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PDF, Biocompatability of Endodontic materils , Classification, Uses , biological requirements , Handling-related requirements , Toxicity, Allergy, Mutagenicity
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3/5/2014
1
Subtitle
BIOCOMPATIBILITY OF ENDO-DONTIC MATERIALS
Presented by:
Dr.Hashmat Gul
Demonstrator AMC
Dental Materials
� Clinical success rates of RCT = 70–95%
� Requirements of RCT success
• physical,
• biological,
• handling-related requirements
� Endodontic materials represent only one aspect out of several parameters that are important for the clinical success of an endodontic treatment
Clinical Data and Biocompatibility
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• No systemic toxicity
• Nonallergenic
• Compatible with local (periapical) tissue
• Sterile or sterilizable
• Antimicrobial activity
� ( anaerobes, such as Actinomyces strains and Enterococcus faecalis)
� A complete biomechanical preparation & the entire removal of the invaded microbiota are technically impossible due to
� The complex anatomy.
� Possibility of Deep penetration of bacteria into accessory canals, the apical “canal delta,” and up to 1 mm into the dentin
• Promotion of periapical healing
The Biological Requirements
�Mandibular Nerve Injuries
� CAUSES
• Extended overfilling of RC in lower molar.
• Over instrumentation/over preparation.
Handling Related requirements
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�Rubber Dam
� Should generally be used for each RCT.
� Allergies to latex have been document and allergic reactios to these are mostly type I (immediate) reactions:
1. Localized contact urticaria
2. Anaphylactic shock
� Latex-free rubber dams e.g. based on silicone. One recent case of a type IV reaction to a latex-free rubber dam has been reported
Handling Related requirements
Points Sealer Thermoplastic material
� Gutta-percha points
� Titanium posts
� Silver points
� Zinc oxide eugenol (ZOE)
materials
� Polyketone products
� Epoxy resins
� Calcium hydroxide
based materials
� Mineral trioxide
aggregate(MTA)
� Calcium phosphate
cement
� Silicone based sealers
� Resin based sealers
� Resilon points (resin-
based)
CLASSIFICATION OF ENDO-DONTIC MATERIALS
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Gutta-percha
� Source: Natural product from gutta-percha tree (Isonandra percha).
� Chemically GP is a polymer based on isoprene.
� Types of gutta-percha
� α-GP, which is for injectable techniques
� β-GP, used for points.
� Gamma-GP, not used in Dentistry
� Handling of Gutta-percha
� It is not only used for points but is also applied in a thermoplastic state.
� It is either completely or only superficially heated or liquefied in order to better adapt to the root canal walls.
� Thermoplastic gutta-percha is usually combined with a sealer.
Gutta-percha
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COMPOSITION RELEASE &
DEGRADATION
Systemic toxicity
and allergies
Local toxicity
and tissue
compatibility
Antimicrobial
properties
Mandibular nerve
injuries
� Zinc oxide:
33–61.5%
� Gutta-percha:
19–45%
� Heavy metals:
1.5–31.2%
� Additives( colophony): 1–
4.1%
� Pigments: 1.5–
3.4%
� Zinc ions from
ZnO filler
� CaOH
(additive)
� Nil � No/slight toxic
� Foreign-body
immune
response with
some
products.
