Managment of endodontic teeth / endodontic courses

Good morning
www.indiandentalacademy.com

MANAGEMENT OF
ENDODONTICALLY TREATED
TEETH
INDIAN DENTAL ACADEMY
Leader in continuing dental education

Contents
 Introduction
 History
 Changes in tooth when endodontically treatment
 Treatment planning
 Restorative decision making- factors influencing
basic components
 Ferrule
 Intracoronal posts
 Principles of tooth preparation
 Techniques of post space preparation
 Root reinforcing post
 Temporization www.indiandentalacademy.com

 Cementation
 Core fabrication
 Coronal radicular restoration
 Endodontically treated teeth
as abutments - factors considered
- tooth preparation
 Removal of existing posts
 Failures in posts
 Recent advances
 Conclusion
 References www.indiandentalacademy.com

Introduction
 Teeth that were once considered non restorable and
extracted are today treated endodontically and restored
of function
 Restoration of endo Rx teeth – replaces missing tooth
structure
maintains esthetics and
function
protects against fracture
prevents from infection

History
 Fauchard (1747) used maxillary anterior teeth for
anchorage when restoring single and multiple units.
He used posts made of gold/silver and a heat
softened adhesive “mastic’ to hold them in position.
 1830-1870 –Wood replaced metal as the material of
choice for posts- swelled and caused roots fracture.
 “Pivot crown” – a wooden post fitted to an artificial
crown and to root canalwww.indiandentalacademy.com

 G.V Black developed a porcelain faced crown
held by a screw inserted into the canal filled with
gold foil.
 Richmond crown, named after C.M. Richmond
(1884) is a dowel-retained crown with porcelain
facing.
 Davis crown named after Wallace Clydi. Davis is
a dowel with in the root canal over, which is,
cemented a porcelain tube tooth in direct contact

Changes in tooth when
endodontically treated
Altered
physical
characteristics
Altered esthetic
characteristics.
Loss of tooth
structure.

Loss of tooth structure
Endodontic access cavity destroys the strucutural
integrity provided by the coronal dentin of the pulpal
ceiling.
Tooth stiffness reduction by 5 %.
Are endodontically treated teeth brittle?
Attributed to loss of tooth structure following trauma,
caries, endodontic access, instrumentation.
Studies- 9% lower water content of pulpless teethwww.indiandentalacademy.com

Altered physical characteristics
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 itswww.indiandentalacademy.com

Best time to restore endodontically
treated teeth
Do not wait for extended periods of time after rct
Need to seal coronal orifice from contamination
Prevent fracture and caries
Studies- no diff in leakage of root canal filling material
when post space prepared immediately after
completing endo Rx

Good apical seal
No sensitivity to pressure
No exudate
No fistula
No apical sensitivity
No active inflammation

Treatment planning
Endodontic
consideration
Restorative
consideration
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.
Dentin axial wall height- At least 2 to 3mm
Axial walls must be parallel.
Restoration should completely encircle the tooth .
The margin should rest on sound tooth structure.
The crown and the crown preparation should not
invade attachment apparatus.www.indiandentalacademy.com

C. Periodontal consideration:
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, thewww.indiandentalacademy.com

Restorative Decision Making
 Anterior teeth:-
Minimal to moderate Coronal damage:-
Conservative treatment Resin composite, Reinforced GICs
Significant Coronal Damage:-
Complete crown coverage
Custom cast post and core; Prefabricated post and core
 Posterior Teeth :- Cuspal coverage required
If minimal damage i.e, intact buccal/lingual walls and minimal
occlusal load, the conservative treatment of choice will be a
MOD Onlay.

Classification of remaining tooth
structure based on no. of existing axial
wallsClass 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

Should crowns be placed on
endodontically treated teeth
 Crowns be placed on endo rx posterior teeth
having occlusal interdigitation with opposing teeth
 Crowns donot enhance clinical success of anterior
endo rx teeth
 Use limited to esthetic and functional requirements

Factors influencing type of
restoration
 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.

