This presentation is all about restoration of endodontically treated teeth, prefabricated post and core, cast post and core, direct and indirect technique.

1. CUSTOM MADE POST & CORE
IN ENDODONTICS
Pressented By : Dr. Arpit Viradiya
Guided By : Dr. Sandeep Metgud
Dr. Prashant Shetty
Dr. Deepali Agrawal

2. Introduction
• The restoration of the endodontically treated
tooth is a subject that has been evaluated and
discussed widely in the dental literature.
• It is complicated by the fact that much or all of
the coronal tooth structure which normally
would be used in the retention of the
restoration has been destroyed by caries,
previous restorations, trauma, and the
endodontic access preparation itself.

3. • All the teeth that have undergone root canal
therapy will require some form of restoration to
enable them to function again.
• Because endodontic treatment removes the vital
contents of the canal, which subsequently leads
to reduction in elasticity and increased brittleness
of remaining tooth structure.
• The objective is to return them to full occlusal
and cosmetic function.

4. • This weakening leads to the need for strong
interior as well as exterior support that is
achieved by post core system.
• Often due to mechanical reasons, the
prepared tooth is reinforced by post core
systems.

5. Post or dowel
• It refers to a cylindrical or tapered object that
fits into the prepared root canal of a tooth and
is synonymous with the term post or
endodontic post.
• The post is defined as the segment of the
restoration inserted into the root canal to aid
in retention of a core component.

6. • Endodontic post or dowel is
usually cemented or threaded
into a prepared channel.
• It can be fabricated from metal
or from other non-metallic
substances.

7. • Functions:
– Retention of core
– Protection of remaining tooth structure

8. • TYPES OF POSTS
• Metallic posts
– Custom cast posts
– Pre fabricated posts.
• Passive.
– Tapered.
– Parallel.
• Active.
• Non-metallic posts
– Carbon fiber posts
– Tooth colored posts
– Fiber reinforced posts.
– Ceramic and zirconia posts

9. • Materials Used:
• Metals
– Custom-cast posts:
» Gold alloys
» Chrome-cobalt alloys
» Nickel-chromium alloys
– Prefabricated posts:
» Stainless Steel
» Titanium
» Brass
• Non-metals:
– Carbon-fiber
– Glass fiber
– Quartz fiber
– Woven Polyethylene fiber
– Ceramic and zirconia

10. Core
• Refers to a build up restoration, usually
amalgam/composite placed in a badly broken
down tooth to restore the bulk of the coronal
portion of the tooth to facilitate subsequent
restoration by means of an indirect
extracoronal restoration.
• It may serve as either final restoration or as a
foundation for a crown.

11. • Is defined as properly shaped and well
restored substructure which replaces missing
coronal structure and retain the final
restoration.
• Core replaces coronal tooth structure that is
lost and forms a bare that has sufficient bulk
and retention for final restoration.

12. • The core consists of restorative material
placed in the coronal area of a tooth.
• This material replaces carious, fractured or
otherwise missing coronal structure and
retains the final crown.

13. • Core materials:
– Cast core
– Amalgam
– Composite
– Glass ionomer cement
– Resin modified glass ionomer cement

14. • INDICATIONS :
– Where the natural crown of root-filled teeth
either has been lost or is extensively damaged.
– Where the root-filled tooth is to be used as bridge
abutment.
– Where a change in axial position greater than
1mm is required.
– In a crowned anterior endodontically involved
tooth, to reinforce the crown covered tooth at
cervical area susceptible to fracture.

15. – Loss of two proximal surfaces with a lingual
endodontic access opening which weakens the
tooth.

16. • Contraindications :
– Severe curvature of the root-eg: Dilacerations of the
root.
– Persistent periapical lesion
– Poor periodontal health
– Poor crown to root ratio
– Weak / fragile roots
– Teeth with heavy occlusal contacts
– Patients with unusual and occupational habits
– Economic factors
– Inadequate skill.

