Biocompatibility of endo dontic materials lecture pdf

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

3/5/2014

2

• 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

3/5/2014

3

�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

3/5/2014

4

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

3/5/2014

5

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

3/5/2014

6

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

3/5/2014

7

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

3/5/2014

8

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

3/5/2014

9

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

3/5/2014

10

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

3/5/2014

11

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

3/5/2014

12

� 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

3/5/2014

13

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

3/5/2014

14

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

3/5/2014

15

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