1. The document discusses considerations for restoring endodontically treated teeth including tooth type, remaining tooth structure, and need for post placement. 2. Key factors for post placement include adequate canal enlargement, post length equal to crown height or 2/3 root length, and post diameter less than 1/3 root width. 3. Both custom-made and prefabricated posts have advantages and disadvantages for retention and resistance form. Fiber posts provide properties similar to dentin to reduce stress.

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3. •Causes of Weakness of endodontically treated tooth :
•caries, endodontic treatment, and previous
restorations.
•Technique for restoration of RCT depends on:
•1-The type of tooth
•2- Remaining coronal tooth structure
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5. Considerations For Anterior Teeth:
•Not always need complete coverage by placing a
complete crown
•Extensive loss of coronal tooth structure or tooth
will be serving as an FPD or RPD abutment crown
or post &crown
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6. Disadvantages to the Routine Use
of a Cemented Post
•Placing the post requires an additional operative
procedure.
•Preparing a tooth to accommodate the post entails
removal of additional tooth structure.
•The post can complicate or preclude future
endodontic re-treatment that may be necessary.
Is post strengthening or weakening the tooth ?
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7. Considerations For Posterior Teeth
•Subject to greater loading cusps can be
wedged apart
•Complete coverage is recommended on teeth with high
risk of fracture
•A cast post-and-core when there is significant coronal
tooth loss
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9. A. conservation of tooth structure:
- During preparation of the Canal
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10. A. conservation of tooth structure:
- During preparation of coronal portion.
- 2 mm of coronal tooth structure post role in
fracture resistance
- ferrule: Extension of the axial wall of the crown apical
to the missing tooth structure
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12. FIGURE 12-12 ■ Effect of apical preparation on crown-to-root ratio. A, Schematic of extensively damaged
premolar tooth. Apical extension of the gingival margin would encroach on the biologic width (see Chapter 5).
This preparation has no ferrule. C, crown length; R, root length. B, Creating a ferrule with orthodontic extrusion
reduces root length (R′), whereas crown length remains unchanged. C, Surgical crown lengthening (see Fig. 6-
21) also reduces root length (R′) but increases crown length (C′). This results in a much less favorable crown-to-
root ratio, which may, in fact, weaken the restoration.
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13. B. RETENTION FORM
Anterior Teeth
Post retention is affected by:
. Preparation Geometry
. Post length
. Diameter
. Surface texture
. luting agent
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14. Preparation
Geometry Post length
The post should be no more than one third the
diameter of the root, with the root and walls at
least 1 mm thick
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15. Post Surface Texture.
A serrated or roughened post is more retentive
than a smooth one and controlled grooving of the
post and root canal considerably increases the
retention of a tapered post.
Luting Agent.
Adhesive resin luting agents have the
potential to improve the performance of post
and core restorations
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16. B. RETENTION FORM
Posterior Teeth
Retention is better provided by two or more relatively short posts
in divergent canals.
When more than 3 to 4 mm of coronal tooth structure with
reasonable wall thickness remains, use of a post in the root
canals for retention is not necessary.
When a post is not used, the chamber must provide
adequate retention for the core material.
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18. C. RESISTANCE FORM
Stress Distribution
Glass fiber posts have an elastic modulus
(flexibility) similar to that of dentin and therefore
result in lower stress concentrations than do
metal or ceramic posts; this concept is termed
monoblock.
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19. C. RESISTANCE FORM
Rotational Resistance
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20. •Removal of the root canal filling
•Enlargement of the canal
•Preparation of the coronal tooth structure
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23. Removal Of The Endo Filling Material
•Two Methods of Removing Gutta-percha:
• a. With a warmed plugger or condenser
• b. With a rotary instrument (sometimes used with
chemical agent such as chloroform)
•If the gutta-percha is old and has lost its
thermoplasticity, use a rotary instrument
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24. the post length should be equal to the height of the
anatomic crown (or two-thirds the length of the root),
but leave 5 mm of apical gutta-percha.
On short teeth, an absolute minimum of 3 mm of apical
fill is needed.
The post should be no more than one third the root
diameter with the root and walls at least 1 mm thick
circumferentially
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27. Enlargement Of The Canal
•For Prefabricated Posts
•Enlarge the canal one to two sizes with twist drill,
file and Peeso-reamer that matches the
configuration of the post
•Use a prefabricated post that matches standard
endodontic instruments
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29. Enlargement Of The Canal
•For Custom-made Posts
•Use custom-made posts in canals that have a
non-circular cross section or extreme taper.
•Be most careful on molars to avoid root
perforation.
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32. Preparation Of The Coronal Tooth Structure
•Residual coronal walls should be at least 1 mm
wide.
•Wall height is reduced proportionally to the
remaining wall thickness
•Remove all undercuts that would prevent
withdrawal of the pattern
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33. 1, Adequate apical seal
2, minimum canal enlargement
3, adequate post length
4, positive horizontal stop (to minimize wedging)
5, vertical wall to prevent rotation)
6, extension of the final restoration margin onto
sound tooth structure
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34. •The post is the rigid part that inserted snugly fit in
the prepared root canal, which provide retention
of the core material.
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35. •High strength
•Passively fit
•Good retention
•Should not weaken the tooth
•Radiopaque for best visual control
•Accurately fit to the prepared canal
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36. •The material of the post should resist corrosion
•Biocompatibility of the material (non-toxic, no
mutagenic or allergic reactions)
•Easy for Retrievability
•High esthetic demands
•Less time consuming &simple procedure
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37. •a)Custom – made posts:
• type IV gold or Nickel-chromium alloys,
•b) Prefabricated posts:
• Metallic( stainless steel, titanium)
•Non-metallic (fiber reinforced resin, glass-
fiber, ceramic)
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38. goldNiCr
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39. The Custom-made Post
•Indications:
•Canals of non-circular cross section.
•Canals of extreme taper or excessively flared
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40. The Custom-made Post
•Advantages:
•- High strength.
•- Better fit than prefabricated post.
•Disadvantages:
•Time consuming and complex procedure.
•Casting defects may lead to failure:
•- Undetected porosity fracture of the post.
•- Undetected nodules fracture of the root.
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41. The PREFABRICATED POSTS
•Advantage:
•Technique simplicity.
•Minimum adjustment is needed for seating.
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43. • - Tapered
• - Parallel-sided
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44. • - Smooth-sided
• - Serrated
• - Threaded
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45. •Metallic posts
•Non -metallic posts
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46. Metallic Prefabricated Posts
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48. Non-metallic Prefabricated Posts
ceramic
Woven-fiber
composite
Fiber
re-inforced
composite
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49. Non-metallic Prefabricated Posts
Non-metallic
Fiber
post
Carbon fiber
C-Post Quartz fiber
Glass fiber
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50. Glass fiber post Carbon fiber post
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51. Non-metallic Prefabricated Posts
Non-metallic
ceramic
Glass-ceramic Alumina-oxide zirconia
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52. Ceramic Post
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56. •A direct technique:
•using Auto polymerizing resin in the
patient's mouth.
•It is recommended for single canals.
•An indirect technique:
•It's fabricated in the dental laboratory.
•It's recommended for multiple canals.
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60. •Single piece casting
•Possible parallism between two prepared
canals
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61. •Two pieces cast post and core
•Interlocking core technique
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63. FIGURE 12-39 ■ A and B, Interim restorations made for endodontically
treated teeth by lining a polycarbonate crown with autopolymerizing resin. The post is made of metal wire
(orthodontic wire or a paper clip). C, Restoration seated.
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64. •The luting agent must fill all dead space within the
root canal system
•A rotary (lentulo) paste filler or cement tube is used to
fill the canal with cement
•Inserted gently to reduce hydrostatic pressure Voids
may be a cause of periodontal inflammation via lateral
canals.
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65. •Metallic posts:
•it can be either; casted metal, amalgam, composite,
or reinforced glass ionomer
•Non-metallic posts:
•Fiber posts.. Composite
•Zirconia posts…
• 2 piece.. Heat pressed or copy milled or composite
•1 piece.. Post and core
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67. •post can be retrieved with thin-beaked forceps
•Vibrating the post first with an ultrasonic sealer
•Drilling out of post
•hollow end-cutting tubes (or trephines) Masserann
technique
•Post removal by extractor
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68. post retrieved with thin-beaked forceps
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69. Retrievability
Drilling out of post
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72. REFERENCES
Contemporary Fixed Prosthodontics; FIFTH
EDITION; Restoration of the Endodontically Treated Tooth, 278
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