17. IDEAL REQUIREMENTS OF POST CORE:
• Posts should have as many of the following clinical
features as possible:
– Maximum protection of the root
– Adequate retention within the root
– Maximum protection of the crown marginal cement seal
– Pleasing esthetics, when indicated
– Radiopacity
– Be simple, safe, versatile, and reliable in clinical use.
– Not create stresses in the remaining tooth tissues during
preparation and cementation.
– Allow an even distribution of all functional stress

18. – Include provision to ensure appropriate support
and retention of the core.
– Include features of facilitate removal, if so
required, even after prolonged periods of clinical
service.
– Be made of bioinert material that resist corrosion
and other forms of deterioration in the mouth.
– Be widely and readily available at reasonable cost.
– Resist loosening and displacement due to occlusal
and other functional stress.

19. • Core materials: Requirements:
– Stability in wet environment
– Ease of manipulation
– Rapid, hard set for immediate crown preparation
– Natural tooth color
– High compressive strength
– High tensile strength
– High fracture toughness

20. – Low plastic deformation
– Inert (no corrosion)
– Cariostatic properties
– Biocompatibility
– Inexpensiveness.

21. CLASSIFICATION OF POSTS AND
CORES:
• According to Ingle
– Custom-cast Posts
– Prefabricated Posts
• Tapered, smooth-sided posts
• Parallel-sided posts
• Tapered, self-threading screws
• Parallel-sided, threaded posts
• Parallel-sided, tapered apical end posts

22. • According to Weine
– Custom-cast Posts
– Prefabricated Posts
• Tapered, smooth sided post systems
• Parallel-sided, serrated and vented posts
• Tapered, self-threading post systems
• Parallel- sided, threaded post systems
– Self-threading
– Threaded with use of matched taps
• Parallel-sided, threaded, split-shank post systems

23. • According to Shillinburg
– Custom-cast Posts
– Prefabricated posts
• Tapered, smooth-sided posts
• Tapered, serrated posts
• Tapered, threaded posts
• Parallel, smooth-sided posts
• Parallel, serrated posts
• Parallel, threaded posts

24. • According to Robbins
– Metallic Posts
• Custom-cast Posts
• Prefabricated Posts
– Passive Tapered Posts
– Passive Parallel Posts
– Active Posts
– Non-metallic Posts
• Carbon Fiber Posts
• Tooth Colored Posts

25. CUSTOM CAST POST
• Custom cast post has a long history of clinical
success
• Developed in the 1930’s to replace the one-
piece post crowns.
• This procedure requires casting a post and
core as a separate component from the
crown.
• It almost always requires minimum tooth
structure removal.

26. • This method requires two-appointment visits
and a laboratory fee.
• As it is cast in an alloy with a modulus of
elasticity as high as 10 times the natural
dentin; this possible incompatibility can create
stress concentration in the less rigid root,
resulting in post separation or failure.

27. • There are, however circumstances in which
the custom-cast post is the restoration of
choice, including, the following
– When multiple cores are being placed in the same
arch. It is more cost effective to prepare multiple
post spaces, make an impression and fabricate the
posts in the laboratory.
– When post and cores are being placed in small
teeth, such as mandibular incisors. In these
circumstances, it is often difficult to retain the
core material on the head of the post.

28. – When the angle of the core must be changed in
relation to the post. Prefabricated posts should
not be bent; therefore, the custom post best
fulfills this requirement.
– The traditional custom cast post core provides a
better geometric adaptation to excessively flared
or elliptical canals and almost always requires
minimum tooth structure removal.

29. – Custom-cast post and cores adapt well to
extremely tapered canals or those with a non-
circular cross-section or irregular shape and roots
with minimal remaining coronal tooth structure.

30. Advantages of pre-fabricated post-core
systems over cast post
• They are simple to use.
• Require less chair side time.
• Can be completed in one appointment.
• Are easy to temporize.