� ZnO
� Iodoform :
May cause
toxic/allergic
rxn
� Tetracycline
� Liquefied
gutta-percha
which
extruded from
the root canal
� Overfilling of
gutta-percha
or
chloropercha
can sometimes
cause
parasthesia
Gutta-percha
Fig. A temperature increase of >10°C for more than 1 min may cause bone damage
*cervical area
**central root surface area
***root end,
****with sealer
TEMPERATURE AT THE ROOT SURFACE AFTER APPLICATION OF HEATED INJECTABLE GUTTA-PERCHA
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Zinc Oxide Eugenol Sealer
Type
COMPOSITION
Powder Liquid Additives
� Standard ZnO
Eugenol sealer
� Zinc oxide 42%
� Stabilite 27%
� Bismuth carbonate 15%
� Barium sulfate 15%
� Sodium borate anhydrate 1%
� Eugenol � Thymol/
Thymoliodide
� Hydroxyl apetite
� CaOH
� Modified ZnO
Eugenol sealer
� Zinc oxide 60%
� Aluminum oxide 34% Resins
(e.g., colophony 6%)
� Orthohydroxy-
benzoic acid
62.5%
� Eugenol 37.5%
Zinc Oxide Eugenol Sealer
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RELEASE &
DEGRADATION
Systemic toxicity
and allergies
Local toxicity and
tissue compatibility
Antimicrobial
properties
Mutagenicity &
carcinogenicity
� Colonophony� increase the
adhesiveness
�adjust the speed
of the setting
reaction
�decrease
solubility or
disintegration
� Eugenol
� Formaldehyde/Pa
raformaldehyde
� Eugenol:
�Low Systemic
toxicity
�Impair nerve
conduction
temporarily
� Formaldehyde/Pa
raformaldehyde paste Overfilling:
� Anaphylactic
shock/
Generalized
urticaria
� irreversibly
suppresses the
nerve
conduction
� Hydroxyl apatite or CaOH
� Eugenol:� Contact
allergin
� Highly
cytotoxic
� Formaldehyde:
Contact allergen
Aspergillosis of maxillary sinus
� damage to sinus
mucusa with
formaldehyde+
� ZnO induce
fungal growth.
� Thymol/
Thymoliodide
� Formaldehye
� Eugenol
� FormaldehydeIrreversible
Paraesthesia of
inferior alveolar
nerve.
� Formaldehyde
free ZnO eugenolsealer_reversible
paraesthesia of
maxillary sinus
Zinc Oxide Eugenol Sealer
COMPOSITION RELEASE &
DEGRADATION
Systemic
toxicity &
allergies
Local toxicity & tissue
compatibility
Antimicrobial
properties
Powder� ZnO 97%
� Bi(PO)4 3%
Liquid� Propionylacetophenone
76%
� Vinylcopolymers 23.3%
� Dichlorophene 0.5%
� Tritethanolamine 0.2%
� No data are
available
� Sets by chealation rxn.
� Nil
� Non-toxic after the
material has set.
� Mild peri-apical
inflammation when over-
filled in rat molars.
� Better compatability to
bone when used in thick
consistency.
+++
Polyketone-based Sealers
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Epoxy-based Sealers
TYPES
� AH26,
� with silver
� silver-free.
� AHPlus (also marketed as Top Seal)
RELEASE &
DEGRADATION
Systemic toxicity &
allergies
Local toxicity &
tissue
compatibility
Antimicrob
ial
properties
Mutagenici
ty &
carcinoge
nicity
Mandibular nerve
damage
� AH26-
Formaldehyde
released during
setting only.
� epoxy monomer_
a contact allergen
� Mild/no allergic
erythema of the
face and nape
of the neck
� No systemic toxic
reactions
� Slight cytotoxic
during setting
+++++ � Freshly
mixed_
mutage-
nic.
� Parasthesia_exte
nded over-filling
of mandibular
teeth.
Epoxy-based Sealers
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RELEASE &
DEGRADATION
Systemic toxicity &
allergies
Local toxicity & tissue
compatibility
Antimicro
bial
propertie
s
Mutageni
city &
carcinog
enicity
Mandibular nerve
damage
� -OH and Ca
ions.
� vary from
product to
product.
� No systemic or
allergic reactions
reported so far.
� Low local toxicity occur only in initial
period after
application.
� hard tissue formation at the
root apex
observed.
+
no effect
on E-
faecalis
and
candida
albicans
- - -
� Mandibular
nerve injuries
seldom occur.
Calcium Hydroxide-based Sealers
Calcium Hydroxide-based Sealers
Fig, a-c Healing of a chronic apical inflammation with osteolysis.
a Root canal debridement.
b Application of a calcium hydroxide material.
c Formation of a hard tissue barrier at the root end
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COMPOSITION : A mixture of
� tricalcium silicate
� tricalcium aluminate
� tricalcium oxide
� silicate oxide
TYPES
� white (WMTA)
� grey (GMTA)
� In Grey MTA Al2O3, MgO, and FeO being present in higher concentrations
MIXING & SETTING
The powder is mixed with water, generating a colloidal gel that sets within 3–4 h , followed by a maturation period .
Mineral Trioxide Aggregate
RELEASE &
DEGRADATION
Systemic
toxicity &
allergies
Local toxicity & tissue
compatibility
Antimicro
bial
properties
Mutagenicit
y &
carcinogeni
city
USES
� CaOH � Nil � CaOH� Slightlycytotoxic.
� Cytotoxicity increased
somewhat over time .
� Deposition of new
cementum in open
apex. repairing
furcation perforations.
� Small areas of
ankylosis in lateral
perforations.
+++ - - - � Root canal sealer
� For pulp cappings
� Apexification
� Sealing of
perforations
� Root end filling
Mineral Trioxide Aggregate, MTA
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COMPOSITION
� Tetra-calcium phosphate
� Di-calcium phosphodihydrate/dehydrated dicalciumphosphate
MIXING & SETTING
� mixed with a 1-molar solution of dibasic sodium phospho-heptahydrate
LOCAL EFFECTS
� No inflammation
� Cementogenesis
ANTI-MICROBIAL EFFECT
� Very good , ++++
Calcium Phosphate Cement
TYPES
Systemic toxicity &
allergies
Local toxicity &
tissue compatibility
Antimicrobial
properties
� C-silicones(condensation cross-linking silicones)
� A-silicones (addition cross-linking),
RoekoSeal.
� Gutta-Flow, improved seal by (0.2%)
expansion .
� Silver particles added (preservative).
� Not
documented.
� No/slightly
cytotoxic.
� Non-mutagenic.
� good.
� Little/no
effect on E-
fecalis.
SILICONS
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� Resin based sealers have been introduced to improve the sealing and bonding to root canal dentin.
� These sealers do not adhere to gutta percha so special points have been developed called Resilon .
� It is thermoplastic copolymer of polycaprolactoneand urethane methacrylate.
� These points are bonded to the root canal dentin through a dual curing resin sealer.
RESIN-BASED SEALERS
RELEASE &
DEGRADATION
Systemic toxicity &
allergies
Local toxicity & tissue
compatibility
Antimicrobial
spectrum
Mutagenicity &
carcinogenicity
� Scarce
information.
� Nil � slightly to
moderately
cytotoxic.
� Well tolerated in
periapical tissue.
� not much
broad
� Nil
RESIN-BASED SEALERS
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Fig. Local toxicity of different root canal filling materials in implantation tests.
� Low toxicity (= low toxicity index) of guttapercha
� Decreasing toxicity of an epoxy sealer with increasing aging time
TOXICITY INDEX
MATERIALS FOR RETROGRADE ROOT CANAL FILLING
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REQUIREMENTS
� Excellent sealing capacity
� Stimulation of hard tissue formation
� Stability in a humid environme
USES
� A surgical procedure that is associated with early exposure of a comparatively large surface area to humidity and the presence of a bony defect.
� Where a regular endodontic access cavity is often not possible,e.g. in presence of endodontic post which cant be removed.
MATERIALS FOR RETROGRADE ROOT CANAL FILLING
CLINICAL DATA
�Amalgam and silver points are no longer recommended for retrograde root canal fillings.
� Modified ZOE materials and light-curable glass ionomercements as well as polyketone-based sealers (possibly in combination with preformed inserts) are better alternatives.
� MTA shows very promising results, but more clinical data are necessary. If these data are positive, MTA can be recommended for retrograde fillings.
MATERIALS FOR RETROGRADE ROOT CANAL FILLING
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RETROGRADE ROOT CANAL FILLING
Fig. a,b Treatment after extrusion of a root canal sealer into the mandibular canal.
a Situation after excessive overfilling of a lower left first molar.
b Situation after surgical removal