Dental Composites: History, Classification, and Properties
2
3
CONTENTS
History
History
Definition
Definition
Classification
Classification
Indication and contraindication
Indication and contraindication
Advantages and disadvantages
Advantages and disadvantages
Composition
Composition
Properties of composite
Properties of composite
4
5
DEFINITION
1.
By Anusavice
By Anusavice
Composite –
in material science, a solid formed from
in material science, a solid formed from
two or more distinct phases (e.g. particles in a metal
two or more distinct phases (e.g. particles in a metal
phase) that have been combined to produce properties
phase) that have been combined to produce properties
superior to or intermediate to those of the individual
superior to or intermediate to those of the individual
constituents
constituents
Dental composite
is defined as a highly cross-linked
is defined as a highly cross-linked
polymeric material reinforced by a dispersion of
polymeric material reinforced by a dispersion of
amorphous silica, glass, crystalline, or organic resin
amorphous silica, glass, crystalline, or organic resin
filler particles and/or short fibers bonded to the matrix
filler particles and/or short fibers bonded to the matrix
by a coupling agent
by a coupling agent
6
Sturdevant
A composite is a physical mixture of the materials.The parts of
the mixture generally is chosen with the purpose of
averaging the properties of the parts to achieve
intermediate properties.
DCNA 2007; Dental materials; vol. 51; July
Composite is a multiphase material that exhibits the properties of
both phases where the phases are complimentary, resulting in a
material with enhanced properties.
DCNA 2007; vol. 50, Aesthetic and cosmetic dentistry
A composite is a multiphase substance formed from a
combination of materials that differ in composition or form, remain
bonded together, and retain their identities and properties.
7
CLASSIFICATION
1
1
.
.
ADA specification No. 27 (JADA Vol. 94, Jun 1977)
ADA specification No. 27 (JADA Vol. 94, Jun 1977)
Type 1
Type 1
:unfilled and filled resins
:unfilled and filled resins
Type 2
Type 2
: composite resin materials to which a filler has
: composite resin materials to which a filler has
been added
been added
2.
2.
Skinner’s classification (10th edition)
Skinner’s classification (10th edition)
•
Traditional composites (Macrofilled) 8-12
Traditional composites (Macrofilled) 8-12
m
m
•
Small particle filled composite – 1-5
Small particle filled composite – 1-5
m
m
•
Microfilled composite – 0.04 – 0.4
Microfilled composite – 0.04 – 0.4
m
m
•
Hybrid composite – 0.6 – 1
Hybrid composite – 0.6 – 1
m
m
8
Lutz and Philips (1983)
Lutz and Philips (1983)
The basis for the
The basis for the
Lutz and Philips (1983) System
Lutz and Philips (1983) System
rests with three types of fillers
rests with three types of fillers
organized into four major classes. The three types of filler particles are
organized into four major classes. The three types of filler particles are
Traditional macro-fillers
Traditional macro-fillers
Microfillers (Pyrogenic silica)
Microfillers (Pyrogenic silica)
Microfiller based complexes, with three subgroups.
Microfiller based complexes, with three subgroups.
Splintered pre-polymerized microfilled complexes (SSP)
Splintered pre-polymerized microfilled complexes (SSP)
Spherical polymer-based microfilled complexes (SphPB)
Spherical polymer-based microfilled complexes (SphPB)
The agglomerated microfiller complexes (AMC
The agglomerated microfiller complexes (AMC
According to Craig
According to Craig
TYPE I
TYPE I
: polymer based materials suitable for restoration ivolving occlusal surfaces
: polymer based materials suitable for restoration ivolving occlusal surfaces
TYPE II
TYPE II
:other polymer based materials
:other polymer based materials
Class 1:self cured materials
Class 1:self cured materials
class 2:light cured materials
class 2:light cured materials
group 1 :energy applied intra orally
group 1 :energy applied intra orally
group 2 :energy applied extra orally
group 2 :energy applied extra orally
9
According to sturdevant (4th edition)
According to sturdevant (4th edition)
Based on range of filler particle size
Based on range of filler particle size
•
Megafill-
Megafill-
β
β
quartz , large size
quartz , large size
•
Macrofill – 10-100
Macrofill – 10-100
m
m
•
Midifill – 1-10
Midifill – 1-10
m
m
•
Minifill – 0.1-1
Minifill – 0.1-1
m
m
•
Microfill – 0.01-0.1
Microfill – 0.01-0.1
m
m
•
Nanofill – 0.005-0.01
Nanofill – 0.005-0.01
m
m
10
Composites with mixed range of particles sizes are
called hybrid and the
largest particle size range is used to define the hybrid type
•
Midifill hybrid
•
Minifill hybrid
According to whether composite is a
homogenous mixture of resin and
filler or includes the pre-cured composite
•
Homogeneous – if composite consists of filler and uncured
matrix material
•
Heterogeneous – if it includes pre-cured composites or other
unusual
filler
11
12
Based on area of application
•
Anterior
•
Posterior composites
Based on method of curing
•
Chemical curing
•
Light curing
•
UV light
•
Visible light
•
Plasma arc
•
Laser curing
•
Dual cure
Based on consistency
Light body – Flowable composite
Medium body – Homogeneous microfills, macrofills and midifills
minifills
Heavy body – Packable hybrid
DCNA (Leinfelder K; Apr; 1985) Classified composites as
conventional composites
Intermediate composite
Hybrid composite
13
According to Marzouk:-
According to Marzouk:-
1
1
st
st
-Macro ceramics
-Macro ceramics
2
2
nd
nd
-Colloidal silica
-Colloidal silica
3
3
rd
rd
-Hybrid :macro and micro colloidal ceramics
-Hybrid :macro and micro colloidal ceramics
4
4
th
th
–Hybrid : heat cured irregularly shaped
–Hybrid : heat cured irregularly shaped
5
5
th
th
-Hybrid : heat cured spherical
-Hybrid : heat cured spherical
6
6
th
th
-Hybrid : agglomerates of sintered micro ceramics
-Hybrid : agglomerates of sintered micro ceramics
14
15
16
17
RESIN MATRIX
PRINCIPAL MONOMERS
BIS-GMA-aromatic-1962-
BOWEN’S RESIN
Bis-GMA structure –
•
The bis-phenol A nucleus:
•
Terminal methacrylate groups
•
Hydroxyl groups
–
18
19
Urethane dimethacrylate-(UDMA)
Triethylene glycol dimethacylate-(TEGDMA)
•
Ratio of Bis-GMA to TEGDMA – 3:1
75wt% bis-GMA,25%wt%TEGDMA-4300centipose
Ratio of Bis-GMA to TEGDMA-1:1
50wt% TEGDMA,50wt% Bis-GMA-200centipose
20
Functions of the diluent –
Reduce the viscosity
Results in higher filler loading.
Results in higher degree of conversion.
Increase the number of cross-linking reactions.
Increases the gelation time
Disadvantage of the diluent
–
Greater polymerization shrinkage.
Increased flexibility.
Decreased abrasion resistance.
Tends to encourage microbial activity – potential for secondary caries
21
Functions of the fillers -
•
Reinforcement of matrix resin resulting in increased
hardness, strength and decreased wear.
•
Reduction in polymerization shrinkage
•
Reduction in thermal contraction and expansion
•
Improved workability by increasing the viscosity
•
Reduction in water sorption, softening and staining
•
Increased radiopacity and diagnostic sensitivity through the
incorporation of strontium (Sr) and barium (Ba) glass and
other heavy metal compounds that absorb X-rays.
fillers
22
Materials used for fillers:-
Materials used for fillers:-
Types of fillers used
Types of fillers used
-ground quartz
-ground quartz
colloidal silica
colloidal silica
glasses or ceramic containing heavy metal
glasses or ceramic containing heavy metal
Other fillers used are –
Other fillers used are –
Amorphous silica
Amorphous silica
Organic filler
Organic filler
Fiber filler
Fiber filler
Single crystal
Single crystal
Crystalline polymers
Crystalline polymers
Fluoride containing fillers
Fluoride containing fillers
23
Filler loading
Filler loading
Between 30 and 70 volume% or 50 to 85 wt% of a composite.
Between 30 and 70 volume% or 50 to 85 wt% of a composite.
The maximum theoretical packing fraction for closed-packed
The maximum theoretical packing fraction for closed-packed
structure is 74 vol%.
structure is 74 vol%.
Filler surface area
Filler surface area
50-400 m
50-400 m
2
2
/gm
/gm
Recent areas of study in fillers –
Recent areas of study in fillers –
Calcium metaphosphate ceramics
Calcium metaphosphate ceramics
Hollow sphere plastic
Hollow sphere plastic
Glass fiber
Glass fiber
Beta-quartz glass inserts
Beta-quartz glass inserts
Fluoride-containing inorganic materials as fillers
Fluoride-containing inorganic materials as fillers
24
COUPLING AGENTS
Essential for bonding of fillers to the resin matrix.
Functions of the coupling agents
•
Bind filler particles to resin.
•
Allow more flexible polymer matrix to transfer stresses
to the higher modulus (more stiffer & stronger) filler
particles
•
Impart improved physical & mechanical properties
•
Inhibit leaching by preventing water from penetrating
along the resin-filler interface.
Types of coupling agents –
Organosilanes – γ-methacryloxypropyl trimethoxysilane
(MPS).
•
Titanates.
•
Zirconates
•
A174 (3-methacryloxy-propyl-trimethoxysilane)
25
26
ACTIVATOR-INITIATOR SYSTEM
Chemically activated
•
Benzoyl peroxide initiator (universal paste)
•
Aromatic tertiary amine activator (N,N, dimethyl-
p
-
toluidine)(catalyst paste)
Light activated
•
Camphorquinone -0.2%-1%
•
Organic aliphatic amine –dimetylaminoethyl methacrylate
(DMAEMA)-0.15%, ethyl-4-dimethylaminobenzoate (EDMAB), or
N,N-cyanoethyl- methylaniline (CEMA)
•
Absorbs blue light with wavelength between 400 and 500 nm
Dual activated composites
27
Inhibitor
“Butylated hydroxytoluine” (BHT), which is used in concentration of
“Butylated hydroxytoluine” (BHT), which is used in concentration of
0.01 wt%. inhibitors have two functions –
0.01 wt%. inhibitors have two functions –
They extend the storage life time for all resins
They extend the storage life time for all resins
They ensure sufficient working time.
They ensure sufficient working time.
Optical modifiers
To match the appearance of teeth
To match the appearance of teeth
commonly titanium dioxide and aluminum oxides are added as
commonly titanium dioxide and aluminum oxides are added as
opacifiers in minute amounts – 0.001 to 0.007 wt%.
opacifiers in minute amounts – 0.001 to 0.007 wt%.
Uv stabilizers
Uv stabilizers
prevents discolouration
2-hydroxy-4 methoxy benzophenone
28
TYPES OF COMPOSITE
29
Traditional composite
Traditional composite
Developed during the 1970s
filler used - finely ground amorphous silica and quartz.
The average particle size is 8 - 12µm,
Filler loading generally is 70 – 80 wt% or 60 – 70 vol%
Indication – used in class II and class IV
30
Clinical considerations
Clinical considerations
Produce rough surface
Produce rough surface
Difficult to polish
Difficult to polish
High initial wear
High initial wear
Can be used for stress bearing areas
Can be used for stress bearing areas
Clinical considerations
Produce rough surface
•
Difficult to polish
•
High initial wear
•
Can be used for stress bearing
areas
31
Properties of traditional composites
Compressive strength-300% to 500%
Elastic modulus -4 to 6 times higher
Resistant to abrasion
High hardness
Water sorption,polmerization shrinkage,thermal expansion
32
Small particle filled composite
Small particle filled composite
Introduced to overcome the disadvantages of traditional
composite
Inorganic fillers are ground to a size range of approximately 0.5 to
3µm, but with a fairly broad size range distribution
Contain more inorganic filler (80 wt% to 90 wt% and 65 to 77
vol%) than traditional composites
Use amorphous silica as filler, but most incorporate glasses that
contain heavy metals for radiopacity Colloidal silica added in
amounts of approximately 5 wt% to adjust the viscosity of paste.
33
Clinical application –
Clinical application –
Indicated for application in which large stresses and abrasion
Indicated for application in which large stresses and abrasion
might be encountered
might be encountered
Attain a reasonably smooth surface for anterior application
Attain a reasonably smooth surface for anterior application
but not as good as hybrid or microfilled composites.
but not as good as hybrid or microfilled composites.
34
Properties of SPF
Superior physical,mechanical properties
Compressive strength,elastic modulus,wear
resistance,surface smoothness
Tensile strength
Polymerization shrinkage,co-efficient of
thermal expansion
35
Microfilled composite
Introduced in 1970s
Individual particles are approximately 0.04 µm (40nm) in size - Colloidal
silica particles
Filler size - 0.004 to 0.4 µm size range.
Inorganic filler content - 35 to 60% by wt.
The greater surface area per unit volume of these microfine particles, the
microfill composites cannot be heavily filled
Approaches to increase the filler loading
Sintering –
Grinding of prepolymerized composites
Final inorganic filler - 50 wt%; if composite particles counted as filler
particles, the filler content is closer to 80 wt% (approx 60 vol %)
36
Clinical consideration –
Clinical consideration –
In stress-bearing situation, the potential for fracture is
In stress-bearing situation, the potential for fracture is
greater
greater
Diamond burs rather than fluted tungsten-carbide burs are
Diamond burs rather than fluted tungsten-carbide burs are
recommended for trimming
recommended for trimming
Low modulus of elasticity – suitable for restoring class V
Low modulus of elasticity – suitable for restoring class V
cervical lesions or defects where cervical flexure can be
cervical lesions or defects where cervical flexure can be
significant
significant
Indications
Indications
Esthetic anterior restoration
Esthetic anterior restoration
Restoring sub-gingival areas
Restoring sub-gingival areas
Carious lesion on smooth surface (Class V)
Carious lesion on smooth surface (Class V)
37
properties
Inferior physical and mechanical properties
Higher co-efficient of thermal expansion decreased elastic modulus
Remain remarkably wear resistant
38
39
Hybrid composites
Hybrid composites
Developed to combine properties of conventional and
microfilled composites
Contain two kinds of filler particles - colloidal silica and
ground particles of glasses containing heavy metals
Content of approximately 75 to 80 wt%.
Average particle size of about 0.4 to 1.0 µm
Colloidal silica represents 10 – 20 wt% of total filler
content.
40
Clinical considerations –
Clinical considerations –
Surface smoothness and reasonably good strength – used in anteriors
Surface smoothness and reasonably good strength – used in anteriors
including Class IV
including Class IV
Few practical differences between hybrid and SPF composites - two
Few practical differences between hybrid and SPF composites - two
terms used interchangeably
terms used interchangeably
Provides a smooth “Platina-like” surface texture in finished restoration.
Provides a smooth “Platina-like” surface texture in finished restoration.
Currently are the predominant direct esthetic restorative material used.
Currently are the predominant direct esthetic restorative material used.
Have almost universal clinical applicability
Have almost universal clinical applicability
41
Chemically cured composite –
Syringes
Tubes
Light-cured composite –
Syringes
Compules
42
•
Supplied as two pastes
•
When the two pastes are spatulated, the amine reacts with the
Benzoylperoxide to form free radicals and polymerization is initiated.
Advantages –
Even polymerization throughout the restoration to maximum 75%
Disadvantages
–
•
Impossible to avoid incorporation of air into the mix forms
pores and weakens the structure.
•
Oxygen inhibition of polymerization during curing
•
No control over the working time
•
Both insertion and contouring must be completed quickly
once the resin components are mixed and placed into the
cavity
•
Often discolors after 3-5 yrs of intraoral service
CHEMICALLY ACTIVATED RESINS
43
Developed To overcome the problems of chemical activation
The first light activated systems were formulated for UV light to
initiate free radicals. Today, the UV light is replaced by visible
blue light-activated systems
Light curable composites are supplied as a single paste contained
in a light-proof syringe
The free radical initiating system, consists of a photosensitizer
and an amine initiator, is contained in this paste
Camphorquinone (CQ) is photosensitizer - absorbs blue light with
wavelengths between 400 and 500nm
Amine initiator is Dimethylaminoethylmathacrylate (DMAEMA)
in case of visible light and Benzoylmethylether in case of UV
light polymerization
44
Advantages –
Advantages –
Easy to use, single paste system
Easy to use, single paste system
Less porosity
Less porosity
Color stability
Color stability
Command polymerization
Command polymerization
Allow operator to complete insertion and contouring before curing is initiated
Allow operator to complete insertion and contouring before curing is initiated
They are not as sensitive to oxygen inhibition as the chemical cured systems
They are not as sensitive to oxygen inhibition as the chemical cured systems
Better mechanical properties
Better mechanical properties
Setting time – faster cure; an exposure of 40 seconds or less is required to
Setting time – faster cure; an exposure of 40 seconds or less is required to
light cure a 2mm thick layer.
light cure a 2mm thick layer.
45
Disadvantages –
Disadvantages –
They must be applied incrementally when the bulk exceeds approx. 2 – 3mm
They must be applied incrementally when the bulk exceeds approx. 2 – 3mm
Limited depth of light penetration
Limited depth of light penetration
Time consuming
Time consuming
Relatively poor accessibility in certain posterior and interproximal locations
Relatively poor accessibility in certain posterior and interproximal locations
Variable exposure times because of shade differences, resulting in longer
Variable exposure times because of shade differences, resulting in longer
exposure times for darker shades and/or increased opacity
exposure times for darker shades and/or increased opacity
Sensitivity to ambient light – leads to formation of a skin or crust when an
Sensitivity to ambient light – leads to formation of a skin or crust when an
opened tube is exposed
opened tube is exposed
Cost of the light curing unit is expensive
Cost of the light curing unit is expensive
Shrinkage towards light source
Shrinkage towards light source
Ocular damage – can cause retinal damage if one looks directly at the beam.
Ocular damage – can cause retinal damage if one looks directly at the beam.
46
47
48
WORKING & SETTING TIME
WORKING & SETTING TIME
Light cure: surface hardens in 60-90 sec
Light cure: surface hardens in 60-90 sec
Chemical cure: 3-5 min
Chemical cure: 3-5 min
Thermal properties –
Thermal properties –
the thermal coefficient of expansion for
the thermal coefficient of expansion for
complete resins is greater than for crown of tooth
complete resins is greater than for crown of tooth
Natural tooth-11.4×10
Natural tooth-11.4×10
-6
-6
Amalgam -25×10
Amalgam -25×10
-6
-6
Hybrid & macrofilled composites-30-40×10
Hybrid & macrofilled composites-30-40×10
-6
-6
49
Polymerization shrinkage –
•
Multipurpose composite – 0.7 to 1.4%
•
Microfill composite – 2 to 3%
•
Packable composite – 0.6 to 0.9%
•
Macrofilled composite – 1.2 to 1.3%
•
Small particle filled composite – 2 to 3%
•
Nanocomposite and other types – yet to be
determined
50
Incremental tecnique
GIC as base
Marginal integrity/marginal leakage –
Marginal integrity/marginal leakage –
(
(
J of General Dentistry; Claudine
J of General Dentistry; Claudine
Agosta; 2003)
Agosta; 2003)
Factors contributing to microleakage –
Factors contributing to microleakage –
Polymerization shrinkage
Polymerization shrinkage
Modulus of elasticity
Modulus of elasticity
Marginal defects related to occlusal loading - Four types
Marginal defects related to occlusal loading - Four types
To enhance the marginal adaptation, reducing the
To enhance the marginal adaptation, reducing the
microleakage of composite restorations - 5 ways
microleakage of composite restorations - 5 ways
(Cheung, J prosth Dent,1990)
(Cheung, J prosth Dent,1990)
Acid etch technique
Acid etch technique
Dentin bonding
Dentin bonding
Cavity design
Cavity design
Incremental technique
Incremental technique
Sealing the margins-unfilled resin
Sealing the margins-unfilled resin
51
Water sorption – (in mg/cm
Water sorption – (in mg/cm
2
2
)
)
Traditional composite – 0.5 to 0.7
Traditional composite – 0.5 to 0.7
Small particle composite – 0.5 to 0.6
Small particle composite – 0.5 to 0.6
Hybrid composite – 0.5 to 0.7
Hybrid composite – 0.5 to 0.7
Microfilled composite – 1.4 to 1.7
Microfilled composite – 1.4 to 1.7
Color stability:-
Color stability:-
Max water sorption-7 to 10 days-3-5µm
Max water sorption-7 to 10 days-3-5µm
Lond term-porosity,roughening
Lond term-porosity,roughening
Two types – internal discoloration and surface staining
Two types – internal discoloration and surface staining
Chemically activated-1 to 3 yrs- yellow-oxidation of
Chemically activated-1 to 3 yrs- yellow-oxidation of
amine-replacement
amine-replacement
Light activated-colour stable
Light activated-colour stable
52
Mechanical properties
Mechanical properties
53
Modulus of elasticity of – (GPa)
Modulus of elasticity of – (GPa)
Traditional composite – 8 to 15gpa
Traditional composite – 8 to 15gpa
Small particle composite – 15 to 20gpa
Small particle composite – 15 to 20gpa
Hybrid composite – 11 to 15gpa
Hybrid composite – 11 to 15gpa
Microfilled composite – 3 to 6.gpa
Microfilled composite – 3 to 6.gpa
Knoop hardness:-measures surface hardness
Knoop hardness:-measures surface hardness
Hybrid and macrofilled – 35 to 65Kg/mm
Hybrid and macrofilled – 35 to 65Kg/mm
2
2
Microfilled composites – 18 to 30Kg/mm
Microfilled composites – 18 to 30Kg/mm
2
2
Bond strength -
Bond strength -
20 and 30 MPa
20 and 30 MPa
54
Clinical properties
Clinical properties
Wear –
Wear –
Ability to resist surface loss
Ability to resist surface loss
Wear resistance of composite are of at
Wear resistance of composite are of at
least five types –
least five types –
Wear by food (CFA wear) (three-body
Wear by food (CFA wear) (three-body
concept)
concept)
Impact by tooth contact in centric
Impact by tooth contact in centric
contacts (occlusal contact area wear)
contacts (occlusal contact area wear)
(two-body concept)
(two-body concept)
Sliding by tooth contact in function
Sliding by tooth contact in function
(functional contact area wear)
(functional contact area wear)
Rubbing by tooth contact
Rubbing by tooth contact
interproximally (proximal contact area
interproximally (proximal contact area
wear)
wear)
Wear from oral prophylaxis methods
Wear from oral prophylaxis methods
(toothbrush or dentifrice abrasion
(toothbrush or dentifrice abrasion
)
)
55
Biocompatibility
Biocompatibility
Direct biological risk
Direct biological risk
Post-placement tooth sensitivity
Post-placement tooth sensitivity
Local immunological effects
Local immunological effects
Apoptotic reactions
Apoptotic reactions
Long-term pulpal inflammation
Long-term pulpal inflammation
Systemic estrogenic effects
Systemic estrogenic effects
May elicit allergic reactions, or may possibly
May elicit allergic reactions, or may possibly
Even act as carcinogens
Even act as carcinogens
Indirect biological risk –
Indirect biological risk –
Post-operative sensitivity, pulpitis, and secondary caries
Post-operative sensitivity, pulpitis, and secondary caries
resulting from microleakage/nanoleakage.
resulting from microleakage/nanoleakage.
56
Minimizing direct biological risks
Cavity preparation
Selection of adhesive system
Conversion of monomers
Minimizing indirect biological risks –
Complete removal of microorganism
Using disinfectants
Embedding bacteria within resin
Selecting an adhesive
Control of polymerization stress
Irritation from activator light –
57
References
References
•
Marwah N. Text book of Pediatric Dentistry, 4
Marwah N. Text book of Pediatric Dentistry, 4
th
th
edition: Jaypee
edition: Jaypee
Brothers Medical Publishers (P) Ltd, New Delhi;2019.
Brothers Medical Publishers (P) Ltd, New Delhi;2019.
•
Thandon S. Pediatric Dentistry, 3
Thandon S. Pediatric Dentistry, 3
rd
rd
edition. Paras
edition. Paras
MedicalPublisher, New Delhi; 2018.
MedicalPublisher, New Delhi; 2018.
•
Philips science of dental materials, Eleventh edition.
Philips science of dental materials, Eleventh edition.
•
Sturdevant’s Art and science of operative dentistry, Fifth edition.
Sturdevant’s Art and science of operative dentistry, Fifth edition.
58
Previous questions
1. Anterior restorative materials( 4M, 2011)
59
60
61
Dental composites are tooth-colored materials developed for natural appearance in dental procedures. They are defined as highly cross-linked polymeric materials reinforced with fillers. This article covers the history, classification, and properties of dental composites, including definitions by experts in the field like Anusavice. Various classifications and types of composites are discussed, providing insight into their composition and advantages in aesthetic and cosmetic dentistry.
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Presentation Transcript
The constant desire of dental profession to achieve a natural appearance has led to development of various tooth coloured material, one among them being DENTAL COMPOSITE
CONTENTS History Definition Classification Indication and contraindication Advantages and disadvantages Composition Properties of composite
DEFINITION By Anusavice 1. Composite in material science, a solid formed from two or more distinct phases (e.g. particles in a metal phase) that have been combined to produce properties superior to or intermediate to those of the individual constituents Dental composite is defined as a highly cross-linked polymeric material reinforced by a dispersion of amorphous silica, glass, crystalline, or organic resin filler particles and/or short fibers bonded to the matrix by a coupling agent
DCNA 2007; Dental materials; vol. 51; July Composite is a multiphase material that exhibits the properties of both phases where the phases are complimentary, resulting in a material with enhanced properties. DCNA 2007; vol. 50, Aesthetic and cosmetic dentistry A composite is a multiphase substance formed from a combination of materials that differ in composition or form, remain bonded together, and retain their identities and properties. Sturdevant A composite is a physical mixture of the materials.The parts of the mixture generally is chosen with the purpose of averaging the properties of the parts to achieve intermediate properties.
CLASSIFICATION 1. ADA specification No. 27 (JADA Vol. 94, Jun 1977) Type 1:unfilled and filled resins Type 2: composite resin materials to which a filler has been added 2. Skinner s classification (10th edition) Traditional composites (Macrofilled) 8-12 m Small particle filled composite 1-5 m Microfilled composite 0.04 0.4 m Hybrid composite 0.6 1 m
Lutz and Philips (1983) The basis for the Lutz and Philips (1983) System rests with three types of fillers organized into four major classes. The three types of filler particles are Traditional macro-fillers Microfillers (Pyrogenic silica) Microfiller based complexes, with three subgroups. Splintered pre-polymerized microfilled complexes (SSP) Spherical polymer-based microfilled complexes (SphPB) The agglomerated microfiller complexes (AMC According to Craig TYPE I : polymer based materials suitable for restoration ivolving occlusal surfaces TYPE II :other polymer based materials Class 1:self cured materials class 2:light cured materials group 1 :energy applied intra orally group 2 :energy applied extra orally
According to sturdevant (4th edition) Based on range of filler particle size Megafill- quartz , large size Macrofill 10-100 m Midifill 1-10 m Minifill 0.1-1 m Microfill 0.01-0.1 m Nanofill 0.005-0.01 m
Composites with mixed range of particles sizes are called hybrid and the largest particle size range is used to define the hybrid type Midifill hybrid Minifill hybrid According to whether composite is a homogenous mixture of resin and filler or includes the pre-cured composite Homogeneous if composite consists of filler and uncured matrix material Heterogeneous if it includes pre-cured composites or other unusual filler
Based on area of application Anterior Posterior composites Based on method of curing Chemical curing Light curing UV light Visible light Plasma arc Laser curing Dual cure Based on consistency Light body Flowable composite Medium body Homogeneous microfills, macrofills and midifills minifills Heavy body Packable hybrid DCNA (Leinfelder K; Apr; 1985) Classified composites as conventional composites Intermediate composite Hybrid composite
According to Marzouk:- 1st -Macro ceramics 2nd -Colloidal silica 3rd -Hybrid :macro and micro colloidal ceramics 4th Hybrid : heat cured irregularly shaped 5th -Hybrid : heat cured spherical 6th -Hybrid : agglomerates of sintered micro ceramics
INDICATIONS CONTRAINDICATIONS When proper isolation is not possible Class I, II, III, IV, V, VI restorations Foundations or core buildups When occlusion is on composite restoration Sealants and preventive resin restorations When preparation extending on root surface or subgingival area Poor oral hygiene Esthetic enhancement procedures Cements (for indirect restorations) High caries index Temporary restorations Patient s with abnormal habits (bruxism) For splinting Subgingival area/root surface Non caries lesions like abrasion erosion Enamel hypoplasia Composite inlays and onlays Repair of old composite restoration
ADVANTAGES DISADVANTAGES Esthetics Technique sensitive Conservation of tooth structure Polymerization shrinkage Less complex when preparing the tooth Higher coefficient of thermal expansion Insulative having low thermal conductivity Difficult time consuming Used almost universally Increased occlusal wear Bonded to tooth structure (good retention) Low modulus of elasticity Repairable Bio-compatibility ? No corrosion Staining Strengthening of tooth structure Costly
Composition Resin matrix Optical modifiers Coupling agent Inhibitor Fillers Activator and initiator
RESIN MATRIX PRINCIPAL MONOMERS BIS-GMA-aromatic-1962-BOWEN S RESIN Bis-GMA structure The bis-phenol A nucleus: Terminal methacrylate groups Hydroxyl groups
ADVANTAGES DISADVANTAGES High molecular weight Difficult to crystallize and purify Extensive cross-linking- increases rigidity High molecular weight increase viscosity Decreased polymerization shrinkage Stability of color is questionable Non-volatile It produces less heat during polymerization.
DILUENT MONOMERS Urethane dimethacrylate-(UDMA) Triethylene glycol dimethacylate-(TEGDMA) Ratio of Bis-GMA to TEGDMA 3:1 75wt% bis-GMA,25%wt%TEGDMA-4300centipose Ratio of Bis-GMA to TEGDMA-1:1 50wt% TEGDMA,50wt% Bis-GMA-200centipose
Functions of the diluent Reduce the viscosity Results in higher filler loading. Results in higher degree of conversion. Increase the number of cross-linking reactions. Increases the gelation time Disadvantage of the diluent Greater polymerization shrinkage. Increased flexibility. Decreased abrasion resistance. Tends to encourage microbial activity potential for secondary caries
fillers fillers Functions of the fillers - Reinforcement of matrix resin resulting in increased hardness, strength and decreased wear. Reduction in polymerization shrinkage Reduction in thermal contraction and expansion Improved workability by increasing the viscosity Reduction in water sorption, softening and staining Increased radiopacity and diagnostic sensitivity through the incorporation of strontium (Sr) and barium (Ba) glass and other heavy metal compounds that absorb X-rays.
Materials used for fillers:- Types of fillers used -ground quartz colloidal silica glasses or ceramic containing heavy metal Other fillers used are Amorphous silica Organic filler Fiber filler Single crystal Crystalline polymers Fluoride containing fillers
Filler loading Between 30 and 70 volume% or 50 to 85 wt% of a composite. The maximum theoretical packing fraction for closed-packed structure is 74 vol%. Filler surface area 50-400 m2/gm Recent areas of study in fillers Calcium metaphosphate ceramics Hollow sphere plastic Glass fiber Beta-quartz glass inserts Fluoride-containing inorganic materials as fillers
COUPLING AGENTS Essential for bonding of fillers to the resin matrix. Functions of the coupling agents Bind filler particles to resin. Allow more flexible polymer matrix to transfer stresses to the higher modulus (more stiffer & stronger) filler particles Impart improved physical & mechanical properties Inhibit leaching by preventing water from penetrating along the resin-filler interface. Types of coupling agents Organosilanes -methacryloxypropyl trimethoxysilane (MPS). Titanates. Zirconates A174 (3-methacryloxy-propyl-trimethoxysilane)
ACTIVATOR-INITIATOR SYSTEM Chemically activated Benzoyl peroxide initiator (universal paste) Aromatic tertiary amine activator (N,N, dimethyl-p- toluidine)(catalyst paste) Light activated Camphorquinone -0.2%-1% Organic aliphatic amine dimetylaminoethyl methacrylate (DMAEMA)-0.15%, ethyl-4-dimethylaminobenzoate (EDMAB), or N,N-cyanoethyl- methylaniline (CEMA) Absorbs blue light with wavelength between 400 and 500 nm Dual activated composites
Inhibitor Butylated hydroxytoluine (BHT), which is used in concentration of 0.01 wt%. inhibitors have two functions They extend the storage life time for all resins They ensure sufficient working time. Optical modifiers To match the appearance of teeth commonly titanium dioxide and aluminum oxides are added as opacifiers in minute amounts 0.001 to 0.007 wt%. Uv stabilizers prevents discolouration 2-hydroxy-4 methoxy benzophenone
TYPES OF COMPOSITE Conventional /traditional composite Small particle filled composite Microfilled composite Hybrid composite
Traditional composite Developed during the 1970s filler used - finely ground amorphous silica and quartz. The average particle size is 8 - 12 m, Filler loading generally is 70 80 wt% or 60 70 vol% Indication used in class II and class IV
Clinical considerations Produce rough surface Difficult to polish High initial wear Can be used for stress bearing areas Clinical considerations Produce rough surface Difficult to polish High initial wear Can be used for stress bearing areas strength Advantages Disadvantages Compressive, tensile Polishability Surface roughness Stiffness Staining, plaque Hardness Occlusal wear Polymerization shrinkage Poor esthetics Water sorption, thermal expansion
Properties of traditional composites Compressive strength-300% to 500% Elastic modulus -4 to 6 times higher Water sorption,polmerization shrinkage,thermal expansion Resistant to abrasion High hardness
Small particle filled composite Introduced to overcome the disadvantages of traditional composite Inorganic fillers are ground to a size range of approximately 0.5 to 3 m, but with a fairly broad size range distribution Contain more inorganic filler (80 wt% to 90 wt% and 65 to 77 vol%) than traditional composites Use amorphous silica as filler, but most incorporate glasses that contain heavy metals for radiopacity Colloidal silica added in amounts of approximately 5 wt% to adjust the viscosity of paste.
Clinical application Indicated for application in which large stresses and abrasion might be encountered Attain a reasonably smooth surface for anterior application but not as good as hybrid or microfilled composites. Advantages Disadvantages Good mechanical properties Prone to wear and deterioration. Good smoothness Less polymerization Shrinkage Radiopacity Wear resistance
Properties of SPF Superior physical,mechanical properties Compressive strength,elastic modulus,wear resistance,surface smoothness Tensile strength Polymerization shrinkage,co-efficient of thermal expansion
Microfilled composite Introduced in 1970s Individual particles are approximately 0.04 m (40nm) in size - Colloidal silica particles Ground polymer with colloidal silica (50 u) Filler size - 0.004 to 0.4 m size range. Polymer matrix with colloidal silica Inorganic filler content - 35 to 60% by wt. The greater surface area per unit volume of these microfine particles, the microfill composites cannot be heavily filled Approaches to increase the filler loading Sintering Grinding of prepolymerized composites Final inorganic filler - 50 wt%; if composite particles counted as filler particles, the filler content is closer to 80 wt% (approx 60 vol %)
Clinical consideration In stress-bearing situation, the potential for fracture is greater Diamond burs rather than fluted tungsten-carbide burs are recommended for trimming Low modulus of elasticity suitable for restoring class V cervical lesions or defects where cervical flexure can be significant Indications Esthetic anterior restoration Restoring sub-gingival areas Carious lesion on smooth surface (Class V)
properties Inferior physical and mechanical properties Higher co-efficient of thermal expansion decreased elastic modulus Remain remarkably wear resistant
Advantages Disadvantages Best surface finish Tensile strength Excellent wear resistance Water sorption and CTE fracture resistance Radiolucent Polymerization shrinkage
Hybrid composites Developed to combine properties of conventional and microfilled composites Contain two kinds of filler particles - colloidal silica and ground particles of glasses containing heavy metals Content of approximately 75 to 80 wt%. Average particle size of about 0.4 to 1.0 m Colloidal silica represents 10 20 wt% of total filler content. Silane-coated silica or glass Polymer matrix with colloidal silica
Clinical considerations Surface smoothness and reasonably good strength used in anteriors including Class IV Few practical differences between hybrid and SPF composites - two terms used interchangeably Provides a smooth Platina-like surface texture in finished restoration. Currently are the predominant direct esthetic restorative material used. Have almost universal clinical applicability Advantages Disadvantages Good physical properties Improve wear resistance Increased surface roughness with time Superior surface morphology Good esthetics
Chemically cured composite Syringes Tubes Light-cured composite Syringes Compules Enlarge picture
CHEMICALLY ACTIVATED RESINS Supplied as two pastes When the two pastes are spatulated, the amine reacts with the Benzoylperoxide to form free radicals and polymerization is initiated. Advantages Even polymerization throughout the restoration to maximum 75% Disadvantages Impossible to avoid incorporation of air into the mix forms pores and weakens the structure. Oxygen inhibition of polymerization during curing No control over the working time Both insertion and contouring must be completed quickly once the resin components are mixed and placed into the cavity Often discolors after 3-5 yrs of intraoral service
Light-cured composites Developed To overcome the problems of chemical activation The first light activated systems were formulated for UV light to initiate free radicals. Today, the UV light is replaced by visible blue light-activated systems Light curable composites are supplied as a single paste contained in a light-proof syringe The free radical initiating system, consists of a photosensitizer and an amine initiator, is contained in this paste Camphorquinone (CQ) is photosensitizer - absorbs blue light with wavelengths between 400 and 500nm Amine initiator is Dimethylaminoethylmathacrylate (DMAEMA) in case of visible light and Benzoylmethylether in case of UV light polymerization
Advantages Easy to use, single paste system Less porosity Color stability Command polymerization Allow operator to complete insertion and contouring before curing is initiated They are not as sensitive to oxygen inhibition as the chemical cured systems Better mechanical properties Setting time faster cure; an exposure of 40 seconds or less is required to light cure a 2mm thick layer.
Disadvantages They must be applied incrementally when the bulk exceeds approx. 2 3mm Limited depth of light penetration Time consuming Relatively poor accessibility in certain posterior and interproximal locations Variable exposure times because of shade differences, resulting in longer exposure times for darker shades and/or increased opacity Sensitivity to ambient light leads to formation of a skin or crust when an opened tube is exposed Cost of the light curing unit is expensive Shrinkage towards light source Ocular damage can cause retinal damage if one looks directly at the beam.
Chemical Light cure Polymerization is central Peripheral Curing is one phase Is in increments Sets within 45 seconds Sets only after light activation No control over working time Working time under control Shrinkage towards centre of bulk Shrinkage towards light source Air may get incorporated Less chance of air entrapment More wastage of material Less wastage Not properly finished Better finish
Properties Physical Mechanical Clinical
WORKING & SETTING TIME Light cure: surface hardens in 60-90 sec Chemical cure: 3-5 min Thermal properties the thermal coefficient of expansion for complete resins is greater than for crown of tooth Natural tooth-11.4 10-6 Amalgam -25 10-6 Hybrid & macrofilled composites-30-40 10-6
Polymerization shrinkage Multipurpose composite 0.7 to 1.4% Microfill composite 2 to 3% Packable composite 0.6 to 0.9% Macrofilled composite 1.2 to 1.3% Small particle filled composite 2 to 3% Nanocomposite and other types yet to be determined Incremental tecnique GIC as base
