1. Restoration of endodontically
treated teeth.

2. Introduction.
The Endodontically treated teeth are more susceptible to fracture than unrestored vital teeth and also lack a lifelike translucency, thus requiring a specialized restorative treatment.

3. Addressing the problem ??? “LOSS OF THE TOOTH STRUCTURE”
In terms of:
Retentive features available
Liability to fracture

4. Therapeutic goals:
Improving the retentive quality
Improving the fracture resistance

5. Negative influence of RCT on remaining sound tooth structure:
Architectural Changes.
Reduction in the dentin toughness.
Moisture loss.
Biomechanical Changes

6. Architectural Changes
Loss of tooth Structural integrity
(decay, dental procedures and
endodontic therapy )
Fracture resistance of the tooth decreases
Recent studies have concluded that:
access cavity preparation are associated with 5% reduction in tooth stiffness
Loss of MR is associated with 46% reduction in tooth stiffness
Loss of 2 MR is associated with 63% reduction in tooth stiffness
Circumferential loss in tooth structure is liabiity to #.
dome shaped roof of pulp chamber

7. Reduction in the dentin toughness:
Moisture loss:
It has a minimal effect on fracture liability.
Reduction in the dentin toughness:
It has an insignificant effect on fracture liability.

8. Biomechanical Changes:
Proprioceptive feedback mechanism is lost after endodontic
treatment. This might subject endodontically treated tooth to
greater loads than a normal intact tooth.
Tidmarish showed that
a normal tooth is hollow laminated structure which
deforms under load but complete elastic recovery occurs
after physiological loading.

9. Loss of the coronal tooth structure is the main
cause of the loss of the strength

10. Pre treatment considerations:
Restorative considerations.
Periodontal evaluation.
Occlusal evaluation.
Muscle function considerations.
Esthetic considerations.
Endodontic evaluation.

11. Restorative considerations:
Restorability
Strategic importance
Last abutment to avoid removable prosthesis.
The teeth included as abutments in the fixed or partial dentures absorb more forces and thus need additional retention and protection against fracture and caries due to leakage.
Retentive qualities of the remaining tooth structure and the need of
added means of retention.

12. Periodontal evaluation.
Mobility evaluation. (grade III)
Proper periodontal treatment to improve the diagnosis
Gingival biotype (thin visible cervical discoloration).

13. Occlusal evaluation. Checking the occlusal relation.
Assessment of the occlusal stress distribution (favorable / unfavourable)
T scan .

14. Muscle function considerations
Assessment of the muscle tone (EMG)
Assessment of the Para functional habits
Assessment of the daily habits
Opposing occlusion “ natural, removable or fixed
(EMG)

16. Esthetic considerations.
This is of prime importance in anteriors
Use of esthetic posts(non metallic posts) glass fiber posts and zirconium posts in mutilated endo treated teeth.
Gingival biotype ..e.g thin biotype needs esthetic restoration (zirconium
post & all ceramic crowns).
Internal discoloration from trauma or previous RCT may need internal
bleaching +/- veneers or may need full coverage.

17. Endodontic evaluation.
The quality of the existing root canal should be evaluated in
terms of :
Length
Density (voids)
Adequate apical seal
Procedural errors (broken instrument or perforation) will
compromise the prognosis
+/- periapical lesion
+/- signs and symptoms in relevance to the quality of ttt
Type of root canal filling ,silver points should be replaced

18. Requirements of a tooth to accept a post and core
• Optimal apical seal
• Absence of fistula or exudate
• Absence of active inflammation
• No sensitivity to percussion
• Absence of associated periodontal disease
• Sufficient bone support around the root
• Sound tooth structure coronal to alveolar crest
• Absence of any fracture of root.

19. Teeth with QUESTIONABLE RCT or
compromised prognosis should be
retreated , otherwise no treatment
options to be considered.

20. Treatment planning for restoration of endo-treated teeth
Objectives:
Treatment simplification without compromising the prognosis.
Maximum conservation of the remaining tooth structure.

21. Factors affecting the treatment plan :
1- Amount of remaining tooth structure:
remaining tooth structure fracture liability.
It’s the most deciding factor for post and core construction.

22. post & core+ extracoronal restoration
Teeth with insufficient coronal tooth structure
Cuspal /coronal
coverage
post & core+ extracoronal restoration
If the marginal ridges are
destroyed especially in:
1-maxillary premolars(splitting)
Due to
Steep cusps
Developmental root concavities
Lower premolar wedging
2 posterior molars with large
restoration.
If the remaining amount of
tooth structure aren't enough to provide retention for a core&/ or crown.

23. 2- Anatomical position of the tooth
Posterior teeth are located close to muscle insertions and are
subjected to occlusal loads.
Therefor , they usually receive cuspal coverage, except
mandibular premolars and 1st molars with intact marginal ridges and a conservative access preparation.

24. 3- Functional loading :
Greatest functional loading exist if the tooth is used as distal abutment
for a RPD.( tipping & destructive torque.)
Coronal protection with or without post is indicated.
The least functional forces exist, in the presence of an opposing
complete denture.

25. Treatment options for anterior teeth
Intact
Intact but
discolored
Extensive tooth
structure loss
Not disclored
Not intended
for use as RPD or FPD abutment
Minimum
discoloration
Moderate
discoloration
Extensive
discoloration
Microabrasi-on
Non-vital
bleaching
resin
composite
Conservative restoration
with resin
composite.
Non-vital
bleach
Laminate
veneers
Post
Core
Extracoronal
restoration
Bleaching
Coronal
coverage

26. Treatment options for posterior teeth
Premolars
Molars
maxillary
Mandibular
Depends on the remaining tooth structure and FF
Cuspal or complete coronal coverage .

27. Key features of post& core system
1- adequate apical seal:
3-5 mm g.p apically to exclude accessory canals that may cause leakage.

28. 2- post length : 2/3 root length or at least equal to
clinical crown length.
Why ??????
Secure retention
Better resistance
Resist leverage exerted on coronal portion.

29. 3- Post material : • Be biocompatible and resist corrosion .
• Be less technique sensitive
• Have high strength and fatigue resistance
• Be visible radiographically
• Be easily retrievable
• Be esthetic
• Be with an elastic modulus as close as
possible to the dentin.

30. Post material Metallic posts Nonmetallic posts Co-Cr alloy
Stainless steel
Titanium and
titanium alloys
Carbon fiber
posts
ceramic posts
Zirconia posts
fiber reinforced
composite
elastic modulus
close to dentin.
Customable to
different situation
Adequate mecha-nica properties
• excellent esthetic
Very elastic
modulus than
dentin.
Flexural strength
(Resist functional
loading).
Flexural strength.
High rigidity&
hardness
elastic modulus
Far beyond dentin.
• excellent esthetic
elastic modulus
close to dentin.
High rigidity
easily retrievable
• non esthetic

31. 5- Adequate relative parallelism in mid root to enhance retention.
4- Post taper
Should confirm with the canal
configuration to avoid :
Weakening of root structure.
Perforations
5- Adequate relative parallelism in mid root to enhance retention.
6- Transitional zone should be given a gradual taper B post and custom made core to resist the
fracture.

32. 7 –The ferrule : Def. : A 360° collar of coronal sound tooth
structure extending vertically B finish
Line and post &core junction.

33. Functions of the Ferrule
Binding the tooth structure
together
Enhance resistance to
dislodgment .
Prevent root fracture during
function
Ferrule dissipates the forces that concentrate at the cervical area of tooth, thus it prevents
fracture of tooth

34. 8- Positive horizontal stop :
To prevent :
Over seating
Wedging
Tooth splitting (VRF)
9- rotation resistance
anti-rotational groove
Features of successful design of post and core. 1. Adequate
apical seal; 2. Minimum canal enlargement; 3. Adequate post
length; 4. Positive horizontal stop; 5. Vertical wall to prevent
rotation; 6. Extension of the final restoration margin onto sound tooth structure

35. 10- The core Core is the supragingival portion that
replaces the missing coronal tooth structure and forms the center of new restoration.
Basically, it acts as a miniature crown.
Core build-up materials available are:
• Dental amalgam
• Resin modified glass ionomers
• Composite resin
• Reinforced glass ionomers cement

36. Ideal requirements for a core material
• High Compressive strength to resist intraoral forces
• Biocompatibility
• High Flexure strength to present core dislodgement
• Ability to bond to tooth structure and post
• Coefficient of thermal expansion similar to dentin
• Dimensionally stable
• Compatible esthetics .

37. Composite Resins Advantages Disadvantages Excellent esthetics.
• Bonded.
• High tensile strength and the tooth can be prepared
for a crown immediately after polymerization.
• It has fracture resistance comparable to amalgam and
cast post and cores, with more favorable fracture pattern.
Disadvantages
• Composite shrinks during polymerization,
•Technique sensitive (isolation).
Eugenol interfere with polymerization.

38. Amalgam Core Advantages :
It has good physical and mechanical properties and
works well in high stress area.
• In many cases, it requires the addition of pins or other
methods to provide retention and resistance to rotation.
Dimensionally stable
Disadvantages :
Objectionable esthetics
Non adhesive
Technique sensitive (Placement can be clumsy when there is minimal
coronal tooth structure.and crown preparation must be delayed)

39. Cast Core
The core is an integral extension of the post and it does not
depend upon the mechanical means of retention on the
post. It prevents dislodgement of the core and the crown
from the post. But sometimes valuable tooth structure must
be removed to create path of withdrawal. Procedure is time
consuming and expensive

40. Glass Ionomer Cements
The glass ionomer materials, including resin-modified glass
ionomer, lack adequate strength and fracture toughness
as a build-up material and should not be used in teeth with
extensive loss of tooth structure. It is also soluble and sensitive
to moisture. When there is minimal loss of tooth structure
and a post is not needed, GIC works well for block out such as
after removal of an MOD restoration

41. Biomechanical criteria for evaluation of core materials
Bonding (Maximum to least)
Resin composites > glass ionomers > amalgam
Strength
Amalgam > resin composite > glass ionomers
Ease of use
Resin composites > amalgam > glass ionomers
Setting time
Resin composite > glass ionomers > amalgam
Dimensional stability
Amalgam > glass ionomers > composite resins

43. Ready made ceramic inserts
Endo Crowns
Zirconium based ceramic restorations, used to
restore mutilated endo treated posterior teeth.
Fabricated using CAD-CAM technique.
Ready made ceramic inserts
SONISYS
CERANA

44. THANK U

45. A teacher asked a student to write 55. Student asked: How?
Writing 55
A teacher asked a student to write 55.
Student asked: How?
Teacher: Write 5 and beside it another 5!
The student wrote 5 and stopped.
teacher: What are you waiting for?
student: I don't know which side to write the other 5!