ACCESS CAVITY

D2 1

Aims of Endodontic treatment

• Biologic aimsa) To remove all the debris support to bacterial growth

b) To destroy all micro--organisms from the root canal

• Mechanical aimsc) Prepare root canal space for three dimensional filling

d) To obturate prepared canal in order to completelyseal fromboth apical (at the cemento-enamel

junction) and coronal seal

D2 2

1.

7.

9.

Steps in root canal therapyPatient selection

2.3.4.5.6.

8.

10.

Tooth selectionIsolationAccess cavityCanal irrigationWorking lengthCanal preparationTrial fillingCanal obturationCrown restoration

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1.12.3.34.

Preparation of tooth

Remove carious dentine and bad restorations

Restore it with GICIsolate the crownDisinfected the crown and immediateenvironment

5. Adhere to surgically clean technique

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Objectives of Access cavity1. To remove the entire roof of the pulp chamber so that the

pulp chamber can be irrigated and cleaned the canalentrance exposed.

2. To avoid damage to floor of the pulp chamber for locatedroot canals orifices. Natural floor is having funnel shapeorifice tends to guide an instrument in to the canal.

3. To achieve direct--line access to the apical third of the rootcanals for proper instrumentation, irrigation, shaping,cleaning, drying and obturation.

4. To enable a temporary seal to be placed.5. To conserve as much sound tooth tissue as possible

compatible with above.D2 5

Guide lines for Access cavitypreparation

1. Visualization of the internal anatomy2. Evaluation of the cemento-enamal junction and

occlusal anatomy3. Removal of all defective restoration and caries4. Removal of unsupported enamel5. Creating direct line access to apical third

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Guide lines for Access cavitypreparation

6. Delay of isolation until all the canal orifices located7. Location, flaring and exploration of all the canal

orifices8. Inspection of the pulp chamber using magnification

and adequate illumination9. Tapering cavity walls and10. evaluation of space adequacy for coronal seal

D2 7

Visualization of the internalanatomy

X-ray• Position of the pulp chamber

• Degree of calcification• Number of roots• Number of root canals• Approximate canal length

Examination coronal and cervical anatomypalpation along the attached gingiva for root location &

directionAssessments choose the direction of the initial bur penitration

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Evaluation of the cemento--enamaljunction and occlusal anatomy

• Except maxillary molars, canal orifices areequidistant from line drawn in mesiodistaldirection through the pulp chamber floor.

• Except maxillary molars, canal orifices lie on aline perpendicular to a line drawn a mesiodistaldirection across the centre of the pulp chamberfloor.

• the pulp chamber floor is always darker in colorthan the walls

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Evaluation of the cemento--enamaljunction and occlusal anatomy

• The orifices of the root canals are always locatedat the junction of the wall and the floor

• The orifices of the root canals are always locatedat the angles in the floor- wall junction

• The orifices of the root canals are always locatedat the terminus of the root developmental fusionlines

Mandibular 2nd and 3rd molars are prone to have Cshape canal

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Removal of all defective restorationand caries

• All defective restoration should be removed beforeentry into the pulp chamber

– Open preparation is much easier to locate, irrigation,cleaning , shaping, drying and obturation.

– Restorative debris easily lodged in to the canals

• All caries should be remove before entering to thepulp chamber

– Prevent contamination of the canals

– Prevent contamination of the accidental perforations– Prevent leaking of irrigating solutions

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Removal of unsupported enamel

• Preparation of access cavity results weakercrown

• This will prone to fractures• After finishing access cavity clinician should

remove all unsupported enamel to assessrestorability and to prevent tooth fracture

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Creating direct line access toapical third

• Sufficient tooth structure should be removedfrom the pulp chamber wall to allow instrumentsto be placed easily into each canal orifices withoutinterference from the canal walls

• Root canal walls should guide the files not thepulp chamber wall

• If not procedural error may formed like ledgeformation, instrument separation, apicaltransportation

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Delay of isolation until all thecanal orifices located

• For crowded, rotated, fractured, calcified, heavilyfiled and crown and angled teeth should not isolatebefore locating canal orifices

• It is difficult to locate canal orifices for abovemention teeth

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Location, flaring and explorationof all the canal orifices

• With sharp endodontic explorer locate thecanals

• With pre-curved small K file explore the canal• Until working length is determined instrument

should be operated within the confines of thecanal system

• Always a lubricating agent should be used

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Inspection of the pulp chamberusing magnification and

adequate illumination

• To see internal land mark and color changesmagnification and light is essential

• Operating microscope is the best• At least magnifying loupes should be used

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Tapering cavity walls and

• Access cavity should have widest at occlusalsurface

• Occlusal forces not push the temporaryrestoration into the cavity

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evaluation of space adequacy forcoronal seal

• At least 3.5mm thick temporary material isneeded for proper coronal seal

• Glass ionomer and light cure compositerestoration enhance the coronal seal

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Non-vital tooth Initial access

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Cutting into the pulp Removal pulp roof

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Use of Briault probe

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Extension of access cavity

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Completed access cavity.

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Use of barbed broachRoot canal irrigation

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Direct line access

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Prepare coronal part with gate bur

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Tooth length Working length

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Non--vital posterior tooth

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Initial access Access to the pulp

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Withdrawal actionSmoothening walls

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Orifice enlargement

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Remove interferences Uses of gates bur

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Preparation of coronal two third

Number 3 Gates burNumber 2 Gates burNumber 1 Gates bur

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Direct line access Anti-curvature filing

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Access cavity Average length – 22.5mm Prepared canal

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4/28/2009

Access cavity Average length – 22.0mm

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Prepared canal

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4/28/2009

Access cavity Average length – 26.5mm

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Prepared canal

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4/28/2009

Access cavity Average length – 20.6mm

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Prepared canal

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4/28/2009

Access cavity Average length – 21.5mm

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Prepared canal

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4/28/2009

Access cavity Average length – 20.8mm

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Prepared canal

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4/28/2009

Access cavity Average length – 20.0mm

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Prepared canal

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4/28/2009

Access cavity Average length – 20.9mm

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Prepared canal

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4/28/2009

Access cavity Average length – 25.6mm

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Prepared canal

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4/28/2009

Access cavity Average length – 21.6mm

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Prepared canal

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4/28/2009

Access cavity Average length – 22.3mm

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Prepared canal

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4/28/2009

Access cavity Average length – 21.0mm

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Prepared canal

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4/28/2009

Access cavity Average length – 19.8mm

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Prepared canal

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4/28/2009

Access cavity Average length – 22.5mm

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Prepared canal

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