1. Post Diameter
The diameter of the post is dictated by the root canal anatomy.
A minimal dentin thickness of 1 mm around the post should be provided.
The width of the post should not be greater than one third of the width of the root at any point along the dowel.
Smaller posts not only conserve tooth structure, but also provide increased resistance to fracture compared with larger posts.

2. (A) too narrow (B) optimum size post (C) too large

3. Post Design Posts can be serrated, smooth, roughened or threaded.
Parallel, serrated posts are cemented into the canal passively. They are retentive and produce less stress in the root dentin than threaded systems

5. The Ferrule Effect
The ferrule is the circumferential ring of sound tooth structure that is enveloped by the cervical portion of the crown restoration.
A minimum sound dentine height of mm is required between the core and crown margins.
This should provide adequate resistance to the lateral forces imparted on the restored tooth.
Ideally, this ferrule should be continuous around the entire circumference of the tooth.

6. The Ferrule Effect
The ferrule provides bracing or casing action to protect the integrity of the root.

7. Requirements of An Ideal Post
Minimum preparation.
Resistance to fatigue.
Elastic modulus similar to dentin.
Non corrosive.
Retentive (post & Head).
Easy to adjust and fit.
Radiopaque.
Adequate material
Easy Removal

8. Types of Posts
Prefabricated Post
Cast Post
(wax pattern needed)

9. Prefabricated Post

10. Cast post direct waxing

11. Indirect impression technique

12. Cast Posts Advantages Preservation of maximum tooth structure
Provision of anti-rotational properties
Core retention
Less chances of vertical fractures during preparation
High strength
Disadvantage
Time consuming
complex procedure
Indications:
Elliptical canals
Flared canals

13. Prefabricated Tapered Posts
Advantages:
Conserves tooth structure
High strength and stiffness
Disadvantages:
Low retention
Longitudinal splitting of remaining root
Indications:
Small circular canals
Very tapered canals

14. Prefabricated Threaded Posts
Advantage
High retention
Disadvantages
Stresses generated in canal may lead to fracture
Does not conserve coronal and radicular tooth structure
Indication
Only when maximum retention is essential

15. Fiber Reinforced Post Advantage Esthetic Disadvantage low strength
Indication
when there is sufficient tooth structure
when there is no high occlusal loads

16. Fiber Post

17. CORE part

18. Materials Used For Core Build Up
Direct Placement:
Amalgam
Composite
Glass ionomer type II
Indirect Placement
Casting

19. Composite Core Advantages Good compressive strength Easy to manipulate
Rapid polymerization
Dentin bonding
Disadvantages
Polymerization shrinkage
Poor dimensional stability
Water sorption
Technique sensitive
Air bubbles and spaces
Indication
Excellent build-up material for posterior and anterior teeth if isolation assured

20. Amalgam core Advantages Reduced marginal leakage
Better dimensional stability
Better compressive strength
Better modulus of elasticity
Disadvantages
Mercury sensitivity
Low tensile strength
Corrosion with base metal
Indication
Molars with adequate coronal tooth structure

21. Glass Ionomer Core Advantages Anticariogenic Adhesive
Easy to manipulate
Disadvantages
Low resistance to fracture
Low retention to preformed post
Sensitive to moisture
Indication
Teeth with minimum tooth structure missing

22. Gingival management Retraction cord Gingivectomy Laser Electro-cautery
Rubber dam