removingofdebris • Allowshermeticobturation
SHAPING AND CLEANING(contemporaryaproach) • Respectingoriginal anatomy • Shapeofrootcanalpreparationrespects and followoriginal anatomy • Protectinghealthyteethstructures • Increaseresistanceagainstfracture • Decrease probability ofperforation • Apicalpreparationshouldbe as small as itispossible to procedeadequatecleaning
CONCEPTS USED DURING PREPARATION • Straight line access (SLA) • Coronalflaring • Workinglenght (WL) • Apicalwidth(AW) • Patency • Recapitulation • Glidepath
STRAIGHT LINE ACCESS • Ideallyshouldworking instrument reachforamenfysiologicum (orfirstcurvature) withoutbending. • Influenced by: • Shapeofaccesscavity • Coronalflaring
CORONAL FLARING • Beforewereachworkinglenghtwithours instrument weshouldprocedecoronalflaring • Removethe most infectedtissue in rootcanal • Createreservoirforirigationsollution • Allowsstraight line access
CORONAL FLARING • Gates-Glidden • Rotatoryendodonticfiles • ProTaper SX • ProFileorificeshapers Zdroje: http://www.dentalcapitalbh.com.br/media/endodontia-maillefer/PROFILE-ORIFICE-SHAPER.jpg http://t2.gstatic.com/images?q=tbn:ANd9GcRFzd64ffFlSVlBgqLeRkas-DSIzpjvIoBZFrX5AWN41mk1WcewZw http://t2.gstatic.com/images?q=tbn:ANd9GcQ1pep7_AoQOTj-39l2cmMbqLtdv-GFWtwTb8lpgIgPjW0YnYD4
WORKING LENGHT • Lenghtofworking instrument from reference point to foramenfysiologicum (boundarybetween cement and dentin) Foramenfysiologicum Dentin Cement Pulp tissue
WORKING LENGHT • Wecanfinditout • Averagevalues – very unprecise. Canbeusedonly as safelenght • Radiologically – unprecise. Fysiologicalforamenisusuallyabout 1-1,5 mm fromanatomical apex • Electronically– electronic apex locator (EAL) are based on pricipalthatresistancebetween oral mucosa and periodontalligamentsisconstant
APICAL WIDTH • Depends on originaldiameter and shapeofrootcanal, usedtaperofinstrume and diagnosis • Hightaper • Lessinfectedrootcanals • Smalldiameter(incisors, calcification) • Unpleasantrootcanal anatomy • Lowtaper • Badlyinfectedrootcanal • Rootcanalretreatment • Biggerdiameter(young patiens, palatalrootof M1)
PATENCY • Keepingapicalforamen free ofdebris by usingpatencyfile (usually K-filesize #10 or#15) thatispassivelyextended just throughapicalforamen • Helps to maintainworkinglenght • Helps to removingpreparationdebris Foramenfysiologicum Patency file Foramen apicale
RECAPITULATION • Checkingtheworkinglenghtwiththeworkinginstrumentswith a 1ISO smallerdiameterthanworking instrument wehaveusedbefore • Helps to maintainworkinglenght • Helps to removepreparationdebris
GLIDEPATH • Usingof (usually) stainlesssteelfilesbefore Ni-Ti rotaroryfiles • Producingsmoothreproducibleglidepathforrotatoryinstruments • Preparationat least to ISO 15(allowsremovingpreparationdebris) • Checkingstraight line access • Valuableinformationabourootcanal anatomy
TECHNIQUES AND METHODS OF ROOT CANAL PREPARATION • Technique – instrumentationwithonefile • Method – instrumentationsequence (canobtain more techniques) • Wedivide to hand, rotatory,hybrid (following are hand ones)
TECHNIQUES OF ROOT CANAL PREPARATION • Standarized (watch-winding) • Reaming • Filing • Balancedforce
STANDARDIZED TECHNIQUE • Indication • Initialprobingofrootcanal • Recapitulation • Retreatment • Complication • Extrusionofpreparationdebrisbeyond apex • Ledge • Instruments • K-reamer, K-file
STANDARDIZED TECHNIQUE Instrument ispushingapicallyduringrotating in clock-wise and anti clock-wisedirection (about 45°) 15 15
REAMING TECHNIQUE • Indication • Straightrootcanalsofcirculardiameter • Complication • Straighteningofrootcanals • Zip-elbow • Instruments • K-reamer (rotation 45°) • K-file (rotationlessthan 45°)
REAMING TECHNIQUE Wepass instrument passivellyto rootcanal and thenwerotateitaround 45° withsmallpresure.Thenwetakethe instrument out. 15
FILING TECHNIQUE • Indication • Oval shaperootcanals • Retreatment • Smoothingthepreparation • Complication • Extrudingdebristhrough apex • Instrument • H-file
FILING TECHNQUE We insert instrument passivelly and thenpullit up 2-3mm againsrootcanalwall. It´sneccesary to irigate very often and equalpreparationofwalls. 15
BALANCED FORCE TECHNIQUE • Indication • Complicatedrootcanal anatomy • The most universal techniqueforglidepath • Complication • Straighteningofrootcanal • Instrument • K-flexofile (Flex-R file) • K-file
BALANCED FORCE TECHNIQUESTEP 1 Insert instrument passivelywhich has 1ISO diameterlargerthancurrent master apicalfile. 15
BALANCED FORCE TECHNIQUESTEP 2 Withsmallpressurewerotate instrument around 90° in theclock-wisedirection. Instrument willengage dentin oftherootcanalwall. 15
BALANCED FORCE TECHNIQUESTEP 3 Withminimalpressurewerotate instrument around 180-270° counterclockwisedirection. Pressureshouldmaintain instrument atorneartheclockwiseinsertiondepth. Itwillbreakloosetheengaged dentin chipsfromrootcanalwall. 15
BALANCED FORCE TECHNIQUESTEP 4 Thefile si thenremovedfromrootcanal by a slowclockwiserotationaround 360° thatloadsdebrisintotheflutes and elevatesisaway. 15
BALANCED FORCE TECHNIQUESTEP 4 Becausewedon´t use prebend filesthestraighteningofrootcanalcanoccur. Ifrootcanaliscomplicatedwesuggestinsteadof step 4 go on with step 1 untiltheworkinglenghtisreached. (ledge and breakage are more probable)
METHODS OF ROOT CANAL PREPARATION • Apicocoronal – wepreparafrombeggingwithcompleteworkinglenghtorweshortenit. • Combined (reaming-filing) • Step-back • Coronoapical – wepreparewithshortenedworkinglenghtwhichisfurtherprolonged. • Step-down • Double flared • Crowndownpresureless
COMBINED METHOD • Indication • Straightcanals (oval) • Recreationofapical stop afteroverinstrumentationof apex • Complication • Zip-elbow, perforation (in case ofcurvature in apical part ofrootcanal) • Instruments • Changingof K-file and H-file
COMBINED METHOD By K-filewepreparewithbalancedforcetechnique up to workinglenght Thenpassively insert H-file and withfilingtechniquewepreparerootcanal Werepeatwholeprocedurewithfiles 1 ISO larger. 15 20 15 20
STEP-BACK METHOD • Indication • Mediate to severe curvedcanals • Complication • Reductionoftheiroccurence • Timedemanding • Instruments • In the past prebend H-file, these days are prefered K-files
STEP-BACK METHOD • Main idea iscontinuousshorteningtheworkinglenghtofinstrumentswithlargerdiameter • Itconsistsoftwosteps • Preparationofapical stop • Preparationofcontinuouslywideningtaper
STEP-BACK METHOD • Preparationoftheapical stop which has adequatediameteratthecorrectworkinglenght (forexample ISO 35) • Next instrument isinsterted to shortenedworkinglenght (originalworkinglenght – 0,5 mm) and preparationisrepeated • In the end wepreparewith master apicalfile to make rootcanalwallssmooth 35 40 45 50 55 60
STEP-DOWN METHOD • Indication • Formerlyinventedformolards • Mildlycurved, rather oval rootcanals • Complication • Reductionofoccurence • Timedemanding • Instruments • Combinationof K-file, H-file, Gates-Glidden
STEP-DOWN METHOD • Contains 3 steps • Aimis to: • Determineworkinglenghtwhichisconstant • Minimalizethepossiblityofextrusionthedebristhrought apex • Preciserecognitionofapicalwidth
STEP-DOWN METHOD 1.Step Preparationofcoronal 2/3 ofrootcanalwithfilingtechnique (H-files ISO15,20,25), workinglenghtcanbedeterminedwith ISO 8 instrument. 2/3 15 20 25
STEP-DOWN METHOD 2.Step CoronalflaringwithGates-Glidden (1-4), orProTaper/ProFile 2/3
STEP-DOWN METHOD 3.Step Preparation to workinglenght (min. ISO 35) withbalancedforcetechnique and followed by step-backtechnique
DOUBLE FLARED METHOD • Indication • Almost no restriction • Complication • Reductionofoccurence • Instruments • K-file, Gates-Glidden
DOUBLE FLARED METHOD In factit´s step-downmethodwherethefirst step ismissing. Thoroughtcoronalflaringbringssameadvantages as with step-downmethod. In thesametimeisreducedpossibilityofextrudinginfectionapically Koronalflaring + step-back
DOUBLE FLARED METHOD 1.Step CoronalflaringwithGates-Glidden (1-4), či ProTaper/ProFile 2/3
DOUBLE FLARED METHOD 2.Step Preparation to workinglenght(min. ISO 35) by balancedforcetechnique and followed by step-backmethod
CROWNDOWN PRESURELESS METHOD • Indication • Curvedrootcanalsofrounddiameter • Excellentshapeofpreparation • Complication • Same occurence as with step-back and double flaredmethods • Instruments • K-file
METODA CROWNDOWN PRESURELESS • Workingwith no pressure • Determiningworkinglenght (Forexample ISO 15) • Firstlywe use instrumentsoflargerdiameters and rotatecounterclockwisedirection (wedo not insert them to full workinglenght) (Forexamplefrom ISO 50) 15 50 45 40 35 30 25 20
CROWNDOWN PRESURELESS METHOD Thenwewouldrepeatwholesequence, thistimewithfilesof 1ISO largerdiameter (Forexamplenowfrom ISO 55),so many to times, to obtainapicalwidthwhichisdesired Thismethodisused by the most ofrotatoryendodonticsystems