ACCESS CAVITY
DR KAMRUNNAHAR

INTRODUCTION
ROOT CANAL PREPARATION IS FREQUENTLYCONSIDERED THE MOST IMPORTANT ANDCHALLENGING STEP
DURINGROOT CANAL TREATMENT.

IT INVOLVES USING MECHANICAL ANDCHEMICAL MEANS TO:
❑ REMOVEPULPAL TISSUE,
❑ REDUCEMICROBIAL LOAD, AND
❑ ENABLEAPPROPRIATE OBTURATION OF THE RADICULAR SPACES.

DEFINITION OF ACCESS CAVITY
PREPARATION
ACCESSCAVITY PREPARATION IS DEFINEDAS AN ENDODONTIC CORONAL PREPARATION WHICH ENABLES
UNOBSTRUCTED ACCESS TOTHE CANAL ORIFICES,
ASTRAIGHT LINE ACCESS TO APICAL FORAMEN,
COMPLETE CONTROLOVER INSTRUMENTATION AND
ACCOMMODATES OBTURATION TECHNIQUE.

PYRAMID OF ENDODONTICS

PRE-OPARATIVE X-RAY EVALUATION
• MORPHOLOGY OF THE TOOTH
• ANATOMYOF ROOT CANALSYSTEM
• NUMBER OF CANALS
• CURVATURE ANDBRANCHING OF THE CANALSYSTEM
• LENGTHOF THECANAL
• POSITION AND SIZE OF THE PULP CHAMBER AND ITS DISTANCE FROM OCCLUSAL SURFACE
• POSITION OF APICAL FORAMEN
• CALCIFICATION,RESORPTION PRESENTIF ANY

KEY STEPS TO CONSIDER IN ACCESS
PREPARATION
• VISUALIZATIONOF THEINTERNAL ANATOMY
• EVALUATIONOF THECEMENTOENAMEL JUNCTION AND OCCLUSAL TOOTH ANATOMY
• PREPARATION OF THE ACCESSCAVITY THROUGH THELINGUAL AND OCCLUSAL SURFACES
• REMOVAL OF ALL DEFECTIVE RESTORATIONS AND CARIES BEFORE ENTRYINTO THE PULP CHAMBER
• REMOVAL OF UNSUPPORTED TOOTH STRUCTURE
• PREPARATION OF STRAIGHTLINE ACCESS CAVITY WALLS
• INSPECTIONOF THEPULP CHAMBER WALLS & FLOORS
• TAPERINGOF CAVITYWALLS AND EVALUATIONOFSPACE ADEQUACY FORA CORONAL SEAL

OBJECTIVES
• DIRECTSTRAIGHT LINE ACCESS TO THE APICAL FORAMEN.
• COMPLETE DEROOFING OF PULP CHAMBER.
• CONSERVESOUND TOOTH STRUCTURE AS MUCH AS POSSIBLE
• PROVIDEA POSITIVE SUPPORT FOR TEMPORARY FILLING

ERRORS OF ACCESS

GUIDELINES OF ACCESS CAVITY
❑ PREPARATIONOF THE ROOT CANAL SYSTEMSTARTS WITH PREPARATION OF A PROPERLY DESIGNED
ACCESSCAVITY.
❑ BEFOREINITIATING ACCESS CAVITY PREPARATION, CHECK DEPTH OF PREPARATION AND POSITION OF
PULP CHAMBER BY ALIGN- ING THE BUR AND HANDPIECE AGAINST THE RADIOGRAPH

PREOPARATIVE X-RAY EVALUATION

GUIDELINES…
❑ USE ROUND BUR FOR PENETRATING INTO PULP CHAMBER
❑ ONCE“DROP IN” INTO THE PULP CHAMBER IS OBTAINED, ROUND BUR ISMOVED INSIDE TOOUTSIDE IN
BRUSH-ING MOTION.
❑ FINISHINGAND FLARING OF THE PREPARATION ISDONE USING NONEND CUTTINGBUR.
❑ COMPLETE REMOVALOF CHAMBER ROOF
❑ ACCESSCAVITY IS PREPARED THROUGH THE OCCLUSAL OR LINGUAL SURFACE NEVER THROUGH
PROXIMALOR GINGIVALSURFACE.

INSTRUMENTS FOR ACCESS CAVITY
PREPARATION

LAWS OF ACCESS CAVITY PREPARATION FOR
LOCATING CANAL ORIFICES
• LAWOF CENTRALITY
• LAWOF CEMENTO-ENAMEL JUNCTION
• LAWOF CONCENTRICITY
• LAWOF COLORCHANGE
• LAWOF SYMMETRY
• LAWOF ORIFICE LOCATION:

LAWS OF ACCESS CAVITY PREPARATION

TESTS FOR LOCATING CANALS
✔ IN CASE OF VITAL PULP:
o DROPLET OF BLOOD AT ORIFICE OR
o ARED LINE WITHIN A GROOVE THAT ORIGINATES FROM ORIFICES
✔ IN CASE OF NON-VITAL PULP:
o AWHITE LINE THAT CANBE SEEN AS ONE TROUGH ALONGA GROOVE.

MECHANICAL PREPARATION CAN BE
DIVIDED INTO SIX MAIN PARTS:
1. PREPARATIONOF THE CORONAL ACCESS CAVITY
2. PREPARATIONOF THE PULP CHAMBER
3. IDENTIFICATION OF ROOT CANAL ORIFICES
4. PREPARATIONOF A SECONDARY ACCESS TOTHE ROOT CANALS ANDCORONALFLARING
5. PREPARATIONOF A GLIDE PATH TO THE APICAL FORAMEN
6. PREPARATIONOF THE MIDDLE ANDAPICAL PARTSOF THE ROOTCANAL.

MECHANICAL OBJECTIVES
I.CONTINUOUSLY TAPERINGFUNNEL FROM THE APEX TOTHE ACCESSCAVITY
II.CROSS-SECTIONAL DIAMETER SHOULD BE NARROWER AT EVERY POINT APICALLY.
III. THE ROOT CANAL PREPARATION SHOULD FLOW WITH THE SHAPE OF THE ORIGINAL CANAL.
IV.THE APICAL FORAMEN SHOULD REMAIN IN ITS ORIGINAL POSITION.
V.THE APICAL FORAMEN SHOULD BE KEPT AS SMALL AS PRACTICAL

BIOLOGIC OBJECTIVES
I.CONFINEMENT OF INSTRUMENTATION TO THE ROOTSTHEMSELVES.
II.NOT FORCING NECROTIC DEBRIS BEYOND THE APICAL FORAMEN
III. REMOVAL OF ALL TISSUE ANDDEBRIS FROM THE ROOT CANAL SPACE
IV.CREATION OF SUFFICIENT SPACE FOR INTRACANAL MEDICAMENTS.
V.COMPLETION OF PREPARATION IN ONE APPOINTMENT.