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1. SEMINAR ON

2. CONTENTS
Introduction
Composition
Types – Gray & White
Mixing time
Setting time
Solubility
Biocompatibility
Radiopacity
pH
Physical Properties
Advantages / Disadvantages
Indications / Contra-Indication
Clinical Applications
• Direct pulp capping
• Apical plug
• Root end filling
• Root perforations
• Furcation involvement
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3. • Resorptive defect
Comparison of Ca(OH)2 & MTA
Neurotoxic Evaluation
Cytotoxic Evaluation
Histologic Evaluation
Cellular Response to MTA
Conclusion
References
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4. INTRODUCTION
Independent analysis suggests that the material of Mineral Trioxide
Aggregate (MTA) is identical to Portland cement. It is a new remarkable
biocompatible material with exciting clinical applications pioneered by
Dr. Mahmoud Torabinejad, Loma Linda University, in 1993. Its first
description in the dental literature in 1993, by Lee & colleagues, that
MTA has been used in both surgical and non – surgical applications,
including root end fillings, direct pulp capping, perforation repairs in
roots or furcations and Apexification. In 1998, MTA’s approval by U.S
Food and Drug Administration led to widespread use. MTA cement
provides a better sealing ability over Amalgam, GIC, IRM, ZOE, and
Super EBA. It’s an ideal material for use against bone for the overgrowth
of cementum, formation of bone and facilitates the regeneration of the
periodontal ligament fibers.
Chemical Composition
(Sarkar et al – JOE 2005)
MTA is a mechanical mixture of 3 powder ingredients:
• Portland cement (75%)
• Bismuth oxide (20%)
4

5. • Gypsum (5%)
Composition includes
• Tricalcium silicate
• Dicalcium silicate
• Tricalcium aluminate
• Tetracalcium aluminoferrite
• Calcium sulfate
• Bismuth oxide
MTA powder consists of fine hydrophilic particles. Tricalcium
silicate, Tricalcium aluminate, Silica oxide and Tricalcium oxide are the
major components and few other mineral oxides are responsible for
chemical and physical properties of MTA. Bismuth oxide added for radio
opacity.
Types of MTA:
There are two types of MTA
Gray and White (Saeed Asgary et al JOE 2005)
5

6. Gray MTA White MTA
FeO - Present FeO – replaced with MgO
FeO (Black) MgO (White)
hue matched the color of teeth
Many of the transitional element (Cr, Mn, Fe, Cu), which have free
d- electrons (electrons not involved in bonding) exhibit strong colors
when in their oxide forms (because these d- electrons can be readily
excited by light in the visible spectrum- that is the solid has a small band
gap). By contrast,
Oxides of the elements that do not have excited electrons (Mg, Al, Si,P,
S, K, Ca, Ti) tend to be colorless or white (large band gap), where as
heavier element Bismuth oxide has a yellow oxide.
Mixing MTA
Prepared immediately before use.
Kept always in closed containers or free from moisture.
Powder: Water = 3: 1
6

7. Glass or paper slab used for mixing with – plastic / metal spatula. It
requires moisture to set. Once the mix is dry sandy form its ready for
application.
Setting Time
MTA powder consists of fine hydrophilic particles. Hydration of
MTA powder results in a colloidal gel that solidifies to a hard structure in
~ 4 hrs which has a long setting time. It is generally considered that a
potential root end filling material should set as soon as placed in root end
cavity without significant shrinkage. This condition would allow the
dimensional stability of the material after placement and less time for an
unset material to be in contact with vital tissues. In general, quicker a
material sets more it shrinks. But MTA has long setting time with less
shrinkage.
Solubility
Lack of solubility is an ideal characteristic of MTA as a root end
filling material. Despite of some advantages of controlled long term
clinical studies, because of its long setting time, the recommended
7

