The document discusses the significance of a double seal in endodontics to prevent micro leakage during root canal treatment, emphasizing various materials like gutta percha, amalgam, and zinc oxide eugenol for coronal sealing. It reviews multiple studies that compare the sealing efficacy of different temporary restorative materials and highlights the challenges in achieving a perfect seal due to the nature of dental materials and tooth anatomy. Ultimately, it concludes that while various materials are tested, their effectiveness can vary greatly, making certain combinations preferable for optimal sealing.

2. Presenter: Dr.Epsita Ghosh,PGT
Moderator:Dr. A C Bhuyan,HOD
Department of Endodontics & Conservative Dentistry.
Regional Dental College,Guwahati

3. Contents:
Introduction
Definition
Review of the articles
Purpose of double seal
Material used for coronal sealing
Combination of material used
Results of different combinations
Conclusion
References

4. Introduction
The ultimate goal of root canal therapy is to conquer the complex root
canal system by perfect obturation. Even after a three dimensional obturation
of the system, coronal restoration may fail to provide a perfect seal and may
permit microorganism & their toxins along the canal walls to their periapical
tissue, leading to the failure of the treatment. So the quality of the coronal seal
should be adequate to prevent micro leakage in to the canal space.Thus the
concept of double seal came .

5. Lack of satisfactory temporary restoration during
endodontic therapy ranked second amongst the
contributing factors in continuing pain after
commencement of treatment.

6. A DOUBLE seal consisting of gutta percha underneath material such as temporary
cement ; used to close the coronal opening in a tooth during endodontic treatment.
Seal is defined as something that blocks entry into or out of a container or other
objects. Hence it is a difficult term to justify or use clinically since complete sealing
is impossible with current available dental materials and due to the porous
structure of the tooth itself.

7. •Many materials can be used to achieve some of these goals for effective inter-
appointment temporization. It is essential to have adequate knowledge of temporization
techniques and material properties in order to satisfy a wide variety of clinical
requirements such as time , occlusal load and wear ,complexity of access and absence
of tooth structure.
 Coronal 3-4 mm should be left for the placement of this double seal.
 Numerous factors may effect coronal leakage in root canal treatment including
 The oral flora
 The root canal sealer
 The smear layer
 Coronal restoration

8. •Sommer,Ostrander and Crowley state that the pulp chamber opening
should be sealed by applying a softened layer of gutta-percha over the dressing ,
with a space of 1.5 mm alllowed for the final cements.
• Stewart ,mention that a double seal is generally employed to prevent
medication from escaping from the tooth.The inner seal generally consist of
Gutta percha and an outer seal of “some cement substance is then placed.’’
•Grossman in discussing the selection of a temporary filling material, states
that zinc oxide –eugenol cements are probably best and that gutta percha
preparations, intermediate and zinc phosphate cements are the worst. He
recommends the use of zinc phosphate cement over gutta percha to seal
posterior teeth and zinc oxide eugenol over gutta percha over anterior teeth.
Related studies:

9. • Fischer made a careful study of the zinc phosphate cement and other
permanent filling materials. He found that under the conditions of testing used
in his study, every filling material tested showed some degree of fluid
penetration at the margin.
• Massler and Ostrovasky ,and Weiss tested the relative sealing properties
of a number of commonly used filling materials. The results of these two studies
confirmed the reports of previous investigators, that is that the commonly used
filling materials exhibit marginal leakage in a short period of time and that ,at
room temperature, zinc oxide eugenol cement and amalgam are most effective
sealing agent

10. .
• Saunders and saunders (1990)study indicated that pulp chambers
restored with glass ionomer ,cermet cement,or amalgam leaked significantly
less than those filled with gutta percha and root canal sealer.
•Magura et al(1991) suggested that when temporizing the access opening
of an endodontically treated tooth consideration must be given to the material
choosen to fill the voids.Their results suggested that a thickness of IRM greater
than 3 mm should be used or the clinician should use double seal, possibly Cavit
And IRM to ensure the integrity of the root canal.
• Magura et al(1993) evaluated the coronal leakage of human saliva in
endodontically treated teeth.They reported that saliva penetration at 90
days was significantly greater than seen at 2,7,14,28 days.This study
came to conclusion that obturated canal that have been exposed more
than three month should be re-treated.

11. Few studies have tested the sealing ability of temporary restorative materials
in various situations
Pai et al.(1999) found micro leakage at the interface between amalgam
restoration & IRM,
Caviton & a double seal of Caviton & IRM temporary restorations was less than
the leakage of temporary materials & tooth cavity walls
In another in vitro study access cavities were prepared entirely in amalgam
restorations and temporised with CAVIT,CAVIT-G,TERM ,zinc phosphate cement
and observed microleakage
Polycarboxylate cement, glass ionomer cement, apart from zinc phosphate &
polycarboxylate cement all the tested material provided a leak proof seal
It has also been demonstrated that access cavity prepared with composite resin
& temporised with ZOE or cavit showed less leakage when compared with
amalgam was used in place of composite.

12. Over the years various materials referred to as ‗Intra-orifice
barriers‘ have been sought by investigators to prevent coronal
micro leakage & help produce a secondary seal for obturated
canal. Thus along with time many sealing material for coronal
sealing was tested.

13. Materials used for coronal sealing are:
• Gutta percha
• Amalgam,
•Intermediate restorative material
•Glass ionomer
•Composites
•Cavit
•Resin bonded cement
•Dental adhesives
•Super-EBA
•TERM
•Coltosol
•White & Grey MTA

14. Gutta percha:
Introducer :Bowman(1867)
Sapodilla Family,Genera Payena
Trans isomer of 1,4-poly isoprene
Two
crystalline
forms
Alpha
1)Direct
form2)Brittle
3)Low melting point
4)Ahesive5)Good
flow
Beta
1)Commercial
form
2)Flexible

15. GUTTA PERCHA : EVOLUTION INTO
DENTISTRY
―GETAH‖- meaning gum
―PERTJA‖- name of the tree in Malay
language
First introduced to dentistry as a temporary
filling material by Edwin Truman.

16. Composition of Gutta Percha
Matrix-Gutta Percha 20%
Filler-Zinc oxide 66%
Radiopacifier –heavy metal sulphates 11%
Plasticizer –Waxes and Resin 3%

17. Gutta percha is available in conventional & standardized sizes
.
Conventional sizes include:
•Extrafine
•Fine fine
•Fine
•Medium
•Fine Medium
•Large
•Extra Large
Standerdized size:
•ISO 2% from size nos.15 to 140
•Greater taper Gutta percha like 4 or 6%
•Protaper like F1 ,F2,F3, F4, F5 which is a variable taper
shaping instruments.

18. Type of Cone:
Standardized cones: Corresponds in diameter and taper of root canal shaping instruments
according to ISO sizes. Sizes of gutta percha Ranges from ISO 10 to ISO
140 and taper available in 0.02,0.04,0.06,0.07,0.08 &0.09
Non standardized : The taper is constant but there is no tip diameter. Hence they need
to be customized.Availble in sizes x-fine,fine-fine,medium-fine,fine-
fine –medium,medium,medium-large & large
Accessory cones : Larger taper descriptive size may be used for lateral compaction
Greater taper cones: Cones with 0.04 or 0.06 taper used together with special engine
driven root canal shaping instruments
Compaction cones : Taper corresponds to the taper of fine spreaders
Another classification of Gutta percha

19. Advantages of gutta percha:
Do not shrinke after insertion
Easily Sterilized
Does not encourage bacterial growth
Radio opaque,non-staining
Impervious to moisture
Easy removal
Least toxic and less irritating
Disadvantage of gutta percha:
Lack of rigidity
Lack of length controll

20. Protaper gutta percha
 Recent advances in instrument designs
and materials have resulted in the use of
Ni-Ti rotary and hand PROTAPER
instruments for better shaping and
cleaning of the teeth.
Ni Ti rotary and hand protaper instruments
used to prepare Root canal
in a crown down technique .
Gutta percha cones are now produced to
match the taper of canals prepared
with Protaper hand & rotary instruments.

21. With NiTi protaper rotary preparation of the root canal and use
of a sealer, these cones provides three dimensional obturation
of the root canal over its whole length without the use of
accessory cones or time spent on lateral condensation.
Manufacturers of gutta percha points matching the canal
shapes created by instruments of similar taper claim that they
can fill tapered canal effectively.
Available in boxes of individual sizes,F1, F2, F3 & assortments
of F1 to F3 and F4 to F5
.

22. Protaper next
These unique gutta percha points mirror the progressively tapered designs
of PROTAPER NEXT rotary finishing files for system based efficacy.
Precision machined gutta-percha master cones
No more size irregularities from hand rolling
Consistent sizing between precise and predictable fit
The variable –tapered designs conforms to the file and shaped root canal
Micronized formula helps deliver warm gutta percha 4.5 mm beyond a heat
source
Working temperature of 105-108ºC
Latex free
Available in X2,X3,X4,X5

23. •Gutta percha & temporary stopping gutta percha were among the first material
tested,with less than ideal characteristics.
•Paris et al. found that gutta percha temporary fillings leaked when subjected
to two extreme temperature 4-60 degree.
•Findings from different studies,Kakar & Subramanian said that Gutta percha is
Inferior to ZOE with or with out thermocycling.
•Thus gutta percha is not a commonly used temporary restorative material & not
recommended for this purpose in endodontics.

24. Amalgam
Rhein in 1897 used amalgam to seal the pulp canal after complete root resection.
Initially copper amalgam was used and later silver amalgam was used widely.
a·mal·gam: any alloy of mercury with
another metal or other metals [silver
amalgam is used as a dental filling]†

25. Classification of amalgam alloy:
Based on Copper content:
•Low copper alloys :copper less than 6%
•High copper alloys:copper more than 6%
1. Admixed or dispersed or blended alloys
2. Single composition or unicomposition alloys
Based on Zinc Content
• Zinc containing alloys
• Zinc-free alloys
Based on shape of the Alloy Particle
• Lathe cut alloys
• Spherical alloys
• Spheroidal alloy
Based on number of alloyed metals
• Binary alloys,e.g .silver tin
• Ternary alloys,e.g.silver-tin-copper
• Quaternary alloys,e.g.silver-tin-copper-indium
Based on Size of Alloy
• Micro cut
• Macro cut

26. Alloy Powder Composition
Type Ag Sn Cu Zn Other
Low copper 63-72 26-28 2-7 0-2 —
High-Cu admixed
lathe-cut
40-70 26-30 12-30 0-2 —
High-Cu admixed
spherical
40-65 0-30 20-40 0 0-1 Pd
High-Cu unicomp-
ositional spherical
40-60 22-30 13-30 0
0-5 In,
0-1 Pd
compositions in weight percent

27. Amalgam Capsules
 Contain (in separate
compartments):
 powdered amalgam
alloy
 liquid mercury
 Some are manually
activated, others self-
activated
 Pestle usually
included

28. Reaction: Low-Copper Alloys
Ag3Sn() + Hg 
Ag2Hg3(1) + Sn7-8Hg(2) + Ag3Sn()

29. Reaction: High-Copper Alloys
Ag3Sn() + Ag-Cu + Hg 
Ag2Hg3(1) + Sn7-8Hg(2) + Ag3Sn() + Ag-Cu
and
Sn7-8Hg(2) + Ag-Cu 
Cu6Sn5() + Ag2Hg3(1)

30. Properties of Mercury
 Only liquid metal at room temperature
 Evaporation rate
 Theoretical maximum is 57.9 µg·cm2·s–1 from pristine,
oxide-free surface into a vacuum (= 57,900 ng·cm2·s–1)
 Measured rate in vacuum is ~40 µg·cm2·s–1 (= ~40,000
ng·cm2·s–1)
 Oxidation of Hg lowers rate by factor of 1000

31. Mercury Dose from Amalgam
 Person with average number of fillings (7) would
absorb ~1.6 µg/day
 Person with a moderately high number of fillings (13)
would absorb ~3 µg/day
 Absorbed dose of mercury from food, water, and air is
5.7 µg/day

32. Disadvantages:
•The placement of amalgam as restorative of choice in
which has metallic post or crown for restoration could
create galvanic couple and generate significant amount
of galvanic current.
• Sufficient depth must be provided to place base
material such as calcium hydroxide or zinc oxide
eugenol to prevent galvanism.
•Amalgam may be scattered in the perforated area and
may cause staining.

33. Zinc phosphate cement:
• Studies regarding the sealing ability of the zinc phosphate cement is controversial.
In an in vivo study by Krakow et al.1977 said that no leakage was found in
maximum cases.
•In another study using the fluid filtration method to test microleakage,
Zinc phosphate did not show significant microleakage
•Bobotis et al.1989 found visible micro leakage after temporisation with ZnPO4
cement.
•It was found that zinc phosphate cement was inferior to zinc oxide/calcium
sulphate based material when compared to the property of condensed amalgam
and ZOE.
•Thus Zinc phosphate cement is not widely used for endodontic temporisation
in combination with any other sealing material.

34. Polycarboxylate cement:
•This material has been tested as a temporary restoration in vitro studies with
conflicting result.
•Marosky et al.(1977) found polycarboxylate cement to provide least desirable
seal when compared to Temp seal,Cavit,ZOE,zinc phosphate cement and IRM.
•Polycarboxylate cement is not commonly used in endodontics as its clinical
effectiveness is not well established

35. Zinc oxide eugenol
PCS regular & Extended Working Time PCS EWT
Powder:
Zinc Oxide 34-41.2%
Precipatated silver 25-30%
Oleo resins 30-16%
Thymol iodide 11-12%
Liquid:
Oil cloves 78-80%
Canada Balsam 20-22%
Advantage:
• Excellent lubricating property
•More working time
•Germicidal
•Greater bulk
Disadvantage
•Staining ability
•Rapid setting in high heating
• Type IV zinc oxide eugenol cements are used for intermediate restoration

36. Zinc oxide eugenol
Advantage Disadvantage
 Ease of manipulation
 Plasticity
 Radio opaque
 Germicidal
 Minimal staining
 Accepted working time
 Low setting time
 Good sealing
 Irritation
 Not easily absorbed from
periapical tissue
 Zinc eugenolate is
weak & unstable material
 Has staining property due to
silver content

37.  Liquid/Powder
• Mixed on an oil-resistant paper pad.
• Mixing time ranges from 30 to 60 seconds.
• Setting time in the mouth ranges from 3 to 5 minutes.
 Paste
• Supplied as a two-paste system as temporary cement.
• Pastes are dispensed in equal lengths on a paper pad
and mixed.
Zinc oxide eugenol is supplied as:

38. Many temporary restoration products are ZOE based with or without
reinforcement.
Plain ZOE with a powder to liquid of 4:1g/ml as commonly used results in a
poor initial seal.
A lower water W/P ration of 2:1 gives better initial seal ability but seal slightly
deteriorate with time(Pashley et al.)
Simple ZOE temporary cement was found less effective in precluding radio-activ
tracer leakage when compared to cavit & temp seal , but superior to
zinc phosphate cement ,IRM & polycarboxylate cement.(Maroksy et al.1977)
After thermocycling,Dentemp(commercial name of ZOE ) ,is less effective
in preventing silver nitrate penetration when compared to TERM & three different
cavit preparation., But almost equally effective when compared to IRM
Properties of ZOE based cements:

39. Influence on final restoration
•Material used for provisional restorations in endodontics can affect the polymerisation
& adhesion obtained with composite resins & other materials used to restore
endodontically treated tooth.
•Residual eugenol may have a deleterious effect on physical properties of composite
•Residual eugenol may effect the bond strength of composite
•Incidence & extent of marginal leakage when temporised with Zinc oxide eugenol
•Thus not very effective in Double seal technique

40. IRM(Intermediate restorative material)
Dentsply International,Caulk Division,USA
Temporary filling material in powder and liquid form.
•It’s a ZOE cement reinforced with polymethyl methacrylate.
•This reinforcement provides the restoration with improved
compressive strength, abrasion resistance & hardness(Blanley et al
1981,Anderson et al.1990)
•It provides more optimal physical properties.
•A softer mix of IRM provides better sealing ability due to hydrolysis and
release of eugenol.
•Leakage of IRM increased when subjected to thermal stress.
•Other in vitro studies using radio isotopes & electrochemical method
showed more favourable results with IRM when compared to cavit .

41. Powder contains
75% zinc oxide
20% polymethacrylate
Liquid contains
greater than 99% eugenol
less than 1% acetic acid.
.
Composition:

42. Coming to conclusion from different studies ,It can be stated that ZOE
temporary restorative material including IRM ,can provide adequate
resistance to bacterial penetration during the course of endodontic treatment
especially when used with low P/L ratio. It seals better than amalgam and it
is not affected by root end conditioning agents. It has good tissue
tolerance.It does not have any hard tissue forming capacity.

43. Glass ionomer
Glass ionomer has variety of application in the field of endodontics(Friedman 1990)
It consists of poly acrylic acid and a glass
powder such as alumino silicate.
Glass ionomer cements can be either
light or chemical cure.
Seal and marginal adaptation of the light
cure is superior to the chemical cure.
Seal is better than amalgam and similar
to that of IRM.
 Glass ionomer cements are susceptible
to attack by moisture during initial setting

44. Composition:
Powder:
Silica -41.9
Alumina-28.6
Aluminium flouride-1.6
Calcium flouride-15.7
Sodium flouride-9.3
Aluminium phosphate-3.8
Radio-opacifier
Liquid:
Polyacrylic acid
Tartaric acid
Water

45. Types of Glass Ionomer
Type I
• For the cementation of metal restorations and direct-bonded orthodontic
brackets.
Type II
• Designed for restoring areas of erosion near the gingiva.
Type III
• Used as liners and dentin bonding agents.
Type IV
Fissure sealants
Type V
Orthodontic cements
Type VI
Core build up

46. Benefits of Glass Ionomer:
 Powder is an acid-soluble calcium. The slow release of fluoride from this
powder aids in inhibiting recurrent decay.
 Causes less trauma or shock to the pulp than many other types of cements.
 Low solubility in the mouth.
 Adheres to a slightly moist tooth surface.
 Has a very thin film thickness, which is excellent for seating ease.

47. Supply of Glass Ionomer:
 Powder/liquid
• Mixed manually on a paper pad or
a cool, dry glass slab.
• Glass slab increases the working
time of the cement.
 Premeasured capsules
• Triturated and expressed through
a dispenser.

48. Glass-ionomer alone or on top of an IRM base provided a significantly
superior seal against penetration of S.mutans when compared to cavit,
IRM and glass-ionomer on a cavit base
The adhesion mechanism of glass-ionomer cements explains their acceptable
sealing ability.(Watson 1999)
Moreover glass-ionomer cement posses excellent antibacterial property
against bacterial strains(Tobias et al ,1985)
The antibacterial activity of the material is attributed to the release of fluoride
,low Ph, and /or the presence of certain cations,such as strontium & zinc.

49. • Mineral trioxide aggregate is a new biocompatible material
with numerous exciting clinical application in endodontics.
• MTA was introduced by Torabinejad et Al at Loma Linda
university in 1993 as a root-end filling material and for repair
of lateral perforation .
• It has been patented and has received approval of FDA and is
commercially available as Pro-Root MTA by Dentsply
International .
• Several in vitro and in vivo studies have shown that MTA
prevents microleakage, is biocompatible and promotes
regeneration of original tissues when placed in contact with
periradicular tissues or dental pulp.
Mineral trioxide aggregate

50. MTA (Mineral Trioxide Aggregate)
Scanning electron microscopic analysis indicated that cementoblasts
could reattach and grow on MTA. In addition strong expression of
osteocalcin gene was seen after application of MTA. MTA also
increases the production of both proinflammatory and anti
inflammatory cytokines from osteoblasts
ProRoot MTA(Dentsply)
Mineral Trioxide Aggregate
Composition
Available in White & Grey color
Grey color contains---
Tricalcium silicate
Dicalcium silicate
Bismuth oxide
Calcium sulphate
Tetracalcium aluminoferrite
White color MTA contains same composition as grey color
MTA except
Lack of tetra calcium alumino-ferrite

51. •MTA has longest setting time of 2 hours and 45 minutes.
•Compressive strength is lowest at 24 hours-40 MPa, but it increases to
67MPa , 21 days after mixing.
•The compressive strength, radiopacity and the solubility of MTA are as
those of amalgam, super EBA and IRM.
• But it is more radiopaque than IRM and super EBA. Initially pH is of 10.2,
which rises to 2.5, three hours after mixing;
•pH is about 9.5 at 168 hours after mixing.
• Mean particle size is 10µm.Range of particle size is from 0.1 µm to 100
µm.
•Holland et al theorized that the tricalcium oxide in MTA reacts with tissue
fluid to form calcium hydroxide resulting in hard tissue formation.
•Studies in dogs have reported with less peri-radicular inflammation and
cementum deposition immediately adjacent to the material.
Properties:

52. continuation.....
Has biological properties like calcium
hydroxide
High compressive strength
Produce high setting non resorbable surface
Hydrophilic nature
Low solubility, resist to marginal leakage
Biocompatible
Non sticky
Bacteriostatic
Disadvantages:
Difficult to manipulate
Long setting time
Costly

53. Management
Pro root (commercial name of MTA) is mixed with anaesthetic solution or
sterile water to a heavy, cake like consistency.
A small amount of the material is picked and introduced into the canal
with a micro-tube carrying device, such as customized spinal tap needle or
on the side of West perforation repair instrument.
Pro root is then tamped and coaxed down the canal to approximate
length using a customized nonstandard gutta percha cone as a flexible
plugger.

54. SETTING REACTION
• On addition of water compound in MTA react to produce calcium
silicate hydrate gel that is calcium hydroxide contained in a
silicate matrix.
• The dissolution of anhydrous phase of MTA occurs followed by
the crystallization of the hydrate in a interlocking mass which
consists of cubic and needle like crystal.
• In the crystal kinetics point of view the complexity of MTA
resulted in different nucleation rates and some parts move
rapidly than others to construct the epitaxillary growth.
• According to patent of MTA C3S is a predominant phase and play
an important role in its hydration behaviour.

55. • The hydration of C3S is follows chemical process and
produces calcium silicate hydrate and calcium hydroxide.
The set MTA exhibits both crystalline and amorphous phases.
• The crystalline material is essentially calcium oxide and
amorphous phase is calcium phosphate.
• MTA consists of hydrophilic particles and sets in presence of
moisture.
• In clinical setting a moist cotton pellet need to be placed
over MTA to help in setting reaction.

56. 2. USAGE TECHNIQUE
To prepare medium size portion: one measure of MTA powder + 01 drop of distilled water.
a- Put one measure of powder and one drop of distilled water upon a
sterilized glass plate;
b- Spatulate both for 30 seconds until the perfect homogeneity of the
components. The cement got must have a sandy consistency, similar to
amalgam, but more humid;
c- Insert the spatulated cement in the place desired, using a sterilized
amalgam-place or another professional instrument of your preference;
d- Condensate the material inside the dental cavity.

57. Studies on adaptation/microleakage
• Fluid transport models comparing microleakage of MTA and
amalgam or EBA, amalgam and MTA showed less microleakage
with MTA (Yasshushiri et al )
• Torabinejad et Al evaluated marginal adaptation using SEM
revealed that MTA had better adaptation than other material.
• Endotoxin studies by Torabinejad et Al also confirms superior
sealing ability of MTA using E.Faecalis to test sealing property.

58. •Study by Lawley et Al using PCR followed by
reverse blot confirms superior sealing and
adaptation of MTA.
•Schress found that MTA did not allow
passage of strict anaerobes for duration of
47 days. MTA also gives seal against
S.Epidermidis,F.nucleatum,S.Marcesences

59. Mechanism:
 MTA’ s sealing ability and better marginal
adaptation is probably due to its hydrophilic nature,
longer setting time and slight expansion when it is
cured in moist environment.
 MTA contains 5% gypsum that expands during
setting contributing to better adaptation .

60. Studies:
 Investigation of why MTA appears to induce
cementogenesis found that material seemed to
offer a biologically active substrate for osteoblasts,
allowing good adherence of the bone cells to the
material while also stimulating production of
cytokines.
 Koh et Al found that MTA causes an increase in
production of interleukin IL-1α, IL-1β, IL-6 and
osteocalcin.
 Osteocalcin is an abundant protein and may be an
indicator or bone matrix production.
 Mitchell et Al found that set MTA induced
production of IL-6, IL-8, and macrophage colony
stimulating factor

61.  IL-8 promotes the development of new blood
vessels and activate precursor of osteoblasts.
 Macrophage stimulating factor may have a
significant function in osteoclast development and
maturation.
 The source or origin of new cementum is not
clearly understood, Two possibilities exists, one
derived form remaining PDL or one from growing
connective tissue from bone.

62.  White MTA in concentration of 50 mg/ml may
exert an antifungal effect against C.albicans a
period of up to 30 days.
 Recently it has been suggested to mix
chlorhexidine to MTA to enhance its
antibacterial properties ,however its not clear
what effect chlorhexidine has on physical and
chemical properties of MTA.

63. Although EBA, ZOE, and MTA are ineffective against a number
of bacteria MTA is superior to others due to its sealing ability
preventing migration of bacteria and some antibacterial
activity against facultative anaerobes.

64. ROOT-END FILLING:
 Numerous materials have been used as a root-end filling
material. The main disadvantage include their inability to
prevent egress of irritants from infected root canal into peri
radicular tissues, lack of biocompatibility, and their inability to
promote regeneration of peri radicular tissues to their
preassessed status and normalcy.
 MTA is superior to other material as it provides “DOUBLE
SEAL” that is physical seal due to its excellent sealing
property and biological seal due to regeneration of cementum
over it.

65. Precaution for MTA use:
a. MTA –material should be kept in closed container to avoid moisture
b. Material should be immediately placed after mixing to avoid
dehydration during setting
c. Working time is 5 minutes,if more working time is needed then
It should be covered by moist gauge or add a small drop of water during
capillary condensation technique
USE:
 As pulp capping material
 Perforation repair agent
 Root end filling material as apical barrier
 As a paste filling material for obturation

66. •MTA as a double seal in combination with GIC &/or IRM is significantly
better than any other combination.
•Thus MTA with a combination of GIC and / or IRM can be recommended as
coronal sealing material to prevent microleakge in an endodontically treated tooth.
•MTA without secondary seal leak significantly.
www.endoexperience.com/documents/Endotemps.pdf

67. TERM
(composite resin)
Temporary restorative materials for endodontics
This material is a single component light curable resin
Contains:
•Urathane dimethacrylate polymer-matrix/binder
•Inorganic radio opaque filler
•Organic prepolymerised filler
•Coupling agent-organo silanes
•Hydroquinone-inhibit to prevent premature polymerisation
•Opacifier-titanium Di-oxide & aluminium oxide
•UV absorbers-for color stability
•Pigments
•Initiators

68. Properties:
Undergoes polymerisation shrinkage 2.5% of its volume
Has higher hardness ,tensile strength & compressive
strength in comparison to cavit
Sealing ability is effected by intra-canal medicaments
Thermocycling causes increased micro-leakage
Inferior to IRM & Cavit in the context of physical properties
but marginal sealing ability is better
Dye penetration is more after thermocycling when
compared to Cavit

69. Properties:
Undergoes polymerisation shrinkage
Contraction is followed by expansion owing to secondary water
sorption
Minimum thickness for effective cavity sealing was investigated
in vitro using thermocycling and fluid filtration technique...it was
found that 1-3 mm thick TERM is effective for cavity sealing.
TERM has higher hardness,tensile & compressive than Cavit.
Sealing ability is not effected by intra canal medicament(Rutledge
& Montgomery 1990)
Continued...
Uranga et al.(1999) found that composite resin & resin modified
glass ionomer cement provided a better seal against methylene
blue than TERM

70. TERM Can be used in combination with GIC in double seal technique.
But due to polymerisation shrinkage of TERM micro leakage is observed.
Thus not very effective. But the result is controversial

71. (Cavit)
It’s a premixed temporary filling material
Composition:
Zinc oxide
Calcium sulphate
Zinc sulphate
Glycol acetate
Polyvenyl acetate resins
Polyvinyl chloride acetate
Triethanol amine
Pigments
Properties:
•Cavit posses high co efficient of linear expansion resulting from water sorption
•Hygroscopic in nature
•Excellent marginal sealing ability
•Compressive strength is half of the ZOE.
•Properties are not effected by intracanal medicaments
•More effective than TERM & IRM
Zinc oxide/calcium sulphate preparation

72. Types of Cavit
A. Cavit
B. Cavit -G
C. Cavit-W
D. Cavidentin( calcium sulphate based addition of potassium
aluminium sulphide as catalyst,thymol as antiseptic)
 Differ in their content of resin & their resulting hardness & setting.
 The hardness and dimensional stability of cavit,cavit –w,cavit-G decrease
respectively
 Provides equal water tight seal
 Cavidentin &Cavit G were almost equally effective
Cavit

73. Advantages:
 Easy manipulation
 Premixed
 Adequate seal
Disadvantages:
 Less hardness
 Less wear resistance
 Slow setting
 Deterioration with time
Continution...

74. ).
• In in vivo studies, no leakage or minor leakage was found in 27 out
of 32 cases when Cavit was used to temporize access cavities in
anterior teeth and only15% of cases tested showed gross leakage. In
another study,
• Cavit in a 4 mm thickness provided the best seal over a 3 week
temporization period when compared to IRM and TERM (Beach et
al. 1996).

75. A double seal using cavit as an inner layer and IRM as an outer layer
has been recommended to compensate for the undesirable physical
properties of cavit .Furthermore this combination showed better dentine
adaptation when compared to IRM alone(Pal et al.1999)

76. CALCIUM HYDROXIDE CEMENT
It’s a rigid self limiting ,radio opaque calcium hydroxide composition.
Due to their alkaline nature they also serve as a protective barrier
against irritants from certain restoration.Recently ,a light cured
calcium hydroxide base material and a calcium hydroxide root canal
sealing paste have been introduced.
Application:
•For direct & indirect pulp capping
•As low strength bases beneath silicate & composite restoration for pulp
protection
•Apexification
Commercial names:
• .Self cured –Dycal ,Life ,Care,Calcidor
• Light cured-Plasma VLC dycal

77. Available as
Two paste system ,base &
catalyst
Light cured system
Single paste in syringe
Powder form(mixed in distilled
water)
Composition:
Base paste:
1,3 Butylene glycol disalicylate
Zinc oxide
Calcium phosphate
Calcium tungstate Iron
Oxide pigments
Catalyst paste:
Calcium hydroxide
N-ethyl-0/p-toluene sulfonamide
Zinc oxide
Titanium Dioxide
Iron oxide pigments

78. Properties:
Poor mechanical properties
Low compressive strength(10-27MPa after 24 hours)
Low tensile strength(1.0 Mpa)
Low modulus of elasticity
Thermal insulation is possible when used in 0.5 mm in
thickness
The cement is alkaline in nature,
High alkalinity & its consequent antibacterial & protein
lysing effect helps formation of reparative dentin

79. Coltosol
(Colten Whaledent,Mahwah,NJ,USA)
Composition:
•Zinc oxide
•Zinc sulphate
•Calcium sulphate hemihydrate
PROPERTIES:
•Coltosol hardens within 20-30 min.when in contact with moisture
•It is designed for the short term temporisation not exceeding 2 weeks
•Not very effective for endodontic field

80. Materials that can be used in combination in as DOUBLE SEAL are:
Glass ionomer Type II over gutta percha followed by light cure composite resin
as the final seal
Mineral trioxide aggregate over gutta percha followed by Glass ionomer type II
as the final seal
Dycal over gutta percha followed by Glass ionomer Type II as the final seal
Mineral trioxide aggregate over gutta percha followed by intermediate
restorative material as the final seal

81. Combination of GIC & composite is a---
Well documented combination of restorative materials
Can be used for both anterior and posterior teeth
This laminate or “sandwich technique “ has been suggested primarily
for decreasing micro leakage
The combined glass ionomer & composite restoration provides a reliable
chemical bond to dentin
Micromechanical bonding of the composite to ionomer surface and an
acceptable esthetic result
But polymerisation shrinkage of composite may lead to micro leakage

82. The imperfect sealing of the GIC linings might be explained by their
hydrophilic properties,micro gaps and or porosities
.
Initial bond strength to dentin is not strong enough to withstand the
polymerisation shrinkage stress of resin composite.
Moreover GIC absorb considerable amount of fluid while setting
leading to micro leakage

83. MTA with GIC:
•Study was conducted by Hardy et al using MTA for furcation where it was
found that MTA without a secondary seal leaked significantly.
But result is controversial.
• Different studies have that MTA as a Double Sealing Material in combination
with GIC or IRM group can be preferred over the other combination.
• There is no significant difference between the combination of GIC or IRM
along with MTA

84. GIC with Dycal showed
Highest leakage among the combination used
So this combination is not very recommended

85. Methods of evaluation of leakage
 Passive method of dye penetration
 Fluid filtration & trasportation
methodology
Bacteria and toxin infiltration method
 Dye extraction method
3D Computer assisted re-construction

