Post endodontic restoration/ orthodontic continuing education

POST ENDODONTIC
RESTORATION
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

• CONTENTS
1. Introduction
2. History
3. Restorative decision making
4. Differences between Vital & Endodontically treated teeth
5. Stress distribution patterns
6. Fracture predisposing patterns
7. Restorative classification for endodontically treated teeth
8. Biomechanical Considerations
9. Treatment planning
10. Foundation Restoration
11. Principles of Tooth Preparation and procedures
Post
Core

12. Temporization
13. Post fabrication
14. Cementation
15. Managing roots with open apex.
16. Root reinforcement
17. Conclusion
18. References

The goal of Endodontic and Restorative dentistry is to
retain natural teeth with maximum function and
aesthetics
So, for long term clinical success of the
endodontically treated teeth requires skilled
integration of restorative and endodontic disciplines.

HISTORY
• 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, they swelled
and caused roots fracture.

“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.

Restorative Decision Making
Anterior teeth:-
Minimal to moderate Coronal damage:-
Conservative treatment Resin composite, Reinforced GICs
JPD 1984;51
Significant Coronal Damage:-
Complete crown coverage
Custom cast post and core; Prefabricated post and core

Posterior Teeth :- Cuspal coverage required
Minimal damage:- Intact buccal/lingual walls; Minimal occlusal load
Conservative Treatment:- MOD Onlay
Classification of remaining tooth structure based
on no. of existing axial walls: Navmann et al 2002
Class I :-
- 4 remaining cavity walls
- Thickness greater than 1mm
No need for inserting posts
Class II & III
-Loss of one or two cavity walls
-Remaining hard tissue capable of supporting core-Adhesive system
-No indication of using a post
Class IV
-1 remaining cavity wall
Post Indicated
Class V
-No remaining cavity wall
Post Indicated; Ferrule effect is significant

Fractures in endodontically treated teeth have been understood to be
multifactorial in origin.

Endodontically Treated Teeth
1. Loss of tooth structure.
2. Altered physical characteristics.
3. Altered esthetic characteristics.
Loss of tooth structureLoss of tooth structure
a)a) Endodontic access cavity destroys the strucutural integrity provided by the coronal dentinEndodontic access cavity destroys the strucutural integrity provided by the coronal dentin
of the pulpal ceiling.of the pulpal ceiling.
b.b. Tooth stiffness reduction by 5 %.Tooth stiffness reduction by 5 %.

Are endodontically treated teeth brittle?
Vital dentin was 3.5% harder than dentin from contralateral endodontically treated teeth.
JOE1992; 18(7): 332-335
Reeh et al stated that endodontic procedures reduced the relative cuspal stiffness of premolar
teeth by only 5%,
An occlusal cavity preparation (20%) and an MOD cavity preparations
(63%).
The concept of “brittle” or weakened endodontically treated teeth has been attributed to loss of
tooth structure following trauma, caries, endodontic access, instrumentation.
AlthoughAlthough Helfer et alHelfer et al reported 9% lower water content of pulpless teeth versus vital teeth.reported 9% lower water content of pulpless teeth versus vital teeth.

Altered physical characteristics
a) Changes in collagen cross linking and dehydration of dentin.
14% reduction in strength and toughness.
Altered esthetic characteristics
Biochemically altered dentin modifies light refraction through the tooth and correspondingly
modifies its appearance.

Restorative classification of endodontically treated teeth:
CLASS
• One canal
• Two canals
• Three canals
Sub classification
a) Chamber space:-Interlocking; limited interlocking, Non-interlocking
b) Canal quality:-Shape: Segmented: straight/curved
Uniform: straight/curved
Size: Diameter: uniform/segmented
Length: Short/normal/long
Taper: Uniform: parallel/tapered segmented,parallel/tapered
Journal of esthetic dentistry 1998; 10(2): 75-83

Biomechanical considerations in restoring Endodontically treated
teeth
Journal of Prosthetic Dentistry 1994; 71(6): 565-567
. Maximal force occurs at external surface of root and decrease
to zero at the center of pulp space. Center of root is neutral area as regard to stress concentration.
A post therefore receives minimal stresses under occlusal load and consequently does little to reinforce root under
Stress distribution across root
in tooth under load

The key differences between intact tooth and tooth restored using
post–core are :-
(1)Occurrence of regions of stress concentration.
(2)Increase in the tensile stresses produced within the remaining tooth
structure of a post–core restored tooth.
(3) Increased flexure of the remaining reduced tooth structure.

The maximum shear stresses were primarily located at the post
cement/dentine interface, while the maximum tensile and von Mises
stresses were primarily located at the peripheral portions of the tooth.
This tensile and von Mises stresses culminate in increased risk of root
fracture, while the shear stresses culminate in increased risk of loss of
retention of the post.

Treatment Planning
A. Endodontic consideration:
B. Restorative consideration
C. Periodontal consideration

A. Endodontic consideration:
 Dense, uniform, three dimensional obturation (fluid impervious seal) of the root
canal system,0.5 to 1 mm from the radiographic apex of the root/roots is necessary.
 Unsatisfactory obturation should be re-treated.
B. Restorative consideration:
• A critical amount of solid coronal dentin is required, which must encase a coronal
restoration for structural integrity of the restored tooth.
a) Dentin axial wall height- At least 2 to 3mm
b) Axial walls must be parallel.
c) Restoration should completely encircle the tooth .
d) The margin should rest on sound tooth structure.
e) The crown and the crown preparation should not invade attachment apparatus.www.indiandentalacademy.com

Ferrule Effect:- (Eissman & Radke )
• A ferrule can be defined as a metal ring or cap put around the end of a tool to give added
strength.(Webster’s New World Dictionalry Springfield 1968)
• It is a 360 degree ring of cast metal extension at least 2mm apical to the junction of the core
and the remaining tooth structure.
• Ferrule created by the crown-encompassing tooth structure is more effective than a ferrule
that is part of the post and core
• Ferrule is desirable, but should not be provided at the expense of the remaining tooth/root
structure.
CORE FERRULECROWN FERRULEwww.indiandentalacademy.com

C. Periodontal consideration:
• Dimensions of the attachment apparatus range from 1.77
mm to 2.43 mm. This means that there should be an
absolute minimum of 2.5 mm distance between the
restoration margin and the crest of bone.
• Biologic width relates the amount of tooth structure
coronal to the osseous crest to the gingival attachment
apparatus.
• As a general rule, a minimum of 3 mm of sound tooth
structure coronal to the osseous crest will be necessary to
accommodate the connective tissue attachment, the
junctional epithelium, and the margin of the crown.
Defective tooth structure requiring margin placement in to zone B or C is
is an indication for periodontal crown lengthening or orthodontic extrusion.
(preferred)www.indiandentalacademy.com

Extrusion Distance = X+BW+1
X= Distance b/w alveolar crest and deepest
extent of destruction
BW= Biologicwidth=J.E(0.97mm)+C.T.A(1.07mm)

• Other Factors:
a) Tooth type, morphology, arch position, the occlusal and prosthetic forces applied to the
tooth and the amount of tooth substance loss.
b) The translucency of all ceramic crowns must be considered in the selection of dowel and
build up materials.

Restorative Treatment Planning
Considerations:-
 Amount of remaining tooth structure.
 Anatomic position of the tooth.
 The occlusal forces on the tooth.
 Restorative requirements of the tooth.
 The esthetic requirements of the tooth.
Timing the Restorative Treatment
 Good apical seal
 No sensitivity to pressure
 No exudate
 No fistula
 No apical sensitivity
 No active inflammation www.indiandentalacademy.com

Restoration of non vital teeth
Basic components:-
Apical endodontic seal
(5mm of Gutta-percha)
Dowel
Core
Final coronal restoration

Foundation Restoration: Post and Core
The post and core and their luting or bonding restoration together form a foundation restoration
to support a coronal restoration for the endodontically treated teeth. JPD 82:643,1999
POST:
The Post is a restorative dental material placed in the root of a structurally damaged tooth in
which additional retention is necessary for the core and the coronal restoration.
Functions:-
 Retention of the core and crown.
 Protection of the crown margin seal from coronal leakage.
 Pleasing esthetics, when desired.
 High radiographic visibility.
 Biocompatibility

CLASSIFICATION OF POSTS
(I) a. Prefabricated and Custom cast dowels
b. Metallic and Non metallic dowels
c. Rigid and Flexible dowels
d. Aesthetic and Non aesthetic dowels
(II) Barry et al Classification
1. Active posts
a. Parallel sided post positioned by tapping
b. Parallel self threading
c. Tapered self threading
2. Passive posts
a. Parallel smooth or serrated
b. Tapered smooth or serrated

(III) Weine’s Classification
a. Tapered smooth sided posts
b. Parallel, serrated and vented posts
c. Parallel threaded posts
d. Parallel, threaded, split shank posts
(IV) Ingle’s Classification
a. Tapered, smooth, cemented posts
b. Parallel sided cemented posts
c. Tapered self threading
d. Parallel, threaded inserted into prepared channels
e. Parallel sided with tapered apical end, cemented in to the channel
(V) Custom Cast Posts
Direct and Indirect techniquewww.indiandentalacademy.com

Passive retention posts:
Cast posts
Smooth tapered posts
Active retention posts:
Flexi posts
Kurer Anchor posts
III. Types of non-metal posts:
A. Based on composite materials:
1.Carbon Fibre posts:
Composipost
Carbonite
Endopost
Mirafit carbon
2.Silica Fibre posts:
Aesthetipost
Aesthetiplus
Light post
Snow post
Parapost fibre white
Light transmitting posts:
Light post
Luscent anchor post
Ribbon fibre posts:
Ribbond (Ribbond Inc.)