8. methods of ISO (6) or ADAS # 30 (7), the test solubility of MTA had to
be modified.
Biocompatibility
Clinically MTA is a biocompatible material with good sealing
ability should generate little or no inflammatory response in periradicular
tissues, and encourage the formation of fibrous connective tissue and / or
cementum covering the entire root end.
Calcium & Phosphorus are the main ions present in this material,
which are the principle components of dental tissues, hence MTA proved
to be biocompatible when used in contact with cells and tissues.
Radio Opacity
Bismuth oxide added for radio opacity and it is more radio opaque
than its surrounding structures.
Shah et al in 1995 showed that the MTA is less radio opaque than
Kalzinol- (7.97) and more radio opaque than GP (6.14), IRM (5.30),
Super EBA (5.16), Dentin- (0.70). More radio opaque than GP & dentin
are very much distinguishable on radiographs.
8

9. pH
MTA has a high pH of 12.5 similar to calcium hydroxide cement,
which prevents the bacterial growth and maintains the long lasting
bactericidal potential. Induction of hard tissue formation / barrier in
Apexification procedures and root end filling would minimize the
interaction between material and host tissues
Physical Property
Compressive Strength is an important factor to be considered when
a filling material is placed in a cavity that bears occlusal pressure. As a
root end filling material do not bear direct pressure, the Compressive
strength of this material is not as significant as materials used to repair
defects in occlusal surfaces. Compressive strength in 21days ≈70 Mpa.
Mechanical wear, an important factor in coronal restoration, MTA is not
used as coronal restoration or not placed in functional areas. Erosion of
restorative filling materials can occur either by acids generated by
bacteria, acids present in food or beverages or by mechanical wear.
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10. Advantages
• Antimicrobial Activity
• MicroLeakage
• Cementoconductive
• Non toxic
• Non-mutagenic
• Cell adherence & growth
• Alkaline phosphotase/ osteocalcin
• Interleukin production
• Periodontal ligament attachment to cementum growth
• Dentinal bridge formation
Disadvantages
• More difficult to manipulate
• Longer setting time
•
10

11. Indications
• To preserve pulp vitality
• Prevent pathological changes in the peri - radicular tissues
• Mechanical pulp exposures
• Carious pulp exposures with immature apices
Contra-indications
• Irreversible pulpitis
Clinical Applications
• Direct Pulp Capping
• Apical plug
• Root End Filling
• Perforation Repair
• Furcation involvment
• Resorptive Defects
• Immature apices (apexogenesis/ Apexification)
Pulpotomy
11

12. (Bekir Karabucak et al: dental traumatology 2005)
For Partial Pulpotomy or Cvek Pulpotomy, Formocresol or
Calcium hydroxide based materials has been recommended as a choice of
material to conserve the healthy pulp. Due to its toxic /mutagenic
/carcinogenic effect, MTA was tried for Pulpotomy or Cvek Pulpotomy.
New matrix formation with cellular inclusions and dentin-like barrier at
3rd
wk that found to be successful in preserving the pulpal vitality and
continued development of tooth.
Direct Pulp Capping
In Exposed pulps, to preserve the pulpal vitality, MTA is used as a
pulp capping material. It prevents Bacterial leakage with a high level of
biocompatibility. MTA stimulates dentin bridge formation adjacent to
dental pulp. Dentinogenesis of MTA due to its sealing ability,
biocompatibility, alkalinity and other properties associated with this
material.
Dentin bridge formation that promotes healing. It formed a
complete barrier at exposure site with free of inflammations.
12

13. Reparative dentin formed by MTA does not originate from severely
damaged odontoblasts, but from undifferentiated cells that migrated from
deep regions of pulp, which replaced the degenerated odontoblasts.
Reparative dentin formed is regular and odontoblasts remain intact.
13

14. Root End Filling (Torabinejad et al - 1995 & 1997)
MTA has the ability to prevent the irritants in the root canal to
extrude into periradicular tissues. There is a less inflammation, with
cementum formation and the regeneration of periradicular tissues.
Apical Plug
MTA indicated for Necrotic pulps and With open apices.
MTA can be used as a material of choice fir apical plug and placed 3-
4mm in the apical plug.
It creates a hard tissue formation or as an apical plug to prevent the
extrusion of filling material during obturation of the canal with open
apices.
Retrograde Filling
Jordan in 1998 MTA was tried as retro grade filling material. It
was found that it
Inhibits dye penetration with a
Good sealing ability.
(Nicholson et al: BDJ 2000 188(5); 266-268.)
Root Perforations
14

