These days we often come across mutilated or badly broken teeth in our practice. However various factors are involved for a better prognosis of such a teeth. This presentation mainly focuses on post and core treatment of such a teeth.

1. Dr. Nabid Anjum
PG 3RD YR
Department of Prosthodontics

2. • Introduction
• Historical Perspective
• Characteristics of Endodontically treated teeth
• Diagnosis and Treatment planning
• Restorative Decision-Making Protocol
• Restorative Materials and Concepts
• Master Article
 Post and Core - Principles,Classification , ,
Methodology and Complications
• Conclusion
• Critical Analysis
• References

3. INTRODUCTION
• Endodontic therapy is used routinely in contemporary dentistry, but a satisfactory
restorative solution is necessary after the root canal has been treated.
• Root-filled teeth are generally weakened by caries and subsequent restorative procedures.
• Loss of dental tissue, due to either caries or cavity preparation, reduces tooth stiffness and
fracture strength of the remaining tooth structure in proportion to the increase in cavity
width and depth.
• Endodontically treated teeth which are to be used as abutments in prosthodontic
reconstructions, must be judged carefully regarding their ability to withstand a higher load
than a single tooth normally is exposed to.

4. • An endodontically treated tooth (ETT) can resume full function and serve satisfactorily as
an abutment for a fixed or removable partial denture. However, special techniques are
needed to restore such a tooth.
• The special needs involve ensuring both adequate retention for the final restoration and
maximum resistance to tooth fracture, which can be collectively termed as anchorage (i.e
maintaining adequate strength of root).
• Today, both endodontic and prosthodontic aspects of treatment have advanced significantly,
new materials and techniques have been developed, and a substantial body of scientific
knowledge is available on which clinical treatment decisions are based.

5. HISTORICAL PERSPECTIVE
• 1728 – Pierre Fauchard described the use of “TENONS” which were metal posts
screwed into the roots of teeth to retain the prosthesis.
• 1745 – Claude Mouton published his design of a gold crown with a gold post that was to
be inserted into the root.
• 1830-1870 –Wood replaced metal as the material of choice for posts.
• 1871 – Harries introduced wooden posts. However, the wood would expand in the moist
environment to enhance retention of the dowel until, unfortunately, the root would often
fracture vertically.

6. • “Pivot crown” – a wooden post fitted to an artificial crown and to root canal.
• 1884 – Richmond crown
• Later 19th century, single piece post crown.
• 1930 – Custom Cast post and core replaced the one piece post crowns or the Richmond
crown.
• 1960’s – Prefabricated post – core systems introduced.
• 1990’s (Shillinburg 1997) – Widely used prefabricated post – core systems

7. CHARACTERISTICS OF ENDODONTICALLY TREATED TEETH
• The from caries/trauma or both.
• The from ET teeth is reported to be about 9% less
than teeth with vital pulp (GV Black, Helfer et al )
• Fractures are more common in pulpless teeth than teeth with vital pulps.
• Brittle ? →The dentine undergoes structural changes in the collagen cross
linking and water content after the endodontic treatment →
due to access preparation which may increase cuspal
deflection during function → Fractures
• Loss of proprioception.
• Coronal microleakage and Bacterial accumulation are often associated with ET
teeth.

8. DIAGNOSIS AND TREATMENT PLANNING
• Before any therapy is initiated, the tooth must be thoroughly evaluated to
ensure treatment success, this includes:
 Good apical seal
 No sensitivity to percussion or biting pressure
 No sensitivity to palpation
 No sinus tract
 No periodontal probing deeper than 3mm.
 No evidence of active inflammatory disease.
 No radiograph signs of apical periodontitis.

9.  Extent of underlying periodontal disease
 Adequate biologic width
 In cases with extensive coronal destruction
crown lengthening can be considered
 Presence of enough coronal tooth structure to
incorporate ferrule into cast restoration

10. • The amount and quality of the
remaining tooth structure.
• The anatomic position of the
tooth.(Anterior/Posterior)
• The occlusal and prosthetic forces
on the tooth.
• Whether it is going to be an
individual unit or to used as an
abutment.
Esthetic Evaluation
 The gingiva may transmit a
shadow of the dark root color
through the tissue.
 Metal, carbon or amalgam
dowels can result in
unacceptable gingival
discoloration.
 The translucency of all-ceramic
crowns must be considered in
the selection of dowel and build-
up materials.

11. RESTORATIVE DECISION - MAKING PROTOCOL
Remaining tooth structure:
• Depending on the remaining tooth structure, different treatment
planning can be purposed.
• There is a direct relationship between remaining tooth structure
and fracture resistance.
• “
”
• In the situations where greater coronal tooth structure is lost, a
post is necessary to retain a core, the presence of vertical tooth
structure will provide a ferrule effect that is important to long-
term success, contributing to load distribution, improving
stability and rotational resistance.

12. • Increasing the ferrule height, particularly on the palatal side, enhances tooth resistance.
However, for a more predictable restoration, a properly executed ferrule must be 1.5–2
mm high, especially on the palatal and buccal walls.
• If destruction of the tooth structure renders a sufficient ferrule unachievable, crown
lengthening or orthodontic extrusion should be performed.

13. Functional Requirement:
• The tooth placement in the arch is an aspect to be considered when selecting materials and
techniques to restore pulpless teeth because force is different in anterior and posterior
regions.
• Occlusal load is key to treatment planning for root filled teeth. It is important for the
clinician to understand whether the patient has acceptable function or occlusal dysfunction or
parafunction.
• In the case of excessive occlusal wear, more destructive loadings are expected, which can
predispose compromised root filled teeth to fracture or other types of failure such as post
fracture, debonding or composite core fracture.
• Understanding occlusal problems and planning an appropriate reinforcement of the tooth to
be treated may help to reduce future failure risk.

14. Residual Root Structure:
• In addition to the amount of remaining coronal tooth
structure, the amount of residual root is also significant.
• A 1 : 1 ratio has been recommended as the minimally
acceptable necessary for resisting lateral forces when the
periodontium is healthy and the occlusion is controlled.
• Long-term maintenance of a tooth with an unfavourable
crown-to-root ratio, due to the presence of reduced alveolar
bone support, might lead to increased mobility and possible
periodontal issues.

15. RESTORATIVE MATERIAL AND CONCEPTS
• Conventional methods of restoring teeth, which depend on mechanical retention, are being
replaced by modern methods which depend on adhesion.
• This shift was attributed to the increased popularity of the minimally invasive dentistry
philosophy, and the development of reliable adhesive systems, as well as the etchable
ceramics.
Abu-Awwad M. A modern guide in the management of endodontically treated posterior teeth. Eur J Gen Dent
2019;8:63-70.

16. DIRECT COMPOSITE RESTORATIONS
• When a minimal amount of coronal tooth structure has been lost after endodontic
therapy, a direct resin composite restoration may be indicated.
• Direct composite restorations have been placed in anterior teeth that have not lost tooth
structure beyond the endodontic access preparation.
• In such cases, the placement of a direct composite restoration offers an immediate
sealing of the tooth, which prevents coronal leakage and recontamination of the root
canal system with bacteria.
• They are contraindicated when more than a third of coronal tissue has been lost.

17. INDIRECT RESTORATIONS
• Ceramic or resin composite onlays and endocrowns
can also be used to restore endodontically treated
teeth.
• Whereas overlays incorporate a cusp or cusps by
covering the missing tissue, endocrowns combine the
post in the canal, the core, and the crown in one
component.
• Both onlays and endocrowns allow for conservation
of remaining tooth structure, whereas the alternative
would be to completely eliminate cusps and perimeter
walls for restoration with a full crown.
• Onlays, overlays, and endocrowns can be fabricated
from ceramic or resin composites processed in the

18. ENDOCROWNS
• Endocrown-type restorations are single prostheses fabricated from reinforced ceramics that
can be acid etched, indicated for endodontically treated molar teeth that have significant
loss of coronal structure.
• Endocrowns are formed from a monoblock containing the coronal portion integrated into
the apical projection that fills the pulp chamber space, and possibly the root canal
entrances.
• They are especially used in situations of excessive loss of coronal dental tissue and limited
interocclusal space, in which it is not possible to attain adequate thickness of the ceramic
covering on the metal or ceramic substructures.

19. FULL CROWNS
• When a has been lost by caries,
restorative procedures, and endodontics, a full crown may be the restoration of choice.
• To be successful, the crown and crown preparation together must meet five requirements:
1. The ferrule (dentin axial wall height) must be at least 2 to 3 mm.
2. The axial walls must be parallel.
3. The restoration must completely encircle the tooth.
4. The margin must be on solid tooth structure.
5. The crown and crown preparation must not invade the attachment apparatus.

20. POST AND CORE
A one-piece foundation restoration for an endodontically
treated tooth that comprises a post within the root canal and
a core replacing missing coronal structure to form the tooth
preparation. (GPT 8)
A post usually made of metal or fiber-reinforced composite
resin that is fitted into a prepared root canal of a natural
tooth; when combined with a core, it provides and
for an artificial crown. (GPT 9)
 Helps in retaining the core
 Helps in favorable distribution of the stresses through the
radicular dentin portion of the teeth to apex.

21. DECISION MAKING:
• If all the axial walls of the cavity remain and have a thickness greater than 1 mm, it is not
necessary to insert posts ,provided the tooth is not subjected to undue occlusal forces.
• In these cases, any type of definitive restoration can be considered.
• Treatment in cases involving the loss of 1 or 2 cavity walls does not necessarily require the
insertion of a post, a core followed by a crown is indicated.
Peroz et al . Restoring endodontically treated teeth with posts and cores—A review.Quintessence
Int.2005 Oct;36(9):737-46

22. • In cases where only 1 cavity wall remains, the core material has little or no effect on the
fracture resistance.Thus post is indicated.
• If the tooth has to be used as an abutment for fixed or removable partial dentures, crown
preparation will further decrease fracture resistance.
• For esthetic reasons, nonmetal posts are preferred for treatment of anterior teeth. In
posterior teeth, both metal posts and nonmetal posts are acceptable treatment options.
• The definitive restorations should be crowns in anterior teeth and crowns, onlays, or
overlays in posterior teeth.
Peroz et al . Restoring endodontically treated teeth with posts and cores—A review.Quintessence
Int.2005 Oct;36(9):737-46

23. • In cases of teeth with a high degree of destruction where no cavity wall
remains, the insertion of posts appears necessary to provide for core material
retention.
• Additionally, the ferrule effect has a great influence on fracture resistance,
especially in decoronated teeth.
Peroz et al . Restoring endodontically treated teeth with posts and cores—A review.Quintessence
Int.2005 Oct;36(9):737-46

24. • Teeth with minimal tooth loss: Coronal
Restorations
• Teeth more than 50% of remaining
coronal structure: Restored with crowns
• Teeth with 25 to 50 % of remaining tooth
structure : Restored with non –rigid posts
• Teeth with less than 25% of remaining
tooth structure: Restored with rigid posts
• Kurer H G classified the single
rooted pulpless:
Kurer HG. The classification of single-rooted, pulpless teeth. Quintessence Int.
1991;22:939–43.

25. MASTER ARTICLE:
1. Principles for Post & Core:
•Preservation of tooth structure
a) Preparation of the canal
b) Preparation of the coronal tissue
a) Post Configuration
b) Post length
c) Luting agents
a) Anti rotation feature
b) Crown bevel
c) Vertical Remaining tooth structure

26. 2. Classification of Post:
According to Walton and Torabinejad:
• Passive post
• Active post
• Custom made post
• Pre-formed post
- Metal (Stainless steel, brass, titanium)
- Non metal ( Carbon fibre, Fibre reinforced , Ceramic / Zirconia)
c) According to shape:
• Parallel post
• Tapered post
• Smooth post
• Serrated post
• Threaded post
summarized the ideal physical properties
of a post that include:
• Maximum protection of the root.
• Adequate retention within the root.
• Biocompatible / noncorrosive
• Maximum retention of the core and crown.
• Maximum protection of the crown margin cement seal.
• Pleasing esthetics
• Radiopaque

27. • In areas where coronal dentin has been completely lost, a small groove placed in the canal
can serve as an anti rotational element.
• The groove is normally located where the root is bulkiest, usually on the lingual aspect.
• Described as a band that encircles the perimeter of the residual tooth, has a crucial influence
on fracture resistance, especially in decoronated teeth.
The ferrule should be a minimum of 1 – 2 mm high,
have , ,
end on sound tooth structure and not invade the
attachment apparatus of the tooth. (Wagnield et al
2002)

28. 3. Factors Affecting selection of post:
Root
Length
Post
Length
Post
Width
Canal
Configu-
ration
Tooth
Anatomy
Post
Design
Post
Material

29.  ROOT LENGTH:
• The length and shape of the remaining root
determines the length of the post (Holmes DC
et al. 1996)
• The greater the post length, the better the
retention and stress distribution
• Short root use a short parallel-sided threaded
post.
 TOOTH ANATOMY:
• Root anatomy such as root curvature,
mesio-distal width, and labio-lingual
dimension dictates post selection.
• Gutmann (1992) reviewed the anatomic
considerations and stated that roots of
maxillary centrals and laterals, and also
mandibular premolars have sufficient
bulk to accommodate most post systems.

30.  POST LENGTH:
• A classic retrospective study of the clinical outcomes of restored endodontically treated teeth
by Sorensen and Martinoff (1984) indicated that longer posts were associated with higher
success rates.
• When the length of the posts equaled or was greater than the length of the clinical crowns, the
failure rate was 2.5%.
Shillingburg et al (1982) noted that making the post length equal the clinical crown
would cause post to encroach on the 4 mm “safety zone” of gutta percha on some
teeth.
• The post should be 2/3rd of the length of the remaining root.
• At least should be retained apically to ensure a good
seal.
• The post should end halfway between the crestal bone and root apex.
• Equal to or greater than the crown length of the restored tooth

31.  POST WIDTH:
 Post diameter and the remaining dentin are identified as variables that influence
the resistance of an endodontically treated tooth to fracture.
 Post width must be controlled to:
preserve radicular dentin, reduce the potential for perforations and to permit the tooth to
resist fracture.
• Stern and Hirshfeld (1973) proportionist approach suggest the post
width should not be greater than one third of the root width at its
narrowest dimension.
• Halle EB et al ( 1984) preservationist approach suggest that the post
should be surrounded by a minimum of 1 mm of sound dentin.
• Pilo and Tamse (2000) conservationist approach advocated minimal
canal preparation and maintaining as much residual dentin as possible .
Fernandes S A . Factors Affecting the Fracture Resistance of Post-Core Reconstructed Teeth: A Review. Int J Prosthodont
2001;14:355-363.

32.  CANAL CONFIGURATION AND POST ADAPTABILITY:
• Canal configuration aids in making a choice between a custom designed post and a
prefabricated post. (Ash M jr. et al. 1993, and Smith TC et al. 1997)
Circular canals – prepared to have parallel walls - parallel
prefabricated posts .
Elliptical canals/ Excessively flared canals - cannot be prepared to
give parallel walls - custom cast posts or tapered prefabricated
posts

33.  POST MATERIAL:
• To achieve optimum results, the material used for the post
should have physical properties similar to that of dentin, can
be bonded to the tooth structure, and biocompatible in the
oral environment (Deutsch AS et al; 1983).
has a modulus of elasticity that
is nearly identical to that of dentin, so, better
stress distribution.
• Base metal & Zirconium ceramic, has a high
modulus of elasticity, i.e . forces are transmitted
directly from the post to the tooth interface without
shock absorption.

34.  POST DESIGN:
• The available post designs can be classified according to their shapes and surface
characteristics.
• They may be parallel, tapered, or parallel and tapered combination.
• According to their surface characteristics, the posts are active or passive (Musikant BL et al;
1984).
• The active posts mechanically engage the dentin with threads, whereas the passive post
depends on the cement and its close adaptation to the canal wall for its retention.
Tapered Post:
 conforms to the natural root form and the canal configuration, thus
permitting optimal preservation of tooth structure at the post apex.
However it produces a wedging effect, stress concentration at the coronal
portion of the root, and lower retentive strength.

35. Parallel post :
Parallel sided post designs have been shown to increase retention and produce
uniform stress distribution along the post length.
Paralled threaded Post:
The post is parallel throughout its length except for the most apical portion,
where it is tapered.
 It permits preservation of the dentin at the apex achieves sufficient retention
because of parallel design.
If the available post space is short 5 to 6 mm, a more retentive active post is
indicated.
If the available post space is 8 to 9 mm and the canal is not funnel shaped, a
tapered post may be a better choice.

36. 4. Overall Guidelines for posts in pulpless single rooted tooth:
• Anterior teeth with minimal loss of tooth structure may be restored conservatively with a
bonded restoration in the access opening.
• A post and core is only indicated when the tooth is weakened by the presence of large or
multiple coronal restorations, presence of undermined marginal ridges, or if they require
form or/and color changes that cannot be affected by bleaching, resin bonding or laminate
veneers.

37. • Because of the shearing forces that act on them, anterior endodontically treated teeth are
restored with posts more often than posterior teeth.
• Custom-made cast posts and cores are the recommended post system for single-rooted teeth
when substantial coronal tooth structure is missing.

38. 5. Overall Guidelines for posts in pulpless molars :
• Preservation of coronal and radicular tooth structure improves the probability of success of a
restoration for a pulpless molar.
• Direct cores are potentially more conservative of tooth structure; consequently, they are usually
preferred over cast cores.
• When a post is required because of lack of adequate remaining coronal tooth structure, if more
than 60% is missing, it should generally be placed only in the largest canal; that is the
in the maxillary molar and the in the mandibular molar.
• When the molar is to be used as an abutment tooth, a post is commonly used.
Nayyar and Walton (1980) described the amalcore in which amalgam is placed into
the chamber and 2mm into each canal space.
This restoration has been successful in both laboratory and clinical studies (Nayyar A
et al; 1980)

39. • A custom cast post-and-core system can be used for molars, but problems commonly occur
with the for the casting, and a two-piece restoration is often
required.

40. 6. Methodology:
• Tooth preparation for endodontically treated teeth can be considered a three-stage operation:
 Using a warmed endodontic plugger or using a rotary instrument.
 Before removing gutta-percha, calculate the appropriate length of
the post.
 Avoid the apical 5 mm if possible. An absolute minimum of 3 mm of
apical fill is needed.
 Peeso-Reamers and Gates Glidden drills are often used.
 Make sure the instrument follows the center of the gutta-percha and
does not cut dentin.
 When the gutta-percha has been removed to the appropriate depth,
shape the canal as needed.

41. Before enlargement of the canal, the type of post system to be used for
fabrication of the post and core must be chosen.
 Prefabricated Post:
• Use a prefabricated post that matches standard endodontic instruments.
• Tapered post vs Parallel post
• Be especially careful not to remove more dentin at the apical extent of the
post space than is necessary.
 Custom made post:
• Use custom-made posts in canals that have a noncircular cross-section or
extreme taper.
• Often very little preparation is needed for a custom-made post.
• Be most careful on molars to avoid root perforation.

42. • After the post space has been prepared, the remaining coronal tooth structure is reduced for
the extracoronal restoration.
• Specific reduction depends on the type of crown that is planned.
• Ignore missing coronal tissue and prepare the remaining tooth structure as if the crown is
intact.
• Remove any unsupported tooth structure, but preserve as much of the crown as possible.
• Wall height is reduced proportionally to the remaining wall thickness.
• An antirotation groove if needed should be placed in the canal.

43. • Prefabricated Post :
• Custom made post: (Direct Technique)

44. • Custom made post : (Indirect Technique)
 An orthodontic ‘J’ shaped wire is selected &
coated with an adhesive
 Canal is lubricated.
 Fill canal with elastomeric impression material
using a lentulospiral
 Seat the wire and syringe in more impression
material to cover coronal preparation and insert
the impression tray
 Remove the impression and Pour the cast and
fabricate the post and core on the cast.

45. • Core Fabrication:
 It can be shaped in resin or wax and added to the post pattern before the
assembly is cast in metal. This prevents possible failure at the post-core
interface.
 The core can also be cast onto most prefabricated post systems.
 A third alternative is to make the core from a plastic restorative material
such as amalgam, glass ionomer or composite resin.
 Cast Core: Metal and Ceramic
 Plastic Core: Amalgam, Composite, GIC, RMGIC
High compressive strength
High tensile strength.
Ease of manipulation
Short setting time for cement
An ability to bond to both tooth and dowel.
Biocompatible
Direct pattern for
single rooted teeth

46. • The core is cast directly onto the post of
one canal.
• Into The other canals - prefabricated posts
are passed through holes in the core.
• One post (to which core is cast onto) is
roughened and rest are left smooth &
lubricated
• Fit prefabricated posts into the prepared
canals
• Build up the core
• Grip the smooth lubricated posts with
force and remove them.
• Remove the pattern, invest and cast, the
core with it.
Indirect pattern for Posterior teeth
Direct pattern for posterior teeth

47.  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.
 After the luting agent is placed in the canal, the post is coated with
the luting agent and inserted.
Several studies have concluded that endodontically treated teeth
were six times more likely to be lost if a crown was not provided and
the outcomes were better if two proximal contacts existed.

48. 7. Post Retrievality:
Maserann Technique:
•The method involves gripping the object through a tube or
trephine which acts as a tube-vice.This method is relatively
harmless to the tooth and periodontium.
Eggler post remover
•The Eggler device can be easily applied to anterior teeth and to most first premolar
teeth, but its size prevents it from being used in most second premolars and virtually
all molar teeth
 Ultrasonic scalers

49. 8. PROBLEMS AND COMPLICATIONS:
Post dislodgement Apical lesion and caries
fractures of posts
Root Fractures

50. CONCLUSION
• A pulpless tooth has commonly lost substantial tooth structure as a result of previous
restorations, dental caries, and the access preparation for endodontic therapy.
• Consequently, a pulpless tooth requires a restoration that conserves and protects the
remaining tooth structure.
• Use of post-and core restorations has changed markedly in the past several decades. The
evolution from wooden to metal to the most recent fibre ones or from the custom cast to
the pre fabricated ones, they have been very promising in restoring endodontically treated
tooth.
• Therefore, it is possible to achieve high levels of clinical success. Also, that the prognosis
of these teeth relies primarily on the application of sound rather
than on the materials used for the restoration.
Avoid bacterial contamination of the root-canal system
Provide cuspal coverage for posterior teeth
Preserve radicular and coronal tooth structure
Use posts with adequate strength in thin diameters
Provide adequate post length for retention
Maximize resistance form including an adequate ferrule
Use posts that are retrievable.

51. CRITICAL ANALYSIS
• Factors influencing Post/Dowel selection were not explained in detail.
• Methods of fabricating Posts were not given.
• No photographs were included.

52. • Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd edition. Chicago: Quintessence; 1997. p. 204.
• Schwartz RS, Robbins JW. Post Placement and Restoration of Endodontically Treated
Teeth: A Literature Review. J Endod 2004;30:289-301.
• S.M. Morgano et al. Restoration of endodontically treated teeth. Dent Clin N Am
2004;48: 397–416
• Sorensen JA, Engelman MJ. Ferrule design and fracture resistance of endodontically
treated teeth. J Prosthet Dent 1990;63:529-36
• Gochhring TN, Peters OA. Restoration of endodontically treated teeth without posts.
Am J Dent 2003;16(5):313–7.
• Abu-Awwad M. A modern guide in the management of endodontically treated posterior
teeth. Eur J Gen Dent 2019;8:63-70.