Rigid Post systems:-
Traditionally rigid post systems were metal and were either Custom cast or prefabricated.
Non-metal Posts Zirconia Posts
Zirconia posts are esthetic, adhesive alternatives to metal posts but also brittle and
difficult to retrieve from the canal.
Properties:-
Titanium,Gold and Zirconium posts are biocompatible.
Stainless steel contains nickel which is an allergen.
Cast gold,stainless steel are all radioopaque and easily distinguished on a radiograph.
Titanium and a well condensed gutta purcha share almost similar radio opacity.
Crown and Bridge alloys
Stainless steel
Titanium-Titanium alloy
Metal PostsMetal Posts

Recommendations:-
Rigid Posts:- Less than 3 to 4mm of vertical height or when
less than 25% of the tooth structure remains.
Non rigid posts:- When 25 to 50% of the tooth structure is
remaining.
If more than 50 % of the tooth structure is remaining, no post
is required.

PREFABRICATED PASSIVE
POST SYSTEMS

Pre fabricated posts:
Passive tapered posts:
a) Maintains natural pericanal tooth structure.
b) Mimics natural canal shape.
c) Tapered shaped provide least retention.
d) When there is adequate canal length for axial retention. (8 to 9 mm), and the
canal is not funnel shaped, the tapered post is an ideal choice.
e) Especially useful in the restoration of maxillary premolars, due to their thin, fragile,
fluted, tapered root form

Passive parallel posts:
• Greater retention.
• Clinically: successful history.
• Pericanal tooth structure has to be removed.
• Indicated when there is increased need for retention when the preparation of the
parallel canal space will not jeopardize the root integrity in the apical one third.
Active post:
a) Threads of the post actually engage or screw into the pericanal dentin.
b) V-Lock (Brasseler) and Flexi-post (Essential dental systems) have performed well
in laboratory investigations.
c) Indicated when increased retention is required in a short canal space.

PARA POST SYSTEM
They are passive, parallel, vented posts made of stainless steel or Titanium.
Three Designs
(a) Original Parapost (b) Para post plus (c) Unity System
(i) It has a vertical groove cut through the length of its serrations, allowing axial
venting.
(ii) The transfer of occlusal forces of the tooth occurs through the cement layer.
(iii) Cement retention is gained by horizontal serrations on the Original para
post , spiral flutes and grooves on ParaPost Plus and raised diamond
pattern on the Unity post.

BOSTON POST SYSTEM (Goldsman and Nathanson)
a) It resembles parapost system without the vertical venting channel.
b) 99.6% Titanium
c) It is a passive post, depends upon horizontal serrations and cementing
medium for retention.
PARKELL PARALLEL POST SYSTEM
a) Stainless steel passive, vented serrated post.
b) It has an anti rotational lock which fits on to the seat produced on the root.
c) It has a plastic core burn out pattern available for cast pattern

PREFABRICATED ACTIVE POST
SYSTEMS

ACTIVE POSTS
• The active posts engage the root dentine with threads they must always be
cemented with a luting cement.
Self-threading posts
Self-threading posts have a shank (shaft) that is fractionally narrower
than the post channel.
a) Dentatus Screw Post

(b)Flexi Post

Radix Anchor System

Pretapped Posts
KURER POST SYSTEM
(a)It has a high frequency thread around a parallel-sided shank.
(b) After post space preparation counter-thread on the internal aspect of the
post hole is prepared with a thread cutter.
(c) Root Facer which flattens the root face onto which the head of the post
seats. This unfortunately removes coronal tissue, which is important in
creating a ferrule.

• WHICH POST DESIGN PRODUCES THE GREATEST
RETENTION?
• Tapered cemented posts are the least retentive. Cemented, parallel-sided posts with
serrations are more retentive than cemented, smoothsided parallel posts. Threaded
posts are most retentive.
• RELATIONSHIP BETWEEN POST FORM AND THE
POTENTIAL FOR ROOT FRACTURE
• All types of threaded posts produce the greatest potential for root fracture(7%),
compared with tapered cemented posts (3%) and parallel cemented posts (1%).

Non Rigid Posts:
CLASSIFICATION
Carbon Fibres Silica Fibres Polyethylene
Endo post
Carbonite system
Mirafit carbon
Snow post
Fibre white
Mirafit white
Glass Fibre Quartz Fibre
Aesthetic post
Style post
Ribbond
Construct

CARBON FIBRE POSTS:-
• Introduced by Duret and associates(1990) in France.
• They consist of continuous, unidirectional, pyrolytic carbon / graphite fibres
reinforced in an epoxy resin matrix with 64% carbon.
TYPES:-
a) ENDOPOST:- Narrow parallel sided cylindrical posts(1 to 1.2mm) used for
retention of core materials in narrow-diameter roots such as molars or mandibular
incisors.
b) CARBONITE SYSTEM :-Parallel sided with a 3 mm conical tip. Available in
three diameters- 1.2mm, 1.35 mm and 1.5mm, with a single bur for each size.

Carbon Fibre Post

SILICA FIBRE POSTS:
TYPES- GLASS FIBRE AND QUARTZ FIBRE:
GLASS FIBER POSTS
Glass fibers have a lower elastic modulus than carbon / graphite fibers. These posts can
be made of different types of glasses.
a) SNOW POST :- It is composed of 60% longitudinally arranged Silica Zirconium
glass fibres in an epoxy resin matrix.
It is cylindrical in shape with a 3 degrees taper. The taper is 4-6 mm long. Available
in 1, 1.2, 1.4, and 1.6 mm diameters along with matching burs.
b) PARAPOST FIBRE WHITE :- Designed to complement and extend the existing
parapost system, fiber white has longitudinally arranged glass fibers.
Post is parallel has a removable colour coded ring around the head for identification.
Available in four diameters – 1.14, 1.25, 1.4 & 1.5 mm.

The Opaque Fiber
White Post

Quartz Fibre:-
TYPES :-
• I. AESTHETI POST:- These posts retain the central core of carbon fibre bundle
surrounded by quartz fibers arranged longitudinally.
• II. AESTHETI PLUS POST: - Belong to the next generation of aesthetic posts
and is composed entirely of quartz fibers.
• III. LIGHT POST: - A translucent quartz fibre post designed to permit light curing
materials to be used for leading curing light in to the canal.
• All of these variations are produced in the same shapes and sizes as the original
Composi post. RTD have recently introduced a series of posts with a double taper.
• STYLE POST: - Parallel sided, tapered end quartz fibre post system. This is
compatible with its metal prefabricated M-P post system and is produced in 4
diameters. www.indiandentalacademy.com

Translucent quartz-fibre posts, The DT light-post and
The Luscent anchor postwww.indiandentalacademy.com

3. WOVEN-FIBRE COMPOSITE MATERIALS/ POLYETHYLENE FIBRE
MATERIALS:
They are cold gas plasma treated, polyethylene woven fibres embedded in conventional
resin composite, they are advocated for corono radicular stabilization of pulpless
teeth.
Disadvantage similar to those of fibre reinforced epoxy resin post system-Inferior
strength combined with undesirable flexibility.

CORE
The core consists of restorative material placed in the coronal area of the tooth. The
core replaces carious, fractured, or missing tooth coronal structure and retains the
final restoration.
Desirable physical characteristics:-
a) High compressive strength
b) Dimensional stability
c) Ease of manipulation
d) Short setting time
e) Ability to bond to the tooth and post

CORE MATERIALS
• Amalgam has a long history of success. Its strength has been confirmed in
laboratory studies in both static and dynamic loading.
• However it possesses several disadvantages:
– Dark colour potentially lowers the value of all ceramic restorations.
– Causes a grey halo at the gingival margin.
– Low early strength (15-20 minutes wait before core preparation.)
– Messy to prepare.
– Irreversible staining of the gingival margin during preparation.

Glass Ionomer Cement
Advantages:
Ease of manipulation
Fluoride release
Chemical bonding
Disadvantage:
Low fracture toughness (fracture toughness - materials ability to resist crack
propagation)
Attempt to increase the fracture toughness; silver reinforcement has been added to
Glass Ionomer cement. Unfortunately this material also has low fracture
toughness:
 These materials should be used in posterior teeth in which more than 50% of the
coronal tooth structure remains.


Composite resin
• Available as light cured, autopolymerized and dual cure formulations.
• Major advantage: is the ability to be bonded to tooth structure and then to serve
as a substrate to which a ceramic crown can bonded.
• Laboratory studies have suggested adequate fracture toughness and compressive
strength in a static load test.
• However, it has not performed as successfully in dynamic load tests, that is
performed in a chewing machine.
• It appears to undergo plastic deformation.
• Not dimensionally stable in a wet environment. As it absorbs water, the core
expands and as it dries out, the core shrinks.

Cast Core
The core is an integral extension of the post, and the core does not depend on mechanical means
for retention on the post.
ADVANTAGES
a) The design prevents the dislodgement of the core and crown from the post and root when
minimal tooth structure remains.
b) Less removal of the tooth structure during fabrication.
DISADVANTAGES:-
a) Higher clinical rates of root fracture.
b) Technique sensitive and expensive.

