composites

composites

1. GOOD MORNING

2. COMPOSITES
(BASICS)

3. CONTENTS...
History
Definitions
Classification
Indications
Advantages
Composition
Each type
Mode of supply
Curing
Properties
Clinical technique
Tooth preparation
Acid etching