31. Major disadvantages of pre-fabricated
Post-Core systems
• The root is designed to accept the post rather
than the post being designed to fit the root.
• Their application is limited when considerable
coronal tooth structure is lost.
• Chemical reactions are possible when the post
and core materials are made of dissimilar metals.
• Attachments for removable prostheses cannot be
applied, unless a separate casting is fabricated to
place over it.

32. Advantages of cast post over Pre-
fabricated post-core systems
• They are custom fit to the root configuration.
• Are adaptable to large irregularly shaped
canals and orifices.
• Can be adapted to be used with pre fabricated
plastic patterns.

33. Disadvantages of cast-post
• Expensive
• Requires two or more appointments.
• Temporization between appointments is more
difficult.
• Risk of casting inaccuracies
• May require the removal of additional coronal
tooth structure

34. BIOMECHANICAL PRINCIPLES
• 1. CONSERVATION OF TOOTH STRUCTURE
• 2. RETENTION FORM
• 3. RESISTANCE FORM

35. CONSERVATION OF TOOTH STRUCTURE
• Root canal:
– When creating post space, the practitioner should
use great care to remove only minimal tooth
structure from the canal.
– Over enlargement can perforate or weaken the
root, which then may split during cementation of
the post or during subsequent function.
– The thickness of the remaining dentin is the prime
variable in fracture resistance of the root.

36. • Coronal tissue:
– As much of the coronal tooth structure should be
conserved as possible because this helps reduce stress
concentration at the gingival margin.
– The amount of remaining tooth structure is probably
the single most important predictor of clinical success.
– It has been shown experimentally that if more than
2mm of coronal tooth structure remains, the post and
design plays little role in the fracture resistance of the
restored tooth.
J Prosthet Dent 1990;64:515-19.

37. – Incorporation of this tooth structure within the
final restoration provides the ferrule.
– In extensively damaged tooth creating a ferrule
with orthodontic extrusion may be preferred to
surgical crown lengthening as, although the root is
effectively shortened, the crown is not
lengthened.

38. RETENTION FORM
• Post retention is defined as the ability of a
post to resist vertical dislodging forces.
• Retention of a post is affected by:
– Preparation geometry and post design.
– Post length.
– Post diameter.
– Surface texture.
– Luting agent.
– Number of posts.

39. • Post design and preparation geometry:
• Circular canals can be prepared with drills or reamers
to give parallel walls or minimum taper, allowing use of
parallel-prefabricated post.
• Elliptical or excessively flared canals cannot be
prepared to give parallel walls and require custom cast
posts or tapered prefabricated posts.
• Laboratory testing has confirmed that
– Parallel sided posts are more retentive than tapered posts.
– Threaded posts are the more retentive than smooth posts.
J Prosthet Dent 1995;73:139-44.

40. • Post length:
• Retention increases with increase in post
length.
• One study shows that retention increases by
more than 97% when post length equals or is
greater than crown length.
• However, this length must be well within
constraints of tooth length, canal morphology
and root diameter in the apical area.

41. • Various criteria for post length are:
– Post length should be equal the incisocervical or
occlusocervical dimension of the crown
– The post should be longer than the crown
– The post should be one and one-third the crown length
– The post should be half the root length
– The post should be 2/3rd of root length
– The post should be 4/5th the root length
– The post should terminate half way between crestal bone
and root apex
– The post should be as long as possible without disturbing
the apical seal.

42. • Post diameter
• Whether posts are cemented or threaded,
diameter makes little difference in retentive
ability.
• Instead, if the post diameter is increased, the
amount of remaining dentin between the post
and the external surface of the root is decreased.
• This diminished remaining dentin becomes an
area of high stress concentration under load and,
consequently, an area with a high potential for
failure.

43. • Therefore, increasing the diameter in an
attempt to increase retention is not
recommended.
• The smallest diameter post that is practical
should be used for a given clinical situation.
• Deusch et al determined that there was a six
fold increase in the potential for root fracture
with every millimeter the tooth’s diameter
was decreased.

44. • There are three schools of thoughts regarding
the post diameter
– Conservationist (Advocated by Mattison) : Post
diameter should be as narrow as possible
– Proportionist (Advocated by Stern and Hirschfeld)
: Diameter should not exceed 1/3rd root diameter
– Preservationist (Advocated by Halle) – Leaving at
least 1mm of sound dentin around post

45. Post space preparation width
(Shillingburg)
Reamer
Number
Diameter Teeth
1 0.7mm Mandibular incisor
2 0.9mm Maxillary first premolar
Maxillary second molar (DF)
Mandibular first molar (ML)
Mandibular second molar (MF, ML)
3 1.1mm Maxillary second premolar
Maxillary first molar (MF, DF)
Maxillary second molar (MF)
Mandibular first molar (MF, D)
Mandibular second molar (D)
4. 1.3 mm Maxillary lateral incisor
Mandibular premolar
Maxillary molar (L)
5 1.5mm Canine
6 1.7 mm Maxillary central incisor.

46. • Surface texture:
• A serrated or roughened post is more
retentive than a smooth post.
• Roughening can be done with sandblasting.

47. • Luting agent:
• Any of the current luting cements can be
successfully used with a post if the proper
principles are followed.
• The most commonly used luting agents are: zinc
phosphate, resin cement, glass-ionomer and
resin-modified glass ionomer.
• However, Resin-modified glass ionomer cements
should be avoided as they expand on water
absorption and may cause root fracture.

48. • Generally, in the past, zinc phosphate was the
cement of choice, but, recent trend has been
toward resin cements because they:
– Increase retention.
– Tend to leak less than other cements.

49. • Number of posts:
– It is possible to place more than one post in teeth
with multiple roots.
– Additional posts may be used, where feasible, to
increase retention and retain core material,
especially in severely broken down teeth.

50. RESISTANCE FORM
• Resistance is defined as the ability of the post and
tooth to withstand lateral and rotational forces.
• One of the functions of a post and core
restoration is to improve resistance to laterally
directed forces by distributing them over as large
an area as possible.
• However, excessive preparation of the root
weakens it and increases the probability of
failure.
• The post design should distribute stresses as
evenly as possible.

51. • The influence of post design on stress distribution
has been tested and from these laboratory
studies, the following conclusions have been
drawn
– The greatest stress concentrations are found at the
shoulder, particularly inter-proximally and at the apex.
Dentin should be conserved in these areas.
– Stress is reduced as post length increases. But
excessive length reduces the thickness of dentin at the
apical area and hence the fracture resistance
decreases.

52. – Parallel-sided posts distribute stresses more
evenly than tapered posts, which can have a
wedging effect. However, parallel posts generate
high stresses at the apex.
– Sharp angles should be avoided as they produce
high stresses during loading.
– High stress can be generated during insertions of
smooth parallel-sided posts that have no vent for
escape of cements.

53. • Therefore, in these posts, longitudinal grooves
(vents) running along the length of the post should
be provided to allow escape of cement thus reducing
the hydrostatic pressure and generation of stress.
• Tapered posts are self-venting and generally do not
require vents.
• Threaded posts can produce high stresses during
insertion and loading, but they have been shown to
distribute stress evenly if the posts are backed off a
half-turn.

54. • Rotational Resistance:
– It is important that a post with a circular cross
section not rotate during function.
– Where sufficient coronal tooth structure remains,
this should not present a problem because the
axial wall then prevents rotation.
– When coronal dentin has been completely lost, a
small groove placed in the canal can serve as an
anti-rotational element.

55. • The groove is normally placed where the root is
bulkiest, usually on the lingual aspect.

56. • The Ferrule
• Rosen in 1961 described the extracoronal brace
(ferrule) and defined it as “….a subgingival collar
or apron of gold which extends as far as possible
beyond the gingival seat of the core and
completely surrounds the perimeter of the
cervical part of the tooth. It is an extension of the
restored crown which, by its hugging action,
prevents vertical shattering of the root”.

57. • More recently, Sorensen and Engelman (1990)
defined Ferrule Effect as “…..a 360° metal
collar of the crown surrounding the parallel
walls of the dentin extending coronal to the
shoulder of the preparation. The result is an
elevation in resistance form of the crown from
the extension of dentinal tooth structure”

58. • The walls and margins of the crown covers
2mm of the axial walls of the preparation form
the ferrule.

59. • A properly executed ferrule significantly
reduces the incidence of fracture in the non-
vital tooth by reinforcing the root at its
external surface and also by dissipating force
that concentrates at the narrowest
circumference of tooth.

60. Clinical Technique
• Removal of the Endodontic Filling Material
– It is recommended that the root canal system
should first be completely obturated and then
space made for a post.
– A post cannot be placed if the canal is filled with a
full length silver point, so these must be removed
and the tooth re-treated with gutta-percha.
• The two commonly used methods for gutta-
percha removal are:
– With a heated endodontic plugger.
– With a rotary instrument.

61. • Though previously it was thought that rotary
instruments would disturb the apical seal,
recent research has shown that both methods
can be safely used to remove gutta-percha
without disturbing the apical seal when 5mm
of gutta-percha is retained apically.
• Controversy exists regarding the timing of
removal of gutta-percha after endodontic
treatment.
• It was believed that removal should be
delayed by 1 week, as intermediate removal
should disturb the apical seal.

62. • Now, it has been shown that adequately
condensed gutta-percha can be safely
removed immediately after endodontic
treatment.
• If doubt exists about the endodontic
treatment, removal should be done after 1
week.
J Endod 1996;22:583-5.

63. Removal with rotary instruments:
• Gutta-percha can be removed
with GG drills, Peeso reamers,
Parapost-drills and other
commercially available burs.
• When rotary instruments like burs
or drills (B & C) are used, it should
be ensured that the instrument
follows the gutta-percha and does
not engage the dentin otherwise
perforation can occur.

64. • For this reason GG drills and Peeso reamers
(A) are preferred as their non-cutting tips keep
them centered on the gutta-percha (the path
of least resistance).
• Technique:
– Choose a Peeso reamer slightly narrower than the
canal.
– The depth of insertion is determined by
superimposing the Peeso reamer over the
radiograph of the tooth being restored.

65. – Set the stopper at the level of incisal
edge of adjacent teeth.
– Carefully remove the gutta-percha
and avoid cutting the root dentin.
– Often only a part of the root canal
fill need be removed with a rotary
instrument, and the remainder can
be removed with the heated
condenser.
– Once removal reaches the
appropriate depth shape the canal
as needed.

66. Removal with a heated endodontic
condenser
• In this method a heated endodontic plugger
or an electronic device is used to remove the
gutta-percha.
• This method is commonly used when gutta-
percha is to be removed right after obturation
as there are minimal chances of disturbing the
apical seal.

67. • Technique:
– Before removing gutta-percha calculate the
appropriate length of the post.
– As a guide, the post length should be equal to the
height of the anatomic crown or two-thirds the
length of the root, whichever is greater, but 5mm
of apical gutta-percha should be left.
– In short teeth, compromises must be made. An
absolute minimum of 3mm of apical fill is needed.
– If this cannot be achieved without having a very
short post, then prognosis of the tooth is
impaired.

68. – Avoid the apical 5mm if possible as curvatures and
lateral canals are found in this segment.
– The instrument is gauged for length against a
preoperative radiograph and the stopper is set at
the level of incisal edge of adjacent teeth.
– Apply rubber dam to prevent aspiration of
instrument.
– Select an endodontic condenser large enough to
hold heat well but not so large that it binds
against the canal walls.
– The instrument is heated till it is red hot, inserted
into the gutta-percha and is quickly withdrawn.

69. – This sears off the gutta-percha.
– If condenser it kept for a longer time or is not
heated well the gutta-percha will stick to the
instrument resulting in its being pulled out when
the condenser is withdrawn, thus disturbing the
endodontic seal.
– If the gutta-percha is old and has lost its
thermoplasticity, use a rotary instrument.

70. Enlargement of the Canal
• This is accomplished with,
Peeso reamers or a low speed
drill.
• The purpose is to remove
undercuts and prepare the
canal to receive an
appropriately sized post
without excessively enlarging
the canal.

71. • Before starting canal preparation, remove any
existing restorations, caries, bases and thin or
unsupported walls of tooth structure while,
preserving as much tooth structure as possible.
• Often very little preparation will be needed for a
custom-made post.
• However, undercuts within the canal should be
removed and some additional spacing is usually
necessary.
• Set the stopper on the instrument to the
predetermined length.

72. • Gradually enlarge the canal (in
0.2mm increments) to the size
that has been determined for
that tooth.
• Enlargement should not be
greater than one-third the
diameter of the root at the CEJ
(A) and there should be a
minimum thickness of 1.0mm of
tooth structure around the post
at mid-root and beyond (B).

73. • If anti-rotational resistance is
required use a no. 170 bur to
make a key way or groove in
the orifice of the canal.
• Place it in the area of greatest
bulk. It should be cut to the
depth of the bur (approx.
0.6mm) and up the canal to the
length of the cutting blades of
the bur (approx. 4mm)

74. Preparation of Coronal Tooth
Structure
• Ignore any missing tooth structure and
prepare the remaining tooth as though
it was undamaged.
• The facial surface (in anteriors) should
be adequately reduced for good
esthetics.
• Remove all undercuts that will prevent
removal of pattern.
• Preserve as much tooth structure as
possible.

75. • Prepare the finish line at least
2mm gingival to the core.
• This establishes the ferrule.
• For custom-made post and core
restorations, place a contra bevel
with a flame-shaped diamond at
the junction of the core and tooth
structure.

76. • The bevel provides a metal collar
around the occlusal circumference of
the preparation (in addition to the
ferrule) in bracing the tooth against
fracture.
• It also provides a vertical stop to
prevent over-seating and wedging
effect of the post.
• Complete the preparations by
eliminating sharp angles and
establishing a smooth finish line.

77. Post Fabrication
• A custom-made post can be cast from a direct
pattern or an indirect one.
• A direct pattern utilizing autopolymerizing
resin is recommended for single canals
whereas an indirect procedure is more
appropriate for multiple canals.

78. Direct procedure
• Trim a 14-gauge solid plastic sprue so
that it slides easily into the canal to
the apical end of the post preparation
without binding.
• Cut a small notch on the facial portion
to aid in orientation during subsequent
steps.
• Mix acrylic resin monomer and
polymer to a runny consistency.
• Lubricate canal with petroleum or any
other lubricating agent, on cotton
wrapped on a Peeso reamer.

79. • Fill the orifice of the canal as full as
possible with acrylic resin applied with a
plastic filling instrument.
• Alternatively:
– In the doughy stage, roll the resin into a thin
cylinder, introduce it in the canal and push it
to place with the monomer-softened sprue.
• Seat the monomer coated sprue
completely into the canal.
• Make sure the external bevel is
completely covered with resin at this
time.

80. • Trying to cover it later may disturb the fit of the
post.
• When acrylic resin becomes tough and doughy,
pump the pattern in and out to insure that it will
not lock into undercuts.
• As the resin polymerizes, remove post from canal
and make sure it extends till the apical end.
• If required, additional resin can be placed at the
apical end and the post is reseated and removed.
• Any voids can be filled with soft dead wax e.g.
utilizing wax Reinsert and remove to ensure
smooth withdrawal.

81. • Slightly overbuild the core and
allow it to fully polymerize.
• Shape the core with carbide
finishing burs.
• Correct any small defects with
wax.
• A direct pattern can also be
made using inlay wax in a
similar manner.
• Add more resin or wax to form
the core.
• Shape it in the form of the
final preparation.

82. Indirect Procedure:
• Any elastomeric material will make an accurate
impression of the root canal if wire reinforcement
is placed to prevent distortion.
• Cut pieces of orthodontic wire to length and
shape them like the letter J.
• Verify the fit in each canal. It should fit loosely
and extend to the full depth of the post space.
• Coat the wire and tray with adhesive; gingival
retraction would be needed for subgingival
margins.

83. • Use a die lubricant to lubricate canals and
facilitate removal.
• Using a lentulospiral, fill the canals with elastic
impression material.
• Seat the wire to full depth, syringe in more
impression material around the prepared teeth
and insert the impression tray.
• Remove the impression, evaluate it, and pour the
final cast.

84. • In the cast, trim a loose fitting plastic post or
sprue to fit the preparation till the apical end
without binding, make a notch for orientation.
• Use the impression as a guide to aid in
orientation.
• Apply a thin coat of sticky wax to the plastic post
and add soft inlay wax in increments.
• It is best to start at the most apical end and make
sure that the post is correctly oriented as it is
seated to adapt the wax.

85. • When post pattern is made, add wax to form
the core.
• Use the impressions as a guide to evaluate
whether the wax pattern is completely
adapted to the post space.

86. Investing and casting:
• The post-core pattern is sprued
on the incisal or occlusal end.
• 1.0 to 2.0cc of extra water is
added to the investment and a
liner is omitted to increase the
casting shrinkage.
• This results in a slightly smaller
post that does not bind in the
canal, and it also provides space
for the cement.

87. • A tight fit may cause root fracture.
• When resin is used, the pattern should remain
for 30 minutes longer in the burnout oven to
ensure complete elimination of the resin.

88. Provisional Restorations
• After endodontic treatment, if a cast post and
core is planned, a provisional crown with
attached temporary post can be fabricated for
the teeth with limited supragingival structure.
• A provisional restoration is also needed while
the post and core is being fabricated to
prevent drift of adjacent and opposing teeth.

89. • Fitting a wire paper clip (e.g. or orthodontic
wire) into the prepared canal or using a
temporary post available with proprietary post
systems can do this.
• Restoration is then conveniently fabricated
with autopolymerizing resin; after that
temporary crown can be given.

90. • The final post, core and crown should be
fabricated as soon as possible, because
microleakage can contaminate the post space
and endodontic fill.

91. Try-In and Cementation
• Check the fit of the post-core in the tooth by
seating it with light pressure.
• If it binds in canal or will not seat completely,
air abrade the post and reinsert it in the canal.
Relieve any shiny spots.
• The core portion of the casting should be
polished.

92. • If required, a vertical groove, from apical end
to contrabevel, can be cut in the post to
provide an escape vent for the cement.
• The canal should be cleaned with a cavity
cleaner to remove lubricant / temporary
cement which may inhibit set of resin cements
and decrease retention.

93. • Cement the post as for prefabricated posts.
• Modify the core if necessary.
• Make an impression for the final restoration.

94. FAILURE AND RETREATMENT
• Vire classified failure of endodontically treated
teeth are:
– Prosthetic failures.
– Periodontic failures.
– Endodontic failures.
• Of these, prosthetic failures occurred 59.4% of
the times, thus emphasizing the need to
properly restore endodontically treated teeth
to increase their longevity.

95. • For post and core restorations, failure rates
between 7% and 15% have been reported in
the literature (Torbjorner).
• The main factors that make endodontically
treated teeth more disposed to technical
failure are:
– Thin-walled, weakened roots unable to withstand
high stress.
– Reduced retentive surfaces resulting in high stress
levels in the cement.

96. • The main causes of post and core restoration
failure are:
– Dislodgement of post (loss of retention).
– Root fracture.
– Fracture of post.
– Caries.
– Periodontal disease.
• Careful, case selection, adherence to
biomechanical principles of post and core
restoration, appropriate post selection and
meticulous maintenance of oral hygiene on the
part of the patient can prevent this.

97. Conclusion
• Restoring the endodontically treated tooth
remains one of the most challenging problems
facing the restorative dentist.
• An uncomplicated and systematic decision
making process, based on universally accepted
philosophy and techniques, is necessary to
maximize chances for a successful restorative
outcome.

98. References