3. CONTENT
⢠INTRODUCTION
⢠BIOACTIVE MATERIALS
⢠CLASSIFICTION OF BIOACTIVE MATERIALS
⢠BIOACTIVE MATERIALS IN PRACTICE
⢠MTA â
1. HISTORY
2. LIST OF COMMERCIALLY AVAILABLE MTA
3. COMPOSITION
4. MANIPULATION
5. MIXING TIME
6. MECHANISM OF ACTION
7. CLINICAL APPLICATIONS
8. ADVANTAGES
9. DISADVANTAGES
4. ⢠BIODENTINE-
1. COMPOSITION
2. MANIPULATION
3. MIXING TIME
4. SETTING TIME
5. MECHANISM OF ACTION
6. PROPERTIES
7. CLINICAL APPLICATION
8. SUMMERY
⢠CONCLUSION
⢠REFERENCES
5. ⢠Many adhesive dental restorative materials were thought to
have a passive hard tissue interaction based on simple
infiltration with the enamel or dentin.
⢠However, there is increasing interest in studying the bioactivity
of the material.
INTRODUCTION
6. BIOACTIVE MATERIALS
âA bioactive material is one that elicits a specific
biological response at the interface of the material which
results in the formation of a bond between the tissues and the
materialâ.
(1969, Hench)
Hench LL, Splinter RJ, Allen WC, Greenlee TK Jr.; Bonding mechanisms at the
interface of ceramic prosthetic materials. J Biomed Mater Res., 1972; 2:117-141.
7. CLASSIFICATION OF BIOACTIVE
MATERIALS
Osteoproductive
Materials
⢠The bioactive surface is
colonized by osteogenic stem
cells.
⢠Occurs when a material
elicits both an intracellular
and an extracellular response
at its interface.
Osteoconductive
Materials
⢠Materials simply provide a
biocompatible interface along
which bone migrates.
⢠Occurs when a material
elicits only an extracellular
response at its interface.
8. BIOACTIVE MATERIALS IN
PRACTICE
⢠Mineral Trioxide Aggregate
⢠Biodentine
⢠Bioaggregate
⢠Endosequence Root Repair Material
⢠Bioactive Root Canal Sealers
⢠Bioactive luting agents
⢠Calcium enriched mixture
9. MTA
HISTORY:
⢠1993: Introduced to endodontics by M Torabinejad -at loma
linda university,
⢠1998: Took acceptance of U.S. Food and
drug administration,
⢠1999: Commercially released as
ProRoot MTA (DENTSPLY Tulsa, USA)
10. ⢠Most commonly recommended material for sealing
communications between the root canal system and the
periodontium.
⢠MTA was developed and recommended for endodontic
procedures:
1. Nontoxic,
2. Noncarcinogenic,
3. Nongenotoxic,
4. Biocompatible,
5. Insoluble in tissue fluids,
6. Dimensionally stable nature
18. Hydration of MTA
⢠Chemical reaction that leads to the setting of hydrophilic cement is
called âhydrationâ
⢠Components of MTA cement-are partially soluble in water
⢠Soluble components react at different speeds and rates
⢠Heat occurs during the reaction, and new products form
⢠The resulting new products cause the setting of MTA cement and
provide bonding to each other in the content of the components
20. ⢠Calcium silicates (C3S,C2S), calcium aluminates (C3A, C4AF)
and calcium sulphate (CS2H) in the MTAâs structure directly
affects the hydration reaction
Tricalcium silicate (C3S)
⢠It comprises approximately 55% of the volume of MTA
⢠It provides rapid hydration and setting of the cement
⢠It is largely held responsible for initial setting and early strength
3CaOâSiO2+ H2O CaOâ2SiO2â3H2O+ Ca(OH)2
ďś Silicates:
21. Dicalcium silicate (C2S)
⢠It comprises approximately 20% of the volume of MTA
⢠It provides slow hydration and setting
⢠It is largely held responsible for late strength
2CaOâSiO2+ H2O 3CaOâ2SiO2â3H2O+ Ca(OH)2
22. ďś Aluminates
Tetracalcium aluminate (C3A)
⢠Alumina is the combination of calcium oxides with tricalcium
aluminate (C3A) and combination of iron oxides with
tetracalcium aluminoferrite (C4AF)
⢠Aluminites comprise approximately 20% of cement
⢠During hydration, C3A reacts too fast and resists to sulphate
(CS2H)
23. Tetracalcium aluminoferrite (C4AF)
⢠It balances and decreases the heat that occurs during the
setting
⢠Due to the iron component, it causes discoloration
24. Calcium sulphate
⢠It controls the effect of C3A which starts the setting reaction
quickly and reduces the reaction rate
⢠When there is no sulphate in cement (CS2H), the setting occurs
very early
⢠Initial setting of CS2H controls the rise in early strength
25. HYDRATION REACTION
1. Mixing Process
⢠Aluminate and gypsum (caso4â4h2o) dissolve in water and
react within a few minutes
⢠As a result of Rapid dissolution of gypsum added to cement-
Aluminates dissociated from cement- forms a gel-like layer
around the powder particles by reacting with water
⢠Gel like layer prevents- quick reaction of aluminates- rapid
setting of cement
26. 2. Sleep Process
⢠During this process, cement-can be transported, placed or
processed.