15. Root perforations can occur during root canal treatment, post space
preparation or as a consequence of internal resorption. MTA can be
placed in the repair area as a reparative material. Repair can be achieved
by Intracoronal / Extracoronal placement.
Lee etal, 1993, found to have less leakage with least overfilling
Nataka, 1997, found that there was least bacterial leakage than amalgam
Pittford, 1995, found that perforated area had non-inflamed surroundings
with cementum formation over MTA.
Furcation Involvement
No inflammation with no loss of periodontal attachment
surrounding MTA. MTA forms cementum and is continuous with
cementum and also forms a hard tissue bridges. MTA extruded into bony
defect cementum formed around excess material and the periodontal
ligament has a separated cementum from bone.
Resorptive Defects
MTA used for repairing the resorptive defects. There will not be
inflammation surrounding it with continuous cementum formation. It
forms a hard tissue bridges also with reduced ostoeclastic activity.
15

16. Comparison of Calcium Hydroxide & MTA
The hard tissue formed, as a calcific bridge with MTA was less
period of time compared with Calcium Hydroxide. MTA forms a thick
dentinal bridge in the pulps capped and the dentinal bridge were
continuous with dentin or dentinal tubules, that are close to pulp with no
tunnel defects. The degree of inflammation is also less with MTA
compared with Calcium Hydroxide. MTA sets hard and prevents
recontamination and seals the pathways of communication between root
canal system and the external surfaces of the teeth.
Calcium hydroxide’s high pH
inhibits essential enzyme activities:
Metabolism, growth and cellular division. A high pH alters integrity of
cytoplasmic membrane by disrupting organic components (proteins and
phospholipids) and interferes with nutrient support. However, intestitial
fluid via crown / apex, necrotic tissue and normal cellular respiration can
partially dissolve Ca (OH)2. Resorption rate of Calcium Hydroxide paste
will vary with density and a rapid barrier formation was related to both
Calcium Hydroxide change rate and a narrow initial apical width. Though
it has many advantages, its disadvantages includes,
• Permeable to fluids
• Soluble in periapical tissues
16

17. • Poor viscosity
• Not easy to apply in RC
• Multiple step Apexification with
• Unpredictability of apical closure
• Patients follow up
• Delay in the completion of treatment
MTA is an
Insoluble matrix of silica that maintains the integrity even in contact with
water. MTA is itself apical barrier material with good sealing ability
properties and a high degree of biocompatibility. MTA has root-end
induction capacity by producing an apical hard tissue formation with
significant greater consistency. MTA is capable of maintaining high pH
during a long time and forms an apical barrier that creates a favorable
environment for cell division and matrix formation. Its advantages over
calcium hydroxide are
One- visit Apexification.
Shortens the treatment time.
Pt’s recall visit is less.
17

18. Ca(OH)2 MTA
Hard tissue formation Not much Root-end induction
Calcific bridge Not Continuous Continuous with
dentin
Period of time More
Tunnel defects
Less
No tunnel defects
Biocompatibility Low High
Degree of
inflammation
High Less
Sets Not hard Hard
Seals the pathways of
communication
Better Good
pH High High
Solubility Partially dissolve Less soluble
Permeable to fluids impermeable
Soluble in periapical
tissues
insoluble
viscosity Poor viscosity good
18

19. Application Not easy to apply in
RC
easy
Resorption Rate vary with density No resorption
Apical barrier formn. Change rate / initial
narrow apical width
Less / wide
Apexification step Multiple One
Apical closure Unpredictability Good
Patients follow up More Less
Treatment Delay Shortens
Sealing Ability Evaluation
Steve Dazey et al: 1990
Luke Moloney et al: 1993
Seung Jong Lee et al: 1993
Mahmoud Torabinejad et al: 1993
Christopher Bates: 1996
John D Welch et al: 1996
Roberto Holland: 1999
Roberto Holland: 2001
Bargholz: 2005
Sarkar et al: 2005
Leakage Evaluation
M Torabinejad et al: 1995
Pitt Ford et al: 1995
19