Basic components of
restoration
 Residual coronal and radicular tooth structure
 Post located in root- retains core
 Core located in pulp chamber and coronal area of
tooth- retains crown
 Coronal restoration
 Adhesive bonding agents/ traditional luting
cements www.indiandentalacademy.com

Coronal tooth structure-
FERRULE
Most important part of restored tooth is tooth itself.
Axial walls of crown engage the axial walls of prepared tooth forming
the ferrule.
Fracture resistance  significantly with  amount of sound tooth
structure and ferrule.
Ferrule is a band that encircles the external dimension of residual
tooth, similar to metal bands around and barrel.
Formed by walls and margins of the crown or by cast telescoping
coping encasing at least 2-3 mm of sound tooth structure.

Advantages of Ferrule:
reduces the fracture incidence in nonvital teeth by
reinforcing tooth at its external surface and
dissipating force that concentrates at narrowest
circumference of tooth.
resists lateral forces from posts and leverages
from crown in function and  resistance and
retention of restoration.www.indiandentalacademy.com

Requirements of ferrule:
• Dentine axial wall height must be at least 2-3mm
• Axial walls must be parallel
• Restoration must completely encircle the tooth
• Margin must be on solid tooth structure

 Crown and crown preparation must not invade
attachment apparatus.
So 4-5mm height and 1mm thick sound, supra bony
tooth structure should be available to
accommodate both periodontal biologic width and
restorative ferrule
 Insufficient tooth structure:-
Subgingival margin placement
Crown lengthening
Orthodontic extrusionwww.indiandentalacademy.com

Also, Crown lengthening- increases crown root ratio
increased leverage
 In absence of ferrule –
dentine bonding agent with an amalgam core
and direct stainless steel post - significant
increase in fracture resistance

•Pre rx data review
•Philosophy and purpose
•Post design and shape – various post
systems
•Post diameter
•Post length
Intra coronal posts and
dowels

Pre treatment data review
POST:
The dowel is a metal post rigid restoration placed in the
radicular portion of a non vital tooth
To retain restoration – post is necessary when insufficient
tooth structure remains to hold a restoration.
To protect remaining tooth structure they are used to direct
occlusal, lateral forces more apically.
Dowel must be designed in such away that it serves
retentive function without endangering the root /coronal
integrity

Philosophy and purpose
 The Post- 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
 Donot reinforce endo rx teeth
 Not necessary when substantial tooth structure
present

 protection from root fracture
 retention within root and retrievbility
 retention of the core and crown
 Protection from coronal leakage

 Pleasing esthetics when needed
 High radiographic visibility
 Biocompatibility
Preservation of remaining tooth structure

Post design and shape
(I) Prefabricated and Custom cast dowels
Metallic and Non metallic dowels
Rigid and Flexible dowels
Aesthetic and Non aesthetic dowels
(II) 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

(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

Prefabricated posts
Advantages
 They are simple to use
 Less time consuming
 Can be completed in one appointment
 Cost effective
 Remarkably strong
Disadvantages
 root is designed to accept a post rather than post being
designed to fit the root
 application is limited when considerable coronal tooth
structure is lost
 chemical reactions are possible when posts and core are
made of dissimilar metals.

PREFABRICATED PASSIVE POST
SYSTEMS

 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
Passive tapered posts:
Maintains natural pericanal tooth structure
Mimics natural canal shape
Tapered shaped provide least retention
When there is adequate canal length for axial retention (8 to
9 mm)
Maxillary premolars- tapered root form
. www.indiandentalacademy.com

Passive parallel posts:
Greater retention.
Clinically successful history.
Pericanal tooth structure has to be removed.

Tapered post
 Kerr endopost
 Ellman nuband
 Mooser
Parallel post
 Parapost
 Boston post
 Parkell parallel post (CI Kit)
Parallel side with tapered apical end
 Deggusa
 Unilek www.indiandentalacademy.com

Tapered smooth sided post
They are oldesing most widely used design.
Systems employing this configuration are Kerr
endopost, Ellmaninubond and Mooser post.
They are least retentive of all post designs.
used in teeth not subjected to high functional loads.

Parallel posts-
PARA POST SYSTEM
Passive, parallel, vented posts made of stainless steel
or Titanium.
Has a vertical groove cut through the length of its
serrations, allowing axial venting.
The transfer of occlusal forces of the tooth occurs
through the cement layer.