⢠The duration might vary with chemical additives.
⢠Rate of heat generation remains almost constant- reaction still
continues.
⢠Cement components dissolve and saturate with water calcium
in the cement (Ca2
+) and hydroxyl (OH-) ions
27. 3. Setting Process
⢠When,water of cement is oversaturated with soluble calcium
ions, new hydration products begin to form- beginning of
setting
⢠The amount of new products formed in the setting period
increases constantly
⢠Resulting product is collected around the hydrophilic particles
that connect each other & surrounds the particles- the cement
starts to set and solidify
28. ⢠Initial setting time: duration between the mixing of MTA
powder with water and the moment when the cement start
precipitation by showing physical changes
⢠Final setting time: duration between the mixing of MTA
powder with water and the moment when the cement solidifies
29. 4. Cooling Process
⢠During this process-âtopochemicalâ reaction occures
⢠Cement has become saturated in terms of components.
⢠Hydration starts at the surface of cement particles (C3S), and
hydration products (C-S-H and CH) are formed at the surface.
⢠The process of cement gaining strength also begins in this
period
30. 5.Concentration Process
⢠The reaction slows down and the heat output is reduced
significantly.
⢠Hydration products continue to generate and develop slowly
⢠Cement reaches the most rigid and robust structural properties
that can be gained
31. ⢠As a result of this reaction, crystal structure of hydrate is
weak which forms a porous solid.
⢠This structure is called âsilica gelâ. Ca ions in silica gel
combine with the OH ion and convert into Ca(OH)2
32.
33. ⢠Once tricalcium aluminate (3CaAl2O4) is hydrated in the
presence of calcium sulphate (CaSO4), it forms ETTRINGITE
(or sulphoaluminat calcium) with high sulphate concentration
34. ⢠Ettringite formation continues until all sulphate ions are used.
⢠Ettringite is converted to monosulphate once sulphate (SO2)
ions are depleted.
⢠The resulting ettringite is disintegrated on the surface of
cement particle and silicate hydrate coating is formed.
⢠After the destruction of the silicate hydrate coating, hydration
can take years.
35. PROPERTIES OF MTA
1.pH: initially-10.2,
after 3 hours- 12.5 (remains constant)
2. Radiopacity: 7-17 mm of equivalent thickness of aluminium
3. Setting time: about 2 hours and 45 minutes
4. Compressive strength: In 24 hours- 40 Mpa
after 21 days: 67Mpa
5. Solubility: no signs of solubility, but if more water is used
during mixing- results into solubility of material
36. 6. Biocompatibility: Promoters regeneration of dental and osseous
tissues, may induce cementoblasts to produce matrix for
cementum formation over MTA
7.Sealing ability: excellent sealing ability, because MTA expands
during setting reaction
⢠In presence of moist environment sealing ability of MTA is
increased
⢠Moistened cotton pellet should be placed in contact with MTA
before placement of the permanent restoration
37. ⢠Acc. To Valois et al. (2004): about 4-mm thickness of MTA is
sufficient to ensure a good sealing
8. Antibacterial and antifungal property: according to Torabinejad
et al. (1995)MTA showed no antimicrobial action against any
of the anerobes
Al-Hazaimi et al. (2006): MTA has antibacterial effect
especially against Enterococcus faecalis and Streptococcus
sanguis
38. 9. Reaction with other dental materials: Acc. Nandini S et al.
(2006): MTA does not react or interfere with any other
restorative material
Acc. Srinivasan V et al (2009): residual calcium hydroxide may
interfere with the adaptation of MTA to dentinal wall- results in
reduced sealing ability which occurs by a mechanical obstacle
of CaOH2 particle by chemically reaction with MTA
39. 10. Biocompatibility : Application of MTA as a root end filling
material promoters regeneration of dental and osseous tissues,
and may induce cementoblasts to produce matrix for
cementum formation over MTA
11. Mineralization: similar to calcium hydroxide (CaOH2), induces
formation of dentin bridge
tricalcium oxide content of MTA interacts with tissue fluids and
form CaOH2, resulting in hard-tissue creation in a similar
manner to that of CaOH2
42. ⢠MTA has been successfully used for the treatment
1. Strip and supracrestal perforations,
2. Horizontal root fractures,
3. Sealing Communications between the root canal space,
4. External root surfaces,
5. Filling root canals of teeth with mature and open apexes,
6. Management of dens invaginatus
46. ⢠Was Commercially available in 2009 (septodont)
⢠Was specifically designed as a âdentine replacementâ material
⢠Actually formulated using the MTA-based cement technology
and the improvement of some properties of these types of
cements
47. COMPOSITION
POWDER
⢠Tri-calcium silicate- main core
material.
