Access Cavity Preparation

By : Omid Dianat DDS, MS. Assistant Professor,

Shahid Beheshti Dental School

Endodontic Treatment

Access Preparation

Working Length

Canal Preparation

Obturation

Access Cavity

• (1) Attainment of straight-line access,

• (2) Conservation of tooth structure,

• (3) Unroofing of the chamber to expose

orifices and to remove pulp horns in

anterior teeth.

Straight-Line Access

• Improved Instrument

Control.

• Improved Obturation.

• Decreased Procedural

Errors.

Ledge Formation.

Apical Perforation.

Furcal (Stripping) Perforation.

• Tooth Structure

Removal. reduction of the dentin shelf

Conservation of Tooth Structure

• Minimal Weakening

of Tooth.

• Prevention of

Accidents.

Unroofing of Chamber and

Exposure

of Pulp Horns

• Maximal Visibility.

• Location of Canals.

• I mprove Straight-

Line Access.

• Exposure of Pulp

Horns.

ACCESS TECHNIQUES

ACCESS IN SPECIAL

SITUATIONS

• Caries

• Existing Permanent Restoration

porcelain

• Existing Temporary Restoration

• Difficult-to-Locate Canals

Delay Isolation

Exploratory Radiographs

Caries

Calcified Canals

Access cavity preparation through a ceramometal crown.

A, Diamond-impregnated, round instrument. B, After access outline is made

with the round diamond, an end-cutting or round-carbide bur cuts through the

metal. C, Access cavity prepared, allowing direct approach to the canals. D,

Test files placed without impingement on the access cavity walls.

Maxillary Central Incisor 100% 1 canal

Maxillary Lateral Incisor 100% 1 canal

Maxillary Canine 100% 1 canal

Endodontic Preparation of

Maxillary Anterior Teeth

A-perforation

B-gouging

C-gouging

D-pear shaped prep.

E-discoloration

F-ledge

G-perforation

H-ledge

5%

15%

Central

lateral

Central 25%

Lateral 30%

70% 10%

20%

Endodontic Preparation of

Mandibular Anterior Teeth

gouging

Errors in ant. Mandibular Teeth

D-Failure to explore E-discoloration F-ledge

Maxillary first premolar

57%

16%

12%

10%

Maxillary Second Premolar

Pulp Anatomy and Coronal Preparation

53%

22%

13%

11%

Endodontic Preparation of Maxillary

Premolar Teeth

Maxillary Premolar Teeth

ERRORS in Cavity Preparation

Mandibular First Premolar

Pulp Anatomy and Coronal Preparation

70%

4%

25%

Mandibular second premolar

85%

12%

3%

Endodontic Preparation of Mandibular Premolar Teeth

Pulp Anatomy and Coronal Preparation

Errors in Mandibular

Maxillary first molar

2 canal 60%

1 foramen

80%

2 Foramen

20%

Maxillary second Molar

38%

10%

Endodontic Preparation of Maxillary Molar

Teeth

Errors

Mandibular first Molar

60%

40%

70%

20%

10%

Mandibular second Molar

92%

5%

3%

40%

35%

25%

Endodontic Preparation of Mandibular Molar Teeth

Errors

Mandibular Third Molar

C Shape Canals

Rotary systems(access modification)

• Maxillary molars

mesiobuccal canals

• Mandibular molars

mesiolingual canals

Any Question??

Thank you for attention!