ObjectiveObjectivess
•Achieve maximum visibility of the canal
•Determine precise root canal location
•Allow for proper cleaning & shapingof the canal
•Remove causes of bacterial infection
EndodonticEndodontic CavityCavity PreparationPreparation
Coronal cavity prep
“Access Opening”
RadicularCavity Prep
“Root Canal Preparation”
PrinciplesPrinciples of Access Openingof Access Opening
Removal of carious dentine & defective restorationsOutline formConvenience formToilet of the cavity
RemovalRemoval ofof remainingremaining cariouscarious dentindentine & e & defectivedefective restorationsrestorations
Point to start openingaccessEliminate thediscolored toothstructure
RemovalRemoval ofof remainingremaining cariouscarious dentindentine & e & defectivedefective restorationsrestorations
Eliminate as manymicro-organisms aspossibleEliminate thepossibility of salivaleaking into theprepared cavity
Failure to remove caries or faulty Failure to remove caries or faulty restorationsrestorations
Reasons to remove restorationsReasons to remove restorationsEvidence of leakageEvidence of leakageCaries beneath restorationsCaries beneath restorationsFracture uncovered during access Fracture uncovered during access preparationpreparationTxTx--planned restoration replacementplanned restoration replacementConvenience to workConvenience to work
ShapeShape ofof AccessAccess OOpeningpening
MaxMax insicorinsicorMaxMax molarmolarMandMand molarmolar
ShapeShape ofof AccessAccess OpeningOpening
MandMand incisorincisorMaxMax && mandmand caninecanineMaxMax && mandmand premolarpremolar
OutlineOutline formform
Evolves from internal anatomy- Age of tooth- Number, position & curvature ofcanals
ConvenienceConvenience formformUnobstructed access to the canalorificeDirect access to the apicalforamen
ConvenienceConvenience formform
Expansion to accommodatefilling techniquesComplete authority overthe instruments
ledge
Inadequate convenience form Inadequate convenience form leadleadss toto::
1.ledging
2.instrument breakage
3.incorrect shape of complete canal
4.improper debridement
ToiletToilet ofof cavitycavity
Remove aRemove allll cariecaries & s & debridebrissfromfrom chamberchamber beforebeforeradicularradicular prepprep isis begunbegunEndoEndo spoonspoon excavatorexcavator isis idealidealforfor debrisdebris removalremovalNaOCNaOCll isis an an excellentexcellentirrigationirrigation
Access Access ที่ดีมีลักษณะที่ดีมีลักษณะ
1.No caries or defected restoration
2.No roof of pulp chamber
3.Straight line access
Access Access ที่ดีมีลักษณะที่ดีมีลักษณะ
4.ผนังเรียบตอเปนเสน
เดียวกับผนังคลองรากฟน
5.มลีกัษณะเปนรูปกรวย
ผายออกเลก็นอย
6.ไมกรอเนื้อฟนมาก
เกินไป
การเตรียมฟนกอนการเปดชองทางเขาการเตรียมฟนกอนการเปดชองทางเขา
•Temporary wall: Am, CR, GI, IRM
•Orthodontic band
•Gingivectomy
•Crown lengthening
ProcedureProceduress
Step 1 Radiograph
Step 2 Rubber dam application
Step 3 Pencil Access
Step 4 Cut through Center
Step 5 Step 5 EstablishEstablish outlineoutline formform(round diamond or carbide (round diamond or carbide bur with high speed bur with high speed handpiecehandpiece))
Step 6 Remove Step 6 Remove roof of pulp roof of pulp chamber chamber ((endoendolength round bur length round bur with low speed with low speed handpiecehandpiece))
Step 8 Locate canalorifice (endo explorer):reparative dentine is softer & lighter than normal dentine
TUG BACK in the area of canal orifice
Step 9 Check straightline access (endoexplorer or #10 file)
Irrigate often
ShapeShape ofof AccessAccess OOpeningpening
MaxMax insicorinsicorMaxMax molarmolarMandMand molarmolar
ShapeShape ofof AccessAccess OpeningOpening
MandMand incisorincisorMaxMax && mandmand caninecanineMaxMax && mandmand premolarpremolar
Error in Access PreparationError in Access Preparation
UnderextendedUnderextended preparationpreparationOverextended preparationOverextended preparationGougingGougingPerforationPerforationDisoriented Disoriented ((เปดทางเขาไมตรงตําแหนงเปดทางเขาไมตรงตําแหนง))
Failure to remove caries or Failure to remove caries or faulty restorationsfaulty restorations
UnderextendedUnderextended prepprep
Missed canalsMissed canalsTooth Tooth discolorationdiscoloration
UnderextendedUnderextended prepprep
Perforation or Perforation or ledge caused by ledge caused by failure to complete failure to complete convenience formconvenience formTotal loss of Total loss of instrument controlinstrument control
Overextended preparationOverextended preparation
Weakening coronal Weakening coronal tooth structure: tooth structure: Coronal fractureCoronal fracture
GougingGouging
Accumulate debrisAccumulate debrisInconvenient to Inconvenient to instrumentationinstrumentation
DisorientedDisorientedMisinterpretation of Misinterpretation of angulationangulationFaulty cavity has been preparing Faulty cavity has been preparing in full crownin full crown