⢠Di-calcium silicate-second core
material
⢠Calcium carbonate & oxide-acts
as a filler
⢠Iron oxide-colouring agent
⢠Zirconium oxide- radioopacifier
LIQUID
⢠Calcium chloride-
accelerator
â˘Hydrosoluble polymer-
water reducing agent
48. MANIPULATION
⢠Fine Hydrophilic powder composed of modified powder
composition of MTA
⢠Biodentine is available as powder in a capsule and liquid in a
pipette
49. Mixing time:
⢠The powder is mixed with the liquid in a capsule in the
triturator for 30 seconds
Setting time: Approximately 12 min
50. ⢠The reaction of the powder with the liquid leads to the setting
and hardening of the cement.
⢠The hydration of the tri-calcium silicate leads to the formation
of a hydrated calcium silicate gel and calcium hydroxide
(Taylor et al, 1997).
⢠The cement located in inter
areas has a high level of
calcite content .
Mechanism Of Action
51. ⢠The tri-calcium silicate hydration is achieved by dissolution of
tri-calcium silicate and precipitation of calcium silicate hydrate.
⢠Layers of calcium silicate hydrated gel surround the unreacted
tri-calcium silicate grains, which are relatively impermeable to
water.
⢠Due to permanent hydration of tri-calcium silicate the C-S-H
will form, which gradually fill the space between the grains of
tri-calcium silicate.
52. The following formula shows the complete hydration reaction
(Taylor et al, 1997; Allen et al, 2007).
2(3CaO.SiO2) + 6H2O 3CaO.2SiO2.3H2O + 3Ca (OH)2
53. PROPERTIES OF BIODENTINE
1. Tissue Regeneration & Early Mineralisation : Biodentine
induces early minerlization by increasing the secretion of
TGF-beta1 from pulpal cells after its application.
It also acts by odontoblasts stimulation and cell
differentiation-facilitating reactionary and tertiary dentin
formation.
2. Setting time : 12 mins.
54. 3. Anti bacterial properties : high alkaline pH âinhibitory effect
on microorganisms.
-the alkaline change leads to the disinfection of surrounding
hard and soft tissues.
4. Biocompatibility: preserves pulp vitality and promotes its
healing process.
55. 5. Push Out Bond Strength Of Biodentine: higher push-out bond
strength than MTA
6. Good material handling: ease of manuplation , better
consistency, safety handling with favourable setting kinetics â
about 12minutes
-Absence of post operative pain, when used as a dentin
substitute in class 1 & class 2 composite restorations
56. 7. Specific properties of Biodentine as Dentin Substitute:
Properties Biodentine Dentine
Elastic modulus 22 Gpa 18.5 Gpa
Compressive
strength
220 mpa 290 mpa
Microhardness 60 KHN 63.1 KHN
57. 8. Mariginal Adaptation and Sealing Ability:
⢠The micromechanical adhesion of biodentine -is caused by the
alkaline effect during the setting reaction.
⢠This high pH causes organic tissues to dissolve out of the
dentin tubule.
⢠The alkaline environment at the boundary area of contact
between biodentine and hard tooth substance opens a path via
which the dentin substitute mass can enter the exposed opening
of the dentin canaliculi.
58. ⢠This enables biodentine to be keyed to the dentine by means of
innumerable microscopic cones, creating a stable anchorage
with a sealing-
âBACTERIA-TIGHT EFFECTâ
59. CLINICAL IMPLICATIONS
⢠Pulp capping
⢠Repair of root perforations,
⢠Apexification
⢠Root-end filling
⢠As dentine substitute [base]
for posterior restorations
⢠Resorptive lesions
⢠Retrograde filling
63. MTA BIODENTINE
Advantages High biocompatibility
- Hydrophilic
Radio-opaque
- Highly alkaline ph
- Excellent sealing
ability (Low marginal
leakage)
- Low solubility
release of calcium, a
source of
hydroxyapatite
Sealing
ability
excellent Better than MTA
Solubility Less soluble More soluble
71. CONCLUSION
⢠Disadvantages of calcium hydroxide and MTA has given a
way for the use of biodentine with better results.
⢠Due to major advantages and appreciable properties and ability
to achieve biomimetic mineralisation, biodentine has great
potential to revolutionise the management of affected tooth in
the operative dentistry and endodontics.
⢠However further studies are required to extend the future
scope of this material regarding the clinical applications.
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