Applied Dental Material Second Year

1. ‫يِ َدْ يِ يِ َّ َدْ يِ ر يِ يِ‬
‫بسم حاهلل حالرحنمل ن حال َّحميم‬
‫}وحاحلل عقدة مل ن لسنان ي‬
‫ِناَ َدْقُ َدْ قُ َدْ ِناَ م ً ِّ ِّ ِناَ يِ‬
‫}يفقهوحا قول ي }82‬
‫ِناَ َدْ ِناَ قُ ِناَ َدْيِ‬
‫}72‬
‫حالﻌﻅيم صدق حاهلل‬

2. Aesthetic Restorative Materials

3. Types of aesthetic restorative materials:
Silicate cements.
Glass Ionomer.
Unfilled Resin.
 Filled Resin.
 Ceramics

4. Unfilled Resin (PolymericMaterial)
SELF CURED ACRYLIC RESIN
DIRECT RESTORATIVE
MATERIAL

5. Composition:
Powder
PMM
 Initiator (benzoyl
peroxide)
 Pigments

Setting reaction:
Addition polymerization
Liquid
Methyl methacrylate
together
 Chemical activator
(dimethyl para
toluidine)
 An inhibitor
(hydroquinone) to
prevent polymerization
on storage.


7. 





Disadvantages:
Residual monomer
Heat evolution
Polymerization shrinkage
Water sorption
Large mismatching in coefficient of
thermal expansion &contraction between
the filling &the tooth leading to marginal
percolation.

9. Disadvantages:





Aesthetics: Initially excellent aesthetics can
be achieved, however, over a period of time,
staining is evident at the cavity margins.
No adhesive bond between the filling &
tooth
High volatility
Weak mechanical properties
Radiolucent

10. Advantages:
It matches the tooth in color, refractive
index & translucency.
Very limited solubility.

11. Filled Resin
Composite filling material

12. 
A composite is a combination of two or
more chemically different materials with a
distinct interface separating the components
and having properties which could not be
achieved by any of the components alone.

13. Composition
1.
2.
3.
4.
5.
Organic matrix phase.(polymeric phase)
Inorganic filler phase.(inert phase)
Coupling agent which binds the inorganic
fillers to the organic matrix
Initiator activator systems for organic phase.
Other components for organic phase
•
•
•
Inhibitors .
Ultraviolet stabilizers.
Pigments.

14. Composition:
N.B.:
For a composite resin material with successful
properties,there should be
Not less than 50 weight% inorganic filler in the
organic matrix.
Chemical bond between the inorganic filler&the
organic matrix

15. I.
a


Organic matrix phase
MW monomer(oligomer)
Properties of oligomer:
It has the same disadvantages of MMA
monomer BUT TO LESSER EXTENT.
It produces stronger & stiffer matrix

16. Type of oligomer:
Bisphenol A- glycidyl methacrylate (BIS-GMA)
which is called Bowen’s resin.
or
Urethane dimethacrylates (UDMA).
In some products mixture of the two oligomers is
present.

17. The main disadvantage of the oligomer is the high
viscosity.
Therefore it should be mixed with lower MW
monomer(diluent) in ratio of 75% oligomer to 25%
monomer.

18. 
b-Low M.W. monomer (diluent)




Reduce the viscosity of the oligomer in
order to facilitate
Blending with inorganic filler
Clinical manipulation
Crosslinking between the polymer
chains

19. Recently Ormocer:
They
are
materials
polymeric
inorganic-organic
hybride
Inorganic polysiloxane polymer network has been
selectively modified by chemically bonded organic
methacrylate group.

20. Advantage:

Less polymerization shrinkage compared to other
oligomer.

21. Other modification
Siloranes
These are composites whose oligomers
undergo ring opening polymerization
Therefore they undergo expansion rather than
contraction during polymerization

22. Role of organic matrix:
The organic matrix is the soft moldable phase
which undergoes addition poly_
merization to form a crosslinked polymer
holding the inorganic filler particles together
and bonding to tooth structure.

23. II.
Inorganic fillers ( reinforcing fillers)
Role:
a.
•
Improvement in mechanical properties such
as compressive strength, modulus of
elasticity and hardness.
•
Reduction
expansion.
•
Reduction in the polymerization shrinkage.
Less heat evolved in polymerization.
•
in
coefficient
of
thermal

24. •
•
•
•
•
Less water sorption.
Less residual monomer.
Filler is able to reflect the color of the tooth.
The refractive index of the filler matches that of
that of the matrix
The filler imparts radioopacity.

25. b) Type of inorganic filler
 Quartz:
strong,very hard,chemically stable in oral
environment,radiolucent.
 Fused silica:
softer material,easier to grind.
 Heavy metal containing glasses:
softer material,some types are not stable in oral
environment,easier to grind,radioopaque.

26. c)Filler particle loading and size:

27. Filler loading:
It refers to the amount of filler in the matrix.It can be
expressed as volume or weight%.
As a guide,the volume % is less than the weight% by 10
-15% ,since the filler is of high density.
The filler loading determines the properties of the
composite.

28. For best achievment,we should maximize the filler
percentage,keeping in mind that all the filler
particles should be wetted by the resin matrix and
aiso proper consistency for clinical manipulation
should be obtained.

29. The particle size:
 The particle size of the filler and its distribution is
important because:
 It determines the amount of the filler that can be added
without increasing the consistency ;as the smaller the
filler,the thicker the consistency i.e.we can not maximize
the small filler ,because it will increase the consistency
making the clinical manipulation difficult.
 It determines the surface finish of the restoration;as the
smaller the filler,the smoother the surface finish.

30. THEREFORE COMPOSITE
RESIN CAN BE
CLASSIFIED ACCORDING
TO FILLER SIZE AND
LOADING INTO:

31. The particle size:
 Conventional composite resin:
It is a historical type.
Particle size:10 -25microns( large particle)
Filler loading:70 weight%
Comment:
Improvement in all properties
Poor surface quality due to wear of the resin
matrix and protrusion of the filler leading to rough
surface,plaque accumulation and discoloration.

32. The particle size:
 Fine composite resin:
Both new softer filler type and recent
grinding technology allow for the
introduction of this and the following
types.
Particle size:0.4_3 microns
Filler loading:75weight%
Comment:
Improvement in all properties with better surface
quality
and optical properties.

33.  Microfine filler :
Particle size:0.04_0.2µm(high surface area)
Filler loading:only 30weight% without
increasing the
clinical consistency of the mix
Comment: No improvement.
What is the solution?

34. Particle size:0.04_0.2 microns(30%)

+ Agglomerated microfine
or
prepolymerized particles 10_20µm(30%)
Filler loading:60 weight%
Comment:
Best surface finish with less improvement in
other properties.

35.  Hybrid composite:
 Particle size:It is a blend of filler sizes to obtain the
properties of fine &microfine composites, containing
mostly fine particles with 5-15% microfine particles.
 This distribution permits more efficient packing,
where the smaller particles fill the spaces between the
larger particles.
 Filler loading: 85 weight%
 Comment:
 Best properties among all composites.

36. Recently nanotechnology has been used to produce
composite resin with 2-20 nm silica nanoparticles&
0.6µm zirconia_silica nanoclusters.

39. 3- Coupling agent
Force

40. Type of coupling agent:
Silanes
Role:
It binds the inorganic filler with the organic
matrix chemically to enable stresses to be
transferred from particle to adjacent
particles through the organic matrix i.e.all
act as one unit.
But this bond degrades, when water is absorbed by the
composite intraorally.

41. Initiator Activator System
Role of initiator activator system:
To cause addition polymerization of the
organic matrix.
Types of initiator activator system:

42. Initiator Activator System
a. Chemical activation: Self-,cold-,automatic
cured(initiated) Aromatic tertiary amine activate
benzoyl peroxide to produce free radicals.
b. Light activation: Photo cured( initiated)
There are 2 types:
a. Ultra violet activation (not used because of health
hazards&limited depth of cure)

43. b. Blue visible light activation:
 ~470 nm wavelength

44. Diketone
In the presence of blue visible light
Excited state
In the presence of aliphatic
tertiary amine
Free radical

45. Comparison:
Chemically cured C.R.
Light cured C.R.
 Supplied as 2 pastes.
 Proportionong.
 Mixing.
 Air inclusion.
 Human variables.
 Limited working time,as
 Supplied as one paste.
 No proportioning
setting starts after
mixing immediately
 Less colour stable due to
oxidation of aromatic
tertiary amines
 Bulk insertion
 No mixing
 No air inclusion
 No human variables
 Long working time,as
setting starts upon light
irradiation
 More colour stable due to
presence of aliphatic
tertiary amines& even in
less amount

46. The depth of cure :
Definition:
It is the thickness of C.R. completely penetrated
by the visible blue light & polymerized.
Factors affecting the depth of cure:
1. The intensity of the light source(normal output is
400J/cm square)
2. The exposure time( normal exposure time is
20_40 seconds)
3. The distance between the light source & the
restoration(ideal is 1mm with the light source
positioned 90degrees from the C.R.surface.

47. The depth of cure :
4. The type of C.R. regarding:
a) The shade( lighter shade has greater depth of
cure)
b) The filler size & loading(the larger the filler
with greater loading to certain extent,the
greater depth of cure)
c) The absorption coefficient of initiator
activator system(light sensitivity&amount)
5. Air inhibition

48. N.B.
Care should be taken to avoid
unpolymerized material in the base of
cavities . Composite resin which is not
fully polymerized will show reduced
mechanical properties, poorer colour
stability and greater susceptibility to
stain.

49. N.B.
Not all the available carbon double bond in the
organic matrix convert into single bond;~25%
remain uncoverted in the bulk of the restoration.
Keep in mind, the higher the degree of
conversion,the better the properties of C.R.

52. A.Polymerization inhibitor:
i. It extends the shelf life by preventing
premature polymerization.
ii. It provide suitable working time.
B. Ultraviolet stabilizer:
It protects against yellowish discoloration
by time.
C .Fluorescent agent&Pigment:
To simulate the tooth

53. Classification of C.R.:
According to filler size & loading
According to initiation activation system
According to method of application
According to handling

54. a) According to filler size & loading:
1) Conventional C.R.
2) Fine C.R.
3) Microfine C.R.
4) Hybrid C.R.

55. b- According to initiation activation system:
• Chemically cured composite
• Light cured composite
• Dual cured composite:It is applied in resin
cement & indirect restoration.( combination
of heat,chemical or light curing)

56. C )Restorations
Direct restorations
Indirect restorations

57. Composite inlay:
 composite inlay systems are polymerized
outside or inside the patient mouth and
then removed from the prepared cavity
by the help of separating medium.
 The inlay is then subjected to post-curing
by additional light (6minutes) or heat
(about 100°C for 7 minutes).
 The preparation is etched.
 The inlay is then cemented to the
prepared cavity with a dual cure resin and
is then polished.

58.  Purpose of indirect restoration (laboratory composites)
I. Increase degree of conversion of oligomer to polymer by dual
curing thus increasing the mechanical properties&colour
stability.
2. No weakening effect on tooth composite bond,as the
polymerization shrinkage of the C.R. occurs completely outside
the patient s mouth.
 N.B.
• Only the polymerization shrinkage of the thin film of the resin
cement ,used for the cementation of the indirect restoration
,occurs inside the patient s mouth.

59. d)
According to handling:Regarding the filler
size,shape&loading beside resin formulation,there are2
types:

Flowable C.R.:It has very low viscosity& high flow allowing
for better adaptation.It is used for cervical lesion,pediatric
lesion&in combination with packable C.R.
Packable C.R.:It has very high viscosity&low surface
tackiness.It can be compressed against the cavity
walls&margins for proper adaptation.It can be used for
class one& class two.


60. Properties of C.R.:
The properties of C.R. is related tothe 1)amount of
inorganic filler,as it reduces the percentage of the
organic matrix & consequently its disadvantages.
The inorganic filler acts as mechanical skeletal
structure within the C.R. to maintain the original
amount.
2)The degree of conversion of carbon double bond into
single bond in the organic matrix.The higher the
degree of conversion,the better the properties C.R.

61. 1) Biological properties:
C.R. is irritant to the pulp because of heat
evolution,shrinkage&residual monomer
during polymerization reaction.
Therefore C.R. should be lined by calcium
hydroxide.
The irritation ranking is as follows:
microfilled>conventional>fine>hybrid.

62. 2) Solubility&water sorption:





Composites have a very low solubility. But it absorb
water due to its polarity.
The
ranking
of
water
sorption
is
a
follows:microfilled>conventional>fine>hybrid
N.B.
UDMA shows less water sorption
Some inorganic filler are more liable to hydrolyti
degradation
than
others,
e.g.barium,strontium
containing glasses.

63. 3)Dimensional changes on
setting:
 C.R. undergo polymerization shrinkage,,due to closer spacing in
the polymer when compared to that in the oligomer.
 The ranking of polymerization shrinkage is as follows:
microfilled>conventional>fine>hybrid.
 The consequences of polymerization shrinkage are :
- Weakening of tooth composite bond
- Marginal leakage
- Discoloration
- Recurrent caries
 These can be reduced by:
1)Incremental filling(light cured)
2)Indirect restoration
3)Curing mode (light intensity is delivered at

64. 3)Dimensional changes on
setting:
slow rate to allow for the flow of C.R.relieving the
polymerization stresses.
4)Water sorption
5)Use of elastic wall concept by the application of
intermediate lining of lower elastic modulus.
6)Use of ormocer or silorane
7)Establish strong bond between the tooth&C.R.

66. 4) Thermal properties:
Thermal conductivity: The thermal
conductivity values are lower than those for
metallic restorations .
It is related to the higher conductivity of the
inorganic fillers compared with the organic
matrix.
The ranking is as follows:
Hybrid>fine>conventional>microfilled.
However it does not present a clinical
problem.

67. 4)Thermal properties:
Coefficient of thermal expansion:
It is~double than that of tooth structure.
The ranking is as follows:
Microfilled>conventional>fine>hybrid
This mismatch leads to the same consequences
as in polymerization shrinkage

68. 6- Mechanical properties:
C.R is a brittle material,i.e.
stronger in compression than in tension.
 Polymerization may continue for 24 hours
after clinical curing,thereby improving in
mechanical properties
 The ranking is as follows:
Hybrid>fine>conventional>microfilled


69. 7) Aesthetic and optical
properties:



Aesthetic is initially excellent;but
by time there will be
discoloration because of the
following:
Oxidation of aromatic tertiary
amine in self cured C.R.
The polymer matrix wears more
rapidly than the inorganic filler
leading to rough
surface&accumulation of
plaque&stains

70. Water sorption of C.R. leads to partial debonding of
the inorganic filler&stress cracks in the polymer
matrix decreasing the translucency of the material.
Polymerization shrinkage leading to marginal
ieakage.
Mismatching in coefficient of thermal expantion
&contraction between the tooth &C.R.leading to
marginal leakage.

71. Only theC.R. with heavy metal containing glasses
e.g.barium,boron,strontium,zirconium,oryetribium
are radioopaque to detect defective filling&recurrent
caries.
The ranking of best surface finish against the plastic
matrix is as follows:
Hybrid>microfilled>fine>conventional

73. 8) Bonding and retention to tooth
structure:
Bonding to enamel:
It is a micromechanical attachment with
the following steps:
 Acid etching to produce surface
irregularities
 Bonding agent to enable penetration of the
C.R.&bonding to it.


75. Bonding to dentin:
It is a micromechanical attachment with
the following steps:
Etching to produce surface irregulrities
&to remove smear layer
Application of primer to wet the dentin
& to bind to the bonding agent
Application of bonding agent

77. 9)Shelf life:
All C.R. have a limited shelf life~2years.
Therefore C.R. should be stored under
refrigeration & allowed to come to room
temperature for ~1hour before use.
Light cured C.R.should be stored away from
ambient light.
C.R. contain volatile components.
Therefore C.R.should be dispensed
immediately before use &resealed also
immediately.

78. Applications of composites:






Direct anterior restorations.
Direct posterior restorations
Core build up materials
Provisional restorations
Lower viscosity C.R. used as pit & fissure
sealant,luting &bonding agents
Laboratory C.R. for indirect restoration
These may contain fibres instead of particles.

81. Setting reaction: