This document discusses the indications, contraindications, and factors affecting the adhesion of post-core systems. It defines posts and cores, their classifications, and their indications and contraindications. Adhesion is defined as the proper adapting or close fitting of post-core systems. Factors that can affect adhesion include the working environment, integrity of root canal dentin, luting agents/adhesives used, and post-core materials and their properties. Proper moisture control, removal of smear layers, and material properties are important for optimal adhesion.

1. INDICATION, CONTRA-INDICATION AND
FACTORS AFFECTING ADHESION OF POST CORE
SYSTEM
PRESENTED BY
DR AGHIMIEN OSARONSE

2. OUTLINE
• INTRODUCTION
• POST....DEFINITION AND CLASSIFICATION
• CORE....DEFINITION AND CLASSIFICATION
• INDICATIONS FOR POST CORE SYSTEM
• CONTRA-INDICATIONS..
GENERAL CONSIDERATION
TOOTH ASSESSMENT
ADHESION OF POST-CORE SYSTEM
DEFINITION OF ADHESION
MECHANISMS OF ADHESION
INTERFACES OF ADHESION

3. OUTLINE COND’T
• FACTORS AFFECTING ADHESION OF POST
CORE SYSTEM
 WORKING ENVIRONMENT
 INTEGRITY OF ROOT CANAL DENTIN
 TYPE OF LUTING OR ADHESIVE USED
 POST CORE MATERIALS AND THIER
PROPERTIES

4. INTRODUCTION
The longevity of a post core system depend
highly on how well they adhere together
whether between the post and core, post and
tooth, core and tooth or between the post-
core and the coronal restoration.

5. POST
Definition;
these are restorative dental materials place in
the root of a structurally damage tooth to provide
adequate retention for the core and coronal
restoration.
when insufficient crown tissue is left on a vital
tooth to accommodate placement of a core (to
support a crown), elective root treatment may be
undertaken to allow for placement of an intra-
radicular post

6. CLASSIFICATION OF POST
Preformed or custom made;
Rigid or non-rigid; Au-Pd and carbon fibres
respectively
Stiff or resilience; rigid post are stiffer
compare to non-rigid posts.
Aesthetic or non aesthetic; ceramics post are
of better aesthetic anteriorly than carbon
fibre[black]

7. CORES
Definition;
these are restorations place in order to build
up a broken down tooth replacing carious,
fracture or missing coronal structures before
the final indirect restoration

8. CLASSIFICATION OF CORE
Base on function;
 Space filler; amalgam, RmGIC, GIC
 Structural; amalgam, GIC, Composite
Base on method of preparation;
 Direct; amalgam, resin composite, GIC
 Indirect; cast metal e.g gold

9. INDICATIONS FOR POST-CORE SYSTEM
A. Amount of tooth structure remaining;
excessive loss from caries, fracture or from
previous restoration weaken tooth and would
not provide enough support for the extra-
coronal restoration.
B. Functional load of the teeth; abutement teeth
for fixed or removable partial denture that is
compromised; teeth that exhibit extensive wear
from bruxism, heavy occlusal load or heavy
lateral function require post, core and crown.

10. 3. Teeth liable to fracture following endodontic
treatment; creation of access and cleaning and
shapening of the tooth during endo treatment further
weaken a tooth hence, the need for a post-core for the
indirect restoration.
4. vital tooth with insufficient coronal tooth that will
support the indirect restoration; these teeth would
require an elective root treatment for the post-core
that will provide the scaffold for the crowning.
5. Anatomic position of teeth; a posterior tooth that
would loss more tooth structure from an endo
treatment compare to an anterior teeth would be
needing a post-core to support the extra-coronal
restoration to help withstand the masticatory stress.

11. CONTRAINDICATIONS FOR POST-CORE
General considerations;
Poorly motivated patients; these patients will
not keep to appointment and probably can
not maintain the restoration.
Poor oral hygiene; it shows a low level concern
about the oral environment. This could
predispose to periodontal disease condition,
thereby compromising the tooth support

12. TOOTH ASSESSMENT
A. Tooth support; bony support restricted to less
than one third of the apical regions is contra-
indicated for a post-core. Tooth extremely
mobile i.e > grade 3
B. Presence of persistent periapical pathosis that
is refuses to subside. If a post-core is place there
could be apical re-infection
C. Poorly root- filled tooth; marginal leakage from
apical aspect could precipitate apical re-
infection

13. ADHESION OF POST-CORE SYSTEM
ADHESION;
this is the proper adapting or close fitting of a post core
system to the root canal space.
MECHANISM OF ADHESION;
chemical e.g silanization
micro-mechanical e.g from phosphoric acid
INTERFACES OF ADHESION
 B/W root canal space and luting/adhesive agent
 B/W post and luting/adhesive agent
 B/W post and core
 B/W core and coronal restoration

14. FACTORS AFFECTING THE ADHESION
OF POST-CORE SYSTEM
1) WORKING ENVIRONMENT;
 moisture control
 saliva and blood contamination;
this could encourage bacterial colonization with
further release of enzyme that would
breakdown the interface.

15. INTEGRITY OF ROOT CANAL DENTIN
Adequate removal of root filling; if this is not
done properly, it could desiccate the canal
surface there reducing the adhesive strength
of the luting agent e.g GIC
Presence of sealing; eugenol have been said to
reduce bonding strength of Zinc phosphate
and decrease polymerisation of resin, ethyl
alcohol and phosphoric acid etching can be
use to remove eugenol residue.

16. Presence of smear layer; in case of further
instrumentation of the canal dentin, the
smear layer if not removed could interfere
with bonding. Acid treatment would do for
this.
A sound dentin integrity is needed for the resin
tag[ especially the minor tags] formation
which would aid chemical bonding to the
mayerials

17. LUTING AGENTS AND ADHESIVES USED
1. ZINC PHOSPHATE; it retention is by mechanical
means only, it doesn’t bond to tooth surface [
hence, sandblasting of the post is advocated]
leaving space for bacterial proliferation which
would eventually cause decementation and
postoperative sensitivity.

18. 2. GIC and RmGIC; it bonds chemically, its
setting is moisture sensitive causing to expand.
This does favour metallic post but causes all-
ceramics to fracture. Adhesion can be improve
when polyacrylic acid or phosphoric acid is used
to pre-treat the preparation to remove smear
layer

19. • Adhesive cement; this tend to give better
adhesion to the post and canal surface with
greater resistance to debonding. Self cure,
chemical and the dual cure can be used. The
dual cure has the advantage of command set,
with the need of extending the length of the
post for retention.

20. POST CORE MATERIALS AND THIER
PROPERTIES
 Materials range from cast gold to fibre[ carbon, quartz,
glass] , to ceramic, and to fibre re-inforce composite[FRC]
post.
 SURFACE FINISHING; metal post-core system could be
smooth or rough. Adhesion of these post can be improve
by sandblasting or micro-abrasion.
 chemical constituent; e.g FRC post can be pre treated with
silanization alone or with potassiun permanganate, sodium
ethoxide e.t.c
porcelain post can be pre-treated with hydrofluoric acid and
ammonium bifluoride for ceramics.
These mtds allow for both chemical and micro-mechanical
adhesion.

21. Other considerations
1. Amount of functional load applied on the
tooth and the restoration
2. Effect of repeated thermocycling

22. conclusion
It is obvious the post core system adhesion is an
important factor to consider when embarking
on such treatment procedure to ensure
longevity of the treatment.

23. GOOD MORNING.