20. Pitt Ford et al: 1996
Nakata et al: 1998
M Torabinejad et al: 1999
Toh et al: 2003
Bargholz: 2005
Colceriu: 2005
Neurotoxic Evaluation
(Yahshid Asrari: JOE 29(11); Nov 2003.)
Effects of root end filling materials on neurons in primary cortical
cell cultures. Neurons are highly sensitive system to study toxicity.
Neurons are highly susceptible to free-radical-mediated injury, metabolic
injury and environmental toxins. They are much more sensitive than
fibroblasts. Root end materials may absorb by the body, causing systemic
toxicity. There is also possibility that these materials may cause local
neurotoxicity when they are placed near the local nerves and nerve
endings.
Cytotoxic Evaluation
(karl Keiser et al : JOE 26 (5); May 2000)
20

21. MTA is less toxic compared to other root end filling materials.
In 24 hrs, at low concentrations the sequence of toxicity was
Super EBA > MTA / Amalgam
After 24- hrs, at high concentrations, the sequence of toxicity was
Super EBA > Amalgam > MTA
Histologic Evaluation
(Torabinejad et al JOE, 21(12), Dec 1995.)
MTA as a root end filling material does not prevent regeneration of
dental and osseous tissues and induced cementoblasts to produce matrix
for cementum formation over the MTA. The presence of cementum
formation over the MTA in canals obturated with gutta percha either with
or with out a root canal sealer indicated the superior sealing ability of
MTA and its biocompatibility with periradicular tissues. There was an
enhanced cementogenesis, due to its sealing ability or by activation of
cementoblasts to produce cementum formation or by the release of
substances that activate the cementoblasts to laid down a matrix for
cementogenesis. Due to its alkaline pH, the formation of fibrous
connective tissue that was as calcified as the post surgical time interval
21

22. increased with no inflammatory cells in periradicular tissues and reduced
bacterial leakage.
(Torabinejad et al JOE, 23(4), Apr 1997)
MTA has the ability to stimulate the cytokine release from bone
cells and promotes hard tissue formation rather than being inert or being
irritant as a root end filling material. A
Thick layer cementum over MTA was continuous with dentin
incremental lines & cell inclusions. Some of the cementum surface was
characterized by fiber insertion, mimicking sharpeys fibers. The New
cementum was attached to the original cementum. Two possibilities for
the source of the new cementum either derived from the remaining
periodontal ligament or from ingrown connective tissue from bone. If the
cementum had grown lateral aspects, incremental lines run diagonally
from the cementum rather than parallel.
Cellular response to MTA
[Eng Tiong Koh et al: JOE 24(8); Aug, 1998]
Cytokines, are soluble substances that are capable of activating
other cells are released by variety of cells. They are low – molecular wt
glycoproteins secreted as a result of cellular stimulation and are
extremely potent. They interact with cell receptors, leading to a change in
22

23. synthesis of cellular RNA and Protein and therefore they are coordinating
in bone metabolism.
MTA compared with IRM, the tissue response was characterized by
marked rounding of cells and depletion of cell numbers indicating IRM is
toxic.
MTA at 1 & 3 days, the cells observed were normal morphology,
growing in intimate contact with cement and a new hard tissue formation
by measuring the release of cytokines from the bone cells. Small amounts
of IL-1a, IL-1b, IL-6 produced by cells in contact with MTA. The major
Cytokines include ILs and colony stimulating factor. Most ILs cause T
and/or B cell proliferation, and can stimulate by mature Osteoblast.
Cytokines involved in bone formation divided in two groups: first
includes stimulate bone cell proliferation and inhibit mature osteoblasts
and second includes stimulate precursor proliferation and mature
osteoblasts activity.
Conclusion
Thanks to Dr Torabinejad for remarkable material for use in
endodontics. MTA with high biocompatibility, alkalinity, sealing ability
provided hermetic seal. MTA is Panacea for pulpal / periodontal diseases.
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