Final Restoration:-
As a general rule, all endodontically treated posterior teeth and structurally damaged anterior and
posterior teeth should be restored with a crown.

PRINCIPLES OF TOOTH PREPARATION
1. Conservation of the tooth structure:-
Preparation of the canal:-
a) The thickness of the remaining dentin is the prime variable in
fracture resistance.
b) The root canal should be enlarged only enough to enable the post to
fit acuurately yet passively.

RETENTION TRIAD
POST LENGTH POST STYLE CEMENT TYPE

RESISTANCE TRIAD
CROWN BEVEL
VERTICAL REMAINING
TOOTH STRUCTURE ANTIROTATION

2. Retention form of a Post
a) Preparation geometry:-
Preparation walls desire parallelism or minimal taper, elliptical canal (6 to 8 degrees)
• Post surface texture:-
• Luting agent:- It is of great importance if the post is lose in the canal,
Adhesive resin have the potential to improve the performance of the post and core.
Zinc phosphate and Glass ionomer cement have similar retentive properties.
Composite resin and zinc polycarboxylate cements have slightly less.
d) Post length and diameterwww.indiandentalacademy.com

WHAT IS THE PROPER LENGTH FOR A POST?
A wide range of recommendations:-
(1)The post length should equal the incisocervical or occlusocervical dimension of the
crown.
(2) The post should be longer than the crown.
(3) The post should be one and one-third the crown length.
(4)The post should be half the root length.
(5) The post should be two-thirds the root length.
(6) The post should be four-fifths the root length.
(7) The post should be terminated halfway between the crestal bone
and root apex.
(8) The post should be as long as possible without disturbing the apical seal.

WHAT IS THE PROPER LENGTH FOR A POST?
Reasonable clinical guidelines for length include the following:
(1) Make the post approximately three-quarters the length of the root
when treating long-rooted teeth.
(2) When average root length is encountered, then post length is dictated
by retaining
5 mm of apical gutta-percha and extending the post to the gutta-percha.
(3) Whenever possible, posts should extend at least 4 mm apical to the
bone crest to decrease dentin stress.
(4) Molar posts should not be extended more than 7 mm into the root
canal apical to the base of the pulp chamber.

Average Crown
Length
Average Root
length
2/3 Root length 4 mm from Apex.
Maxillary Teeth
Central Incisor 10.8 12.5 8.3 8.5
Lateral Incisor 9.5 13.1 8.7 9.1
Canine 10.2 15.8 10.5 11.8
First Premolar 8.6 12.7 8.5 8.7
Second Premolar 7.5 13.5 9.0 9.5
First Molar 7.4 MF DF L
12.5 12.0 13.2
MF DF L
8.3 8.0 8.8
MF DF L
8.5 8.0 9.2
Second Molar 7.4 12.8 12.0 13.4 8.5 8.0 8.9 8.5 8.0 9.4
Mandiular Teeth
Central Incisor 9.1 12.4 8.3 8.4
Lateral incisor 9.4 13.0 8.7 9.0
Canine 10.9 14.3 9.5 10.3
First premolar 8.7 13.4 8.9 9.4
Second premolar 7.8 13.6 9.1 9.6
First Molar 7.4 M D
13.5 13.4
M D
9.0 8.9
M D
9.5 9.4
Second Molar 7.5 13.4 13.3 8.9 8.9 9.4 9.3

WHAT IS THE IDEAL POST DIAMETER
Instruments used to prepare posts should be related in size to root dimensions to avoid
excessive post diameters that lead to root perforation.

3.3. Resistance form of a PostResistance form of a Post
a) Stress distributiona) Stress distribution
One of the functions of the Post is to distribute the directed forces over as large anOne of the functions of the Post is to distribute the directed forces over as large an
area as evenly as possible.area as evenly as possible.
i)i) The greatest stress distribution is at the shoulder, particularly interproximally,The greatest stress distribution is at the shoulder, particularly interproximally,
Dentin should be conserved in these areas.Dentin should be conserved in these areas.
ii)ii) Parallel sided posts may distribute stress more evenly than tapered posts.Parallel sided posts may distribute stress more evenly than tapered posts.
iii)iii) Sharp angles should be avoided.Sharp angles should be avoided.
iv)iv) High stresses are generated during insertion, particularly with smooth, parallelHigh stresses are generated during insertion, particularly with smooth, parallel
sided posts that have no vent for cement escape.sided posts that have no vent for cement escape.
v)v) Threaded posts distribute stresses more evenly if the posts are backed off half aThreaded posts distribute stresses more evenly if the posts are backed off half a
turn.turn.

b) Rotational thickness
It is important that a post with a circular cross section should not rotate
during function.
GROOVE
a) If sufficient coronal structure is present rotation is prevented by a vertical coronal
wall.
b) If coronal dentin is absent then a small vertical groove in the canal serves as an anti
rotational element.It is located in the bulkiest area of the root.
Pins
Pins are used either alone or in combination with a postPins are used either alone or in combination with a post
Retention for the core materialRetention for the core material
Increase the resistanceIncrease the resistance
Maximum of 3 pins in anterior teeth if no coronal tooth structure existsMaximum of 3 pins in anterior teeth if no coronal tooth structure exists

Custom cast posts:
Long history of clinical success
Circumstances in which they are the material of choice include:
a) Multiple cores to be placed in the same arch (cost effective)
b) Usage in small teeth. Eg. Mandibular incisors where core build up is
difficult.
c) Angle of the core must be changed in relation to the post. (Prefabricated
systems should not be bent)
d) If a large core is supposed to be placed in high stress situations.

Maxillary first molars have deep concavities on the furcal surface of
94% of mesio-buccal roots,31% of disto-buccal roots, and 17% of palatal
roots.
Mandibular first molars have root concavities on the furcal surface of
all mesial roots and 99% of distal roots.
Maxillary first premolars have deep mesial concavities and slender
roots with thin dentine.
These anatomical restrictions should be kept in mind when restoring
such teeth.

Tooth preparation procedures:-
1. Removal of the root canal filling material to the
appropriate depth.
2. Enlargement of the Canal.
3. Preparation of the coronal tooth structure.

1. Removal of the root canal filling material to the
appropriate depth.
Q1.)How much gutta-percha should be retained to preserve the apical
seal?
Ans.) 4 to 5 mm should be retained apically to ensure an adequate seal.
Stopping precisely at 4 mm is difficult, and radiographic angulation
errors could lead to retention of less than 4 mm.Therefore, 5 mm of
gutta-percha should be retained apically
Goodacre and Spolnik , Journal Of Prosthodontics 1995;4

Removal of Endodontic filling material:-
The root canal should be completely obturated in the first place so as the lateral
canals get sealed.
A post cannot be placed if the canal is filled with a full length silver point, so
these must be removed and the canal should be retreated with gutta percha.
Methods to remove Gutta Percha
• Use of heated hand pluggers
• Use of Chemical solvents
• Use of rotary instruments

Use of heated hand pluggers
a) A heated instrument such as a lateral compactor can be inserted in
to the canal up to desired depth.
b) In narrow canals system B spreader is ideal for removal.
c) The hot instrument is carried in to canal and allowed to cool in the
canal for up to 7-10 seconds
d) An instrument such as BUCHANAN PLUGGER can be used to
vertically compact the remaining gutta percha in the root canal.

Canal filled with Gutta Percha
Hot Plugger placed in the canal, apical portion intact.
Serial widening of the canal
Verifying Fit

Use of Chemical Solvents
Organic solvents such as Chloroform,Eucalyptol or Xylol. Methyl
Chloroform and heated eucalyptol both have good solvent action and
are less toxic than chloroform ( Wennberg and Ostravik 1989 ).
Disadvantage:-
- Solvent evaporate from the softened Gutta percha and the latter
material shrinks
- It is difficult to control the depth of softening of the gutta percha and
potential leakage of the solvents in to the periradicular tissues.

Use of Rotary instruments
Rotary systems such as Peeso reamers, Gates Glidden drills are advocated for gutta
Percha removal.
Advantages of Peeso reamer:- Non cutting tip and Ability to remain centered in the canal
The frictional heat generated during the mechanical elimination of the gutta percha aids
in its removal by softening it. Softened mass is transported coronally by the direction
of the flutes, slight apical pressure will condense it apically, thus improving the
apical seal.
Kwan and Harrington, 1981.

PEESO REAMER SIZES
Reamer
Number
Diameter Teeth
1. 0.7 mm Mandibular incisor
2 0.9 mm Maxillary first premolar
Maxillary second molar (DF)
Mandibular first molar (ML)
Mandibular second molar (MF, ML)
3 1.1 mm 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 1.5 mm Canine
6 1.7 mm Maxillary central incisor

Coronal Tooth Preparation
a) Post and core fabrication can often best be done after the coronal tooth preparation
has been completed.
b) Type of single crown or retainer (all-metal, all-ceramic, metal ceramic) i.e., the
definitive restoration decides the reduction depths and form recommended for each
type of crown/retainer.

Pulp Chamber Preparation
The pulp chamber should be cleaned of any filling material prior to post
space preparation.

Enlargement of the Canal.
Root Selection for Multirooted Teeth
Primary roots:- Palatal roots of maxillary molars and distal roots of mandibular
molars.
Others:- Mesial roots of molars, Post length should be 3 to 4mm and
Width should be no larger than Peeso no.2 ( 1mm)

1. The canal is enlarged in size using the rotary instrument that corresponds to the final
dimension of the selected post.2. At least the apical half of the post should fit closely to the preparation. The coronal
half of the post may not fit as well because of root canal flaring.
3. If the root canal cannot be prepared to conform to the round shape of the post and
have adequate approximation to the root canal walls, then a custom-cast post may
be preferable.
4. The incisal/occlusal end of the post is shortened so that it does not interfere with
the opposing occlusion, but it must provide support and retention for the restorative
core material ( 2-3mm).
Prefabricated Cemented or Bonded Post/Restorative
Material Core

5. When metal posts are used, they can be bent coronally,if necessary, to align them
within the core material . Post bending is done outside the mouth with orthodontic
pliers.
6. If there is little or no remaining coronal tooth structure to provide resistance to core
rotation, an auxiliary threaded pin (TMS pins, minimum or regular) should be
placed into the remaining tooth structure

Temporization
As root canal treatment and final restoration are not finished in a single appointment,
Therefore, a tooth must be prepared for a sealing temporary.
Objectives of Temporizaion:
The restoration must
a) Seal coronally, preventing ingress of oral fluids and bacteria and egress of intracanal
medicaments.
b) Protect tooth structure until the final restoration is made.
c) Provide aesthetic requirements at times, but always as a secondary consideration to
providing seal.

Types of Temporary Restoration
1. Reinforced Zinc Oxide Eugenol Cement
2. Cavit
3. Light cured composite material ( TERM )
Techniques of Placement
•Coronal seal depends on the thickness of the material, a minimum of 3-4mm is required,
preferably 4mm to allow for wear.
•In anterior teeth, the access is oblique to the tooth surface, care must be taken to ensure
that material is at least 3mm in the cingulum area.
•A cotton is placed in the access cavity to prevent ingress of temporary material in the
root canals.
•Patient should avoid chewing on the tooth for an hour.www.indiandentalacademy.com

For severely broken down tooth,
At the first visit a Cusp overlay amalgam, Clayette or occasionally a well fitting
orthodontic band is cemented on the tooth which provides a durable temporary
restoration.
At the next appointment, a conventional access cavity is made, and the bulk of the
restoration is left in the place.

Temporary Dowels and Crowns
1. An Endopost is prepared in the same manner as for the impression to fabricate post
and core.
2. The non working end of the post is bent in a cane shape to fit the coronal portion of
the template.
3. Vaseline is applied on to the prepared tooth with a camel’s hair brush, if little tooth
structure remains, a small amount of saliva acts as a separating media.
4. Before the template is inserted in to its place, a portion of the a creamy mix of quick
setting acrylic is painted on the cane portion of the post by camel’s hair’s brush.
5. With the Endopost in its place, quick setting acrylic is poured in to the coronal
portion of the template. Patient is asked to close his mouth.
6. When the acrylic reaches a rubbery consistency, the patient is instructed to open,
template is removed, and the temporary restoration with the post is separated from
the temporary restoration by a plastic instrument.
The gross flash is cut off with the small scissors , while still in soft state, the restoration is
reinserted in to the preparation and allowed to set.

Ion Crown form for an Individual retainer
Selection of ion crown Endopost placement
Quick setting acrylic placement
Polished Temporary crown cemented

Lost coronal seal ?
• Management of potentially contaminated, filled root canals:-
1. Clean the pulp chamber thoroughly.
2. Penetrate the canal orifices up to 1/3rd
to ½ of the length of the canal.
3. Irrigate with NaOCl, place EDTA for 1 to 2 minutes and place 2%
chlorhexidine for approx. 2 minutes.
4. Dry the canal, fill the canal with Ca(OH)2 and place a sound temporary
filling.
5. Recall the patient after 1 to 2 weeks and, if symptom free, begin restoring
the tooth.

POST FABRICATION

Custom-cast post and core
Traumatically fractured central incisor after endodontic treatment
Indirect Technique

Prefabricated Posts

NON RIGID POSTS

GLASS FIBRE-SNOW POST SYSTEM

CEMENTATION
Any of the current luting cements can be used successfully with a post if the
proper principles are followed.
The most common luting agents are Zinc phosphate, Resin, Glass ionomer,
Resin modified glass ionomer.
Recent trend is favouring resin cements due to the following
a) Increased retention QI 2003;34
b) Less leakage JOE 2003;29
c) Short term strengthening of the root JOE 1984;10
The 4th
generation adhesive systems ( 3 step ) should be used as they provide a
better seal to radicular dentin than recent 5th
generation systems. Self cure
or dual cure systems are preferred.

Cementation of Posts
An attempt should be made to place the post in the canal after the canal
coated with cement to avoid air entrapment leading to voids.

MANAGING ROOTS WITH OPEN APEX
Treatment of non-vital,permanent teeth with wide open immature
apicies is difficult , as it is impossible to achieve an apical hard
tissue barrier against which a root canal filling can be compacted.

TREATMENT MODALITIES
1. Apexification:-It is a technique that induces apical closure by the
formation of mineralised tissue.
Calcium hydroxide in the form a non-setting aqueous suspension is the
material of choice.
Disadvantages:-
a) Long time required, the time taken for closure is variable,ranging from
five to 19 months. J Endod 1987; 13
b) Varying success rate of apexification has been reported as 74–96%.

One-visit apexification
An alternative to apexification over multiple visits has been the placement of a
biocompatible material into the apical part of the root canal.
Materials that have previously been tried are :-
a) Calciumphosphate ceramic
b) Surgicel with amalgam,
c) Freeze-dried cortical bone
d) Freeze-dried dentine and dentinal shavings.

• Mineral Trioxide Aggregate can be used as an apical barrier material for
root-end closure.
The material consists of fine hydrophilic particles of tricalcium silicate,
tricalcium aluminate, tricalcium oxide and silicate oxide. When mixed
with sterile water it forms a colloidal gel that sets within three to four hours.

Occasionally the post endodontic presentation of the canal may be too wide for
routine direct restoration.
The problem in restoring weakened roots is the fact that the remaining root
dentine is thin and therefore prone to fracture.
The Luminex light transmitting system (Dentatus) is used to rehabilitate this
canal to an ideal size and shape.
ROOT REINFORCEMENT

Procedure:
• Canal is reamed to the desired depth with a size matched reamer. The
reamer is correlated in size and shape to the corresponding light
transmitting post (LTP) and a luscent anchor.
• Light transmitting post is tried in and adjusted for length.
• Canal is then dried, etched and rinsed.
Bonding agent is applied in the canal and cured.•A microhybrid composite resin, Esthet X (Caulk, Dentsply) is injected into the
bonded canal and the light transmitting post is pushed into the uncured
composite resin to its full depth.www.indiandentalacademy.com

CONCLUSION
A pulpless tooth has commonly lost substantial tooth structure.
Consequently, an endodontically treated teeth requires a
restoration that conserves and protects the remaining tooth
structure. Although, there are many materials available for
providing almost perfect restoration but prognosis of the
pulpless teeth relies primarily on the application of sound
biomechanical principles rather than on the materials used for
the restoration.

REFERENCES

References:-References:-
Textbooks:-Textbooks:-
a)a) Endodontics:- Ingle, Bakland, 5th EditionEndodontics:- Ingle, Bakland, 5th Edition
b)b) Pathways of the pulp :- Cohen S,8th EditionPathways of the pulp :- Cohen S,8th Edition
c)c) Textbook of Endodontics – WeineTextbook of Endodontics – Weine
d)d) Operative dentistry- SummitOperative dentistry- Summit
e)e) Problem solving in endodontics- GutmannProblem solving in endodontics- Gutmann
f)f) Fixed Prosthodontics- Tyllman;Shillinberg;RosensteilFixed Prosthodontics- Tyllman;Shillinberg;Rosensteil
g)g) Endodontics in clinical practice- T.R Pitt FordEndodontics in clinical practice- T.R Pitt Ford

(1)“Restoration of the endodontically treated tooth”
J. William Robbins
DCNA 2002; 46:367-384.
(2)“Restoration of endodontically treated teeth: An overview of clinical
aspects.”
Pankaj Dhawan
Journal of IPS 2001 Oct; 1(3): 21-28.
(3)“Esthetic Post and core treatment”
George A. Freedman
DCNA Jan 2001; 45(1): 103-116.
(4)“Factors affecting retention of post systems: A literature review” Lawrence
W. Stockton
JPD 1999; 81(4): 380-385.
(5)“Biomechanical criteria for evaluating prefabricated post and core systems:
A guide for the restorative dentist”.
Charles T. Smith et al
Quintessence International 1998; 29: 305 –312.

(6)“The endodontically treated tooth” Restorative concepts and techniques.
Kenneth C. Trabert, et al.
DCNA 1984 Oct; 28(4): 923-951.
(7)“Biomechanical considerations in restoring endodontically treated teeth”.
David Assif et al.
JPD 1994; 71: 565-567.
(8)“Restoration of endodontically treated teeth: A review of literature” Stephen
I. Hudis
JPD 1986; 55(1): 33-38
(9)“Prefabricated dowels: A literature review.
JPD 1983; 49(4): 498-503.
(10)“Management of endodontically treated tooth Part I : Concept for
restorative designs”
Albert C. Goerig et al
JPD 1983; 49(3): 340-345. www.indiandentalacademy.com

Post endodontic restoration/ orthodontic continuing education

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