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

Parallel sided post with tapered apical end
provide greater retention than parallel posts confine
to tapered apical position of canal.eg deggusa ,
unitek
Because of taper, these posts are venting and easily
cemented
acts as wedges, the effect of wedging is related to
flare of post channel; greater the flare greater thewww.indiandentalacademy.com

PREFABRICATED ACTIVE POST
SYSTEMS

The active posts engage the root dentine with threads they
must always be cemented with a luting cement.
 Self threaded-
Tapered- Dentatus
Flexi post
Parallel sided- V lock
Radix anchor system
 Pretapped posts-
Kurer anchor post

Self-threading posts
have a shank (shaft) that is fractionally narrower
than the post channel.
a) Dentatus Screw Post

 (b) Flexi Post
 Split end design- collapses when screwed – less
stress

(c)Radix Anchor System
Twist drill , gauge to check fit ,root facer to produce
flat surface for post head, post mounted on driver
clockwise then quarter turn anti clockwisewww.indiandentalacademy.com

Pretapped posts-
KURER POST SYSTEM
High frequency thread around a parallel-sided shank.
After post space preparation counter-thread on the
internal aspect of the post hole is prepared with a
thread cutter.
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.www.indiandentalacademy.com

Drill, root facer, tapping device, threaded post with
driver

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

post form and the potential for root
fracture
 All types of threaded posts produce the
greatest potential for root fracture(7%)
 tapered cemented posts (3%)
 parallel cemented posts (1%).

Rigid post systems
Traditionally rigid post systems were metal and were
either Custom cast or prefabricated.
Properties:-
Titanium, Gold and Zirconium posts are
biocompatible.
Stainless steel contains nickel which is an allergen.
Cast gold, stainless steel are all radio opaque and
easily distinguished on a radiograph.
Titanium and a well condensed gutta purcha share
almost similar radio opacity.www.indiandentalacademy.com

Non rigid posts
 Carbon fibres- Endo post
Carbonite system
Mirafit carbon
 Silica Fibres - Glass Fibre- Fibre white
Mirafit white
Quartz Fibre - Aestheti post
Style post
 Polyethylene - 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.

(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.

GLASS
FIBRE QUARTZ
FIBRE
Silica fibre posts-

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.

QUARTZ FIBRE:-
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.
IV. STYLE POST: - Parallel sided, tapered end
quartz fibre post system.

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.www.indiandentalacademy.com

Post diameter
 THE CONSERVATIONIST
The instrumentation is limited to removal of
undercuts that prevent withdrawal of dowel patterns
 THE PROPORTIONIST
Optimal diameter of the dowel was one-third the
diameter of the root(Goodacre)
 THE PRESERVATIONIST
1 mm of sound dentin be maintained around the
entire circumference.

 As the post diameter increased - stress increased in the
tooth
 Mesial roots of mand molars and buccal roots of max
molars not to be used – perforation in furcation area
 Molar posts should not be larger than 7 mm
 Mand incisors- 0.6-0.7 mm
 Max central incisors, palatal root of max molars- 1.0 mm
 Rest of teeth – 0.8-0.9 mm

Post length
(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
Mandibular 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

Principles of tooth preparation

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

2. Retention form of a Post
(a) Preparation geometry:-
Preparation walls desire parallelism or minimal taper, elliptical canal (6 to 8
degrees)
(b) Post surface texture
(c) 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.

3. Resistance form of a Post
a) Stress distribution
The greatest stress distribution is at the shoulder, particularly interproximally, Dentin
should be conserved in these areas.
Parallel sided posts may distribute stress more evenly than tapered posts.
Sharp angles should be avoided.
High stresses are generated during insertion, particularly with smooth, parallel
sided posts that have no vent for cement escape.
Threaded posts distribute stresses more evenly if the posts are backed off half a

b) Rotational thickness
post with a circular cross section should not rotate during
function.
Pins
Pins are used either alone or in combination with a post
Retention for the core material
Increase the resistance
Maximum of 3 pins in anterior teeth if no coronal tooth structure
exists

groove
If sufficient coronal structure is present rotation is
prevented by a vertical coronal wall.
If coronal dentin is absent then a small vertical groove
in the canal serves as an anti rotational element.
Located in the bulkiest area of the root, usually lingual

•Prefabricated cemented post
•Prefabricated threaded post
•Custom cast post and core
•Glass fibre snow post
Techniques in post space
preparation

Acc. to Rosenstiel
Removal of the
root canal filling
material to the
appropriate depth.
Enlargement of
the Canal.
Preparation of the
coronal tooth
structure.

Acc to Ingle
Coronal tooth
preparation
Root canal
preparation
Pulp
chamber
preparation

Coronal tooth preparation
 Amount of tooth structure that needs to be
removed-
type of crown to be placed
extent of core fabrication
 Thin tooth structure- remove that part of dentine

Pulp chamber preparation
 Cleaned of any filling material
 If prefabricated post- undercuts and irregularities
aid in retention of core material
 If custom cast post- undercuts should be
eliminated

Root canal preparation
 Prudent to isolate tooth with a rubber dam
 Periodontal probe- measure preparation depth
The root canal should be completely obturated in the
first place so as the lateral canals get sealed.
Full length silver point- removed and the canal should
be retreated with gutta percha.

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

Methods to remove Gutta Percha
 Use of heated hand pluggers
 Use of Chemical solvents
 Use of rotary instruments

Use of heated hand pluggers
A heated instrument such as a lateral compactor can be inserted
in to the canal up to desired depth.
In narrow canals system B spreader is ideal for removal.
The hot instrument is carried in to canal and allowed to cool in the
canal for up to 7-10 seconds

Use of Chemical Solvents
Organic solvents such as Chloroform , Eucalyptol or Xylol
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
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. www.indiandentalacademy.com

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

Prefabricated cemented/bonded
post

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.

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

Prefabricated threaded post

Custom cast post and core
Direct method

Direct method for multirooted teeth

Indirect method

Indirect method for multirooted teeth

Glass fibre snow post system

Root reinforcing post
Composite resin reinforce internal walls of roots
thinned by caries
Composite Injected into primed and bonded dentine
canal,
light transmitting post used to shape and set
composite
Post removed , metal post of same dimension
cemented www.indiandentalacademy.com

Temporization

Cementation
 Zinc phosphate cement
 Polycarboxylate cement
 Glass ionomer cement
 Resin Composite cements
 Resin modified Glass Ionomer
Once mixed, the cement is delivered to the dowel space with a
lentulo spiral, to ensure that all walls are coated.
At the same time, the dowel and core are coated with a thin
layer of cement.
The restoration should slide slowly and easily into place with
light finger pressure.
Excess cement must escape coronally as the dowel nearly fills
the dowel space. www.indiandentalacademy.com

Core fabrication
restorative material placed in the coronal area of tooth.
This material replaces carious, fractured or otherwise
missing coronal structure and retains final coronal
restoration
anchored to the tooth by extending into the coronal
aspect of the canal or through the endodontic dowel
Pins, grooves can be placed in dentin in a position
remote from dowel space & keways help to provide
anitirotational stabilitywww.indiandentalacademy.com

Desirable physical properties
 High compressive strength
 Dimensional stability
 Ease of manipulation
 Short setting time
 An ability to bond to dowel & tooth

Optimal core build up materials
Cast metal Amalgam
Composite Glass Ionomer

(1) Cast Metal
A cast dowel and core are a traditional & proven method to restore
endodonticaly treated tooth.
cast core does not depend on mechanical means for retention to dowel.
This construction avoids dislodgement of core & crown from dowel &
root when minimal tooth structure remains.
Disadvantage :
 Cost is high
 Two appointments are needed
 Laboratory phase may be technique sensitive
 Casting large core with small dowel can result in porosity at dowel core
interface

(2) Amalgam core:
It is strong, economic, easy to use, very stable to thermal, functional
stresses, high compressive and tensile strength and high modoulus of
elasticity.
Amalgam cores are highly retentive when used with a preformed dowel in
posterior teeth .
Disadvantage :
 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.

(3) Composite resin core
Easy to build up and sets very rapidly.
Preparation for final restoration is readily accompanied
during core placement session.
Auxillary pins and dentin bonding agents are used for
auxillary retention.
 Polymerization shrinkage and contraction away from tooth
structure can result in core or tooth marginal openings,
microcracks and microleakage.
More than 2mm sound tooth structure should remain at
margin and dentin walls should be present for optimal
composite core function.www.indiandentalacademy.com

(4) Glass Ionomer core
High viscosity glass ionomer employ adhesion to dentin. This chemical
union improves retention of restoration and reduces marginal leakage
over that of unbonded amalgam, and composite resin cores.
The anticariogenic effect derived from presence of flouride
Disadvantages
 GIC cores are sensitive to moisture.
 GIC cores have low strength
 Brittle because of low fracture toughness.
Indicated in posterior teeth where bulk of core is possible significant sound
dentin remains moisture control is assured. Resin moidfied GIC

Coronal radicular restoration
Nayyar technique (1980) Coronal-Radicular
restoration.
Amalgam core build up, where retention is gained from
pulp chamber and coronal part (2-4mm) of root canals.
As posts and pins are not used, perforations and
cracking are unlikely.
Bonding of core by Panavia or other 4-META containing
agents and in retention and decrease coronal leakage
Composite core in Nayyar technique- pulpal floor is
sealed with resin modified glass ionomer, as composite
is difficult to remove, should the root canals be

Endodontically treated teeth
serving as abutments

Factors considered
 Use of post or no post
 Type of post anticipated based on root anatomy
 Methods of post placement and cementation
 Distribution of forces on the abutment teeth
 Use of ferrule effect
 Status and soundness of coronal margins on
sound tooth structure

Overdenture abutment
preparation
 Crowns amputated 3 to 4 mm above the gingival level.
 The coronal 3 to 5 mm of the gutta-percha filling are
then removed, the preparation is undercut, and a well-
condensed amalgam filling is placed to cap the canal
obturation.
 The abutments should rise 2 to 3 mm above the tissue
and rounded or bullet shaped with a slope back from
the labial surface to accommodate the denture tooth to
be set above it. They should then be highly polished .www.indiandentalacademy.com

Removal of existing posts
for retreatment of a failed root canal filling.
risky process- radicular fracture.
If sufficient length of post is exposed coronally, the
post can be retrieved with thin-beaked forceps.
Vibrating the post firstwith an ultrasonic sealer will
weaken brittle cement and facilitate removal.
A thin sealer tip or special post removal tip iswww.indiandentalacademy.com

Masserann technique
An embedded fractured post- Masserann in 1966
Use special hollow end-cutting tubes (or trephines)
to prepare a thin trench around the post
Retrieval can be facilitated by using an adhesive
to attach a hollow tube extractor or by using a
threaded extractor

Thomas Gonon system for post
removal

A post that has fractured within the root canal
cannot be removed with a post puller or forceps.
The post can be drilled out, but great care is needed
to avoid perforation.
The technique is best limited to relatively short
fractured posts.

Failures in post and core
restorations
 Post loosening – 60 to 70% of all failures
 Root fracture
 Post fracture
 Delamination of core from post – loss of crown
retention

Recent advances
Core material – pressed ceramic
Ceramic Posts
Castable glass posts and cores, glass infiltrated
alminous porcelain post and cores produced
conventionaly or machined from computer linked
systems have been developed.

The introduction of zirconium oxide ceramics have
provided a material with over twice the flexure
strength of aluminous ceramic system.
Eg: Cosmo post
It is cylindrically shaped with a conical tip. It is
available in two relatively wide diameters
(1.4mm, 1.7mm).
It is suitable if 1/3 of coronal tooth structure
remains.

Conclusion
A pulpless tooth has commonly lost substantial
tooth structure.
Restoration conserves and protects the remaining
tooth structure
Application of sound biomechanical principles
Long term clinical success - skilled integration of
restorative and endodontic disciplines.

References
• Contemporary fixed prosthodontics- Rosenstiel ,
Land and Fujimoto. 4th edition.
• Fundamentals of fixed prosthodontics-
shillingburg,et al. 3rd edition.
• Endodontics:- Ingle, Bakland, 5th Edition
• Pathways of the pulp :- Cohen S,8th Edition
• Problem solving in endodontics- Gutmann
• IJP 2008 vol 21:4;328-336
• Dental update 2008 35; 222-228

• DCNA 36:3;631-650
• DCNA 45:1;103-116
• DCNA 46:2;367-384
• BDJ 2005 198:8;463-541

Thank you
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