Dr. Mayank Nahta presented on dental composites. Composites are polymers reinforced with filler particles that are bound together. Dr. Ray Bowen developed the first dental composite in 1962 using Bis-GMA resin and glass/quartz fillers. Composites are used for restorations, veneers, cores, and more. They are classified based on properties like filler size, composition, and curing method. Composites provide strength, polishability, aesthetics, and more depending on their formulation. Developments include microfilled, small particle, hybrid, and flowable composites to optimize properties.

1. Presented by- Dr. Mayank Nahta
Rungta college of dental sciences and research,
Bhilai

2. CONTENT
• INTRODUCTION
• HISTORY
• USES
• CLASSIFICATION
• COMPOSITION

3. INTRODUCTION
• They are highly crosslinked polymeric materials reinforced by a
dispersion of glass,crystalline or resin filler particles or short fibres
bound to the matrix by silane coupling agents.
• It may be defined as a system composed of a mixture of two or
more macromolecule which are essentially insoluble in each other
and differ in form .

4. History
• In 1962 Dr. Ray Bowen developed a new type of material known
as composite resin. The main innovation was a resin matrix of
Bisphenol-A-Glycidyl Methacrylate (Bis-GMA) and a fillers
agents. (silica,quartz,glass).
Dr. Ray Bowen

5. Composite restorative materials
Uses-
 Restoration of anterior and posterior teeth
 Used as a veneers material.
 To bulid up cores
 Cementation of orthodontic brackets,maryland bridges,ceramic
crowns,inlays ,onlays,laminates
 Pit and fissure sealants
 Repair of chipped porcelain restorations

6. Classification
1.Based on polymerization method
• Self cured.
• light cured,UV light cured ,Visible light cured
• Dual light cured.
• 2. According to Anusavice (Phillips)
Based on size of filler particles-
• Conventional 8-12 um
• Small particle 1-5 um
• Microfilled 0.04-0.4 um
• Hybrid 0.6-1.0 um

7. 3.Acco. To Marzoak 6 generations of composites:-
•First generation of composite
•Second generation of composite
•Third generation of composite
•Fourth generation of composite
•Fifth generation of composite
•Sixth generation of composite
4. Based on matrix composition
Bis-GMA
UDMA
Bis-EMA
TEGDMA
Other resin

8. 5) Based on Radiopacity
•Radiopaque
 Glasses with barium, strontium, or
lithium Ytterbium fluoride (YF3)
•Not radiopaque
•2 paste system -base & reactor. Chemically activated
•Single paste & liquid -chemically cured.
•Single paste system -supplied in syringes. Light activated.
•Disposable capsules -compomers
6 ) Based on mode of supply :

9. 7)According to Graham J. Mount; W.R. Hume :
T ype 1 - Macrofilled composite resin
T ype 2 - Microfilled composites resin
Type 3 – hybrid composite resin
8)Based on viscosity
Flowable composites.
Medium viscosity composites.
Packable composites
9).Classification based on area used
Anterior composite
Posterior composite

10. 10). Classification according to Bayne and Heyman:
•Megafill-1-2µm
•Macrofill-10-100µm
•Midifill-1-10µm
•Minifill-.01-.1µm.
•Microfill -0.04-0.4µm
•Nanofill-.005-.01µm

11. Midi -filler -
2 um
(beachball)
Mini -filler -
0.1 um
(canteloupe)
Nanofiller -
.02 um (pea)
Microfiller -
.04 um
(marble)
Relative Particle Sizes
(not to scale)

12. Composition
RESIN MATRIX
FILLER PARTICLES
COUPLING AGENT
THEY ALSO CONTAIN:
HYDROQUINONE
U.V ABSORBER
OPACIFIER
COLOUR PIGMENT

13. Resin matrix
• BIS-GMA resin is the base for composite. Diluents are
added to increase flow and handling characteristics or
provide cross linking for improved strength. Common
examples are:
• RESIN:- BIS-GMA bisphenol glycidylmethacrylate
• DILUENTS:- MMA methylmethacrylate
BIS-DMA bisphenol dimethacrylate
UDMA urethane dimethacrylate
• CROSS LINK DILUENTS
TEGDMA triethylene glycol dimethacrylate
EGDMA ethylene glycol dimethacrylate

14. FILLERS
•Silica particles
•Quartz
•Glass ( Ba, Sr, Zr)
If the composite is made up of the resin matrix AND fillers, it is called
Filled Resin

15. (1) reinforcement of the matrix resin, resulting in increased hardness,
strength, and decreased wear
(2) reduction in polymerization shrinkage
(3) reduction in thermal expansion and contraction
(4) improved workability by increasing viscosity
(5) reduction in water sorption, softening, and staining
(6) increased radiopacity
Benefits of fillers-

16. • Ground quartz-
Makes restoration difficult to polish and cause
abrasion of opposing teeth and restorations
• Colloidal silica—
Used in microfilled composites
Thicken the resin
• Glasses of ceramic containing heavy metals
Radiopacity
eg.Barium
Types of fillers used-

17. Coupling Agent
• Chemical bond
– filler particle - resin matrix
• transfers stresses
• Organosilane (bifunctional molecule)
– siloxane end bonds to hydroxyl groups on filler
– methacrylate end polymerizes with resin
CH3-C-C-O-CH2-CH2-CH2-Si-OH
CH2
O OH
OH
Bonds with filler
Silane
Bis-GMA
Bonds with resin
Phillip’s Science of Dental Materials 2003

18. Inhibitors
• Prevents spontaneous
polymer formation
– heat
– light
• Extends shelf life
• Butylated Hydroxytoluene
Phillip’s Science of Dental Materials 2003

19. Pigments and UV Absorbers
• Pigments
– metal oxides
• provide shading and opacity
• titanium and aluminum oxides
• UV absorbers
– prevent discoloration
– acts like a “sunscreen”
• Benzophenone
Phillip’s Science of Dental Materials 2003

20. Visible-Light Activation
• Camphorquinone
– most common photoinitiator
• absorbs blue light
– 400 - 500 nm range
• Initiator reacts with amine activator
• Forms free radicals
• Initiates addition polymerization
OCH2CHCH2O-C-C=CH2CH2=C-C-O-CH2CH-CH2O -C-
CH3 CH3
CH3
CH3OH OH
O O
Bis-GMA

21. Polymerization mechanism
1. Chemically activated
2. Light-activated

22. Two paste system
Base paste – benzoyl peroxide initiator
Catalyst paste– tertiary amine activator (N,N-dimethyl-p-toludine)
1.Chemically activated composite system

23. • Earliest system---UV light activated system
• Limitations –
Limited penetration of light into resin
Lack of penetration through tooth structure
2.Light activated composite resins—

24. Visible light activated system---
• Single paste system
• Photoinitiator – Camphoroquinone
• Amine accelerator – diethyl-amino-ethyl-methacrylate

25. Types of lamps used for curing
LED lamps. Using a solid-state, electronic process, these light
sources emit radiation only in the blue part of the visible
spectrum between 440 and 480 nm
QTH lamps. QTH lamps have a quartz bulb with a tungsten
filament that irradiates both LTV and white light that must be
filtered to remove heat and all
wavelengths except those in the violet-blue range (400 to 500
nm).

26. PAC lamps. PAC lamps use a xenon gas that is ionized to
produce a plasma.
The high-intensity white light is filtered to remove heat and
to allow blue light (400 to 500 nm) to be emitted.
Argon laser lamps- have the highest intensity and emit at a
single wave length.lamps currently avaialble emit 490 nm

27. •Consists of 2 light curable pastes
Benzoperioxide and aromatic tertiary amine
•Light curing – promoted by amine/CQ combination
•Chemical- amine/BPO interaction
APPLICATION:
•Cementation of bulky ceramic inlays
Dual Cure

28. High intensity curing
• High intensity lamps could provide savings in chair time.
• However high intensity, short exposure times cause accelerated
rates of curing, which leads to substantial residual stress build
up.

29. Depth of cure and exposure time
• Light absorption and scattering in resin composites reduces the
power density and degree of conversion (DC) with depth of
penetration
• Intensity can be reduced by a factor of 10 to 100 in a 2-mm thick
layer of composite which reduces monomer conversion to an
accceptable level.
• The practical consequence is that curing depth is limited to 2- 3mm
• Light attenuation vary from one type of composite to other
depending on opacity,filler size,filler concentration and pigment
shade

30. • Darker shades require long curing time
• When polymerising resin through tooth structure exposure time
should be increased by a factor of 2 – 3 to compensate for
reduction in light intensity
• For halogen lamps light intensity can decrease depending on
quality and age of light source,orientation of light tip,distance
between light tip and restoration and presence of
contamination,such as composite residue on light tip
• Despite the many advantages of light cured resins,there is still need
for chemically cured composites for eg chemicaly cured materials
can be used with reliable results as luting agent under metallic
restorations.

31. Polymerization
• Initiation
– production of reactive free radicals
• typically with light for restorative materials
• Propagation
– hundreds of monomer units
– polymer network
– 50 – 60% degree of conversion
• Termination
Craig Restorative Dental Materials 2002

32. C=
C
C=C C=C
C=C C=C
C=C C=C
C=C C=C
C=C C=C
C=C C=C
C=C C=C
C=C C=C
C=
C
C=
C
C=
CC=
C
C=
C
C=
C
C=
C
C=C C=C
C=C C=C
C=
C
C=
C
polymeriza
tion
Ferraca
ne

33. Degree of conversion
• DC is a measure of percentage of carbon-carbon double
bonds that have been converted to single bonds to form
polymeric resin
• The higher the DC the better the strength,wear,resistance
• Conversion values of 50%-70% are achieved at room
temperature for both types of curing system

34. Polymerization Shrinkage
Composites exhibit shrinkage while hardening.
More common when the restoration has extended onto root surface
results in gap formation.
Most imp regarding the effects of polymerization shrinkage is C-factor.

35. C--FACTOR
The C-factor is the ratio of bonded (flow-inactive) to unbonded or free (flow-
active) surfaces.
The ratio of the restorations bonded to unbonded ( free) surfaces.
C=BONDED WALLS/UNBONDED WALLS

36. Higher the C-factor , greater is the potential for bond
disruption from polymerization effects.
Class IV with C-factor 0.2 is at low risk compared to class I
with C-factor 5 is at high risk.

37. Incremental buildup and cavity configuration
• One technique is the attempt to reduce the so called C-
factor(configuration factor) which is related to the cavity
preparation geometry
• A layering technique in which restoration is built up in
increments , reduces polymerization stress by minimising the
Cfactor.
• Incremental technique overcomes both limited depth of cure
and residual stress concentration.

39. Conventional / traditional /macrofilled
composite
• Composition-
Ground quartz most commonly used filler
Average size : 8- 12 µm
Filler loading - 70-80 weight % or 50 – 60 vol %

40. Properties
• Compressive strength-
Four to five times greater than that of unfilled resins ( 250-300 Mpa)
• Tensile strength-
Double than of unfilled acrylic resins (50 – 65 Mpa)
• Elastic modulus-
Four to six times greater (8-15 Gpa)
• Hardness –
Considerably greater (55 KHN) than that of unfilled resins
• Coefficient of thermal expansion-
High filler –resin ratio reduces the CTE significantly.

41. • Esthetics –
Polishing result in rough surface
Selective wear of softer resin matrix
Tendency to stain
• Radiopacity –
Composites using quartz as filler are radioluscent
Radiopacity less than dentin

42. • Clinical considerations-
 Polishing was difficult
 Poor resistance to occlusal wear
 Tendency to discolor
 Rough surface tends to stain
 Inferior for posterior restorations

43. Microfilled composites
Developed to overcome surface roughness of conventional
composites
Composition-
Smoother surface is due to the incorporation of microfillers.
Colloidal silica is used as the microfiller
200—300 times smaller than the average particle in traditional
composites
Filler particles consists of pulverized composite filler particles

44. Properties
• Inferior physical and mechanical properties to those of
traditional composites
• 40 – 80 % of the restorative material is made up of resin
• Increased surface smoothness
• Areas of proximal contact- Tooth drifting
.

45. Compressive strength-
250- 350 Mpa.
Tensile strength-
30- 50 Mpa.
Lowest among composites
Hardness –
25- 30 KHN.
Thermal Expansion Coefficient-
highest among composite resins

46. Clinical considerations
• Choice of restoration for anterior teeth.
• Greater potential for fracture in class 4 and
class 2 restorations.
• Chipping occurs at margins.

47. Small particle composite
• Introduced in an attempt to have good surface smoothness and to improve
physical and mechanical properties of conventional composites.
Composition –
Smaller size fillers used-
Colloidal silica - present in small amounts ( 5 wt % ) to adjust paste viscosity
Heavy metal glasses . Ground quartz also used
Filler content
65 – 70 vol % or 80 – 90 %

48. Properties
• Due to higher filler content the best physical and mechanical properties are observed
• Compressive strength-
Highest compressive strength (350 – 400 Mpa )
• Tensile strength-
Double that of microfilled and 1.5 times greater than that of traditional
composites ( 75- 90 Mpa )

49. • Hardness –
Similar to conventional composites ( 50 – 60 KHN)
• Thermal expansion coefficient-
Twice that of tooth structure
• Esthetics –
Better surface smoothness than conventional because of small and highly
packed fillers
• Radiopacity –
Composites containing heavy metal glasses as fillers are radio-opaque which is
an important property in restoration of posterior teeth

50. Clinical considerations
• In stress bearing areas such as class 4 and class 2 restorations
• Resin of choice for aesthetic restoration of anterior teeth
• For restoring sub gingival areas

51. Hybrid composite
• Developed in an effort to obtain even better surface
smoothness than that provided by the small particle
composite.
• Composition –
2 kinds of fillers-
Colloidal silica –present in higher concentrations 10 – 20 wt
%
Heavy metal glasses – Constituting 75 %
Average particle size 0.4 – 1.0 µm

52. Properties
• Range between conventional and small particle
• Superior to microfilled composites
• Compressive strength-
Slightly less than that of small particle composite(300 – 350 Mpa )
• Tensile strength-
Comparable to small particle (70 – 90 Mpa )
• Hardness –
Similar to small particle ( 50 – 60 KHN )

53. • Esthetics –
Competitive with microfilled composite for anterior restoration
• Radiopacity –
Presence of heavy metal glasses makes the hybrid more radio-opaque than enamel

54. Clinical considerations
• Used for anterior restorations including class 4 because of its smooth surface and
good strength
• Widely employed for stress bearing restorations

55. Flowable composites
• Modification of SPF and Hybrid composites.
• Reduced filler level
• Clinical considerations-
Class 1 restorations in gingival areas.
Class 2 posterior restorations where acess is difficult.
Fissure sealants.

56. Composites for posterior restorations
• Amalgam choice of restoration for posterior teeth
• Mercury toxicity and increased esthetic demand.
• All types of composites except flowable composites
• Conservative cavity preparation
• Meticulous manipulation technique.