86. Passive method of dye penetration
The phenomenon of capillarity is of utmost importance in this passive method
used mainly for assessing apical leakage, as the tooth apex is submerged in the
dye that penetrates through any space between the canal walls & filling materials
Next ,the teeth are sectioned longitudinally ,transversely ,or cleared and the
linear penetration of the dye is recorded.
Longitudinal sectioning method:
•The longitudinal sectioning method enables examination of the exposed filing
material and at the interface of dentinal wall on one side.
•Ahlberg et al. Suggested a variation of this technique ;where by roots are
worn down to visualize the leakage through a thin layer of dentin, thus reducing
the risk of dye dissolution during sectioning
•They also affirmed that this technique provides more reliable information about
the real leakage pattern than the transverse section or clearing
•The disadvantage is that in longitudinal sectioning the random choice of the
cut axis and the very low probability of the section being made through the
•Deepest dye penetration point, with the consequences of underestimation
& recording of unreliable data.

87. According to Martin et al. and Ahlberg et al transverse root sectioning
results in loss of part of the dentinal tissue & dye due to the technique itself
and only allows one to determine whether or not there is penetration in
each section.
The clearing technique recommended by Okumura in 1927,in which the
teeth become transparent after a process of demineralisation ,dehydration and
immersion in methyl salicylate ,provides a three dimensional view of the internal
anatomy of root canals without the loss of dentinal substance, making it easier to
view the leakage area.

88. Fluid filtration & trasportation methodology:
• The fluid filtration method ,in which the sealing capacity is measured by means
air bubble movement inside a capillary tube, was developed by Pashley’s group
in 1987 & modified by Wu et al.in 1993 for use in root canals.
• It consist of a filled canal that has its coronal portion connected to a tube filled
with water under atmospheric pressure ,and its apex to a 20 micro L glass capillary
tube 170mm long and of uniform calibre filled with water.
•Finally a pressure of 0.1 atm is applied through the coronal part, which forces
the water through the empty spaces along the root canal .
•The results are generally expressed in micro L/min

89. Dye extraction method:
•In the dye extraction method ,the teeth are dissolved in acids that release all
the dye from the interface and the optical density of the solution is measured
by a spectrophotometer.
•It is fast and can be carried out with equipment available at most universities
•According to Camps,Pashley,there was no correlation between dye penetration,
fluid filtration and dye extraction techniques which determine microleakage.
•The fluid filtration gives similar results to those of dye extraction, because both
take in to consideration the porosity of the interface between the filling
material and the root.

90. Bacteria and toxin infiltration method:
•According to Timpawat et al. The use of bacteria to asses leakage is
considered to be of greater clinical and biological relevance than the
dye penetration method.
•Many different strains of bacteria have been used to assess marginal
leakage and has lead to contradictory results, because the method
depends on type of bacteria used.
•More over, if the sealer has antimicrobial property, it is unfeasible to employ
the bacterial method
•The system generally comprise two chambers and enable the apical and
coronal extremities of each specimen to be completely separated.
•The turbidity of the broth in the apical chamber is the first indication
of contamination by micro organism.
•If the pulp chamber becomes contaminated than root canal treatment
may fail .

91. From the various literature ,it is noted that various methodologies are available
for assessing leakage. Some are simple such as dye penetration, and others are
complex, such as bacterial leakage.
It was found that all the methods are really very technique sensitive, thus the
outcome is variable.

92. Rational for Coronal seal:
•It prevents micro leakage
•Without proper seal it takes only 19 days for staphylococcus penetration
•Bacterial endotoxin could damage the total seal
•
•Prevent exchange of fluids between root canal & oral cavity
•Prevents escaping medications from root canal

93. Conclusion

94. Double seal→
•Gives tight seal of the coronal restoration
•Prevents ingress of the micro organism in to the root canal after
commencement of the root canal therapy
•Prevents ingress of the fluids & organic materials from oral cavity to
the root canal
•Prevents seepage of the intracanal medicaments
•Provides acceptable aesthetics
•Protect tooth structure during treatment
•Prevents accidental penetration of permanent filling material inside
the root canal

95. ENDODONTICS: Arnaldo castellucci
PATHWAYS OF THE PULP (6th Edition): Stephen Cohen, Richard C. Burns
PRINCIPLES AND PRACTICE OF ENDODONTICS (3RD EDITION): Walton & Torabinejad
ENDODONTIC THERAPY (6th Edition): Franklin S. Weine
INGLE’S ENDODONTICS 6
GROSSMAN’S ENDODONTIC PRACTICE 12TH Edition
SKINNER’S SCIENCE OF DENTAL MATERIALS:Phillips 9th Edition
STURDEVANT’S ART& SCIENCE OF OPERATIVE DENTISTRY 6th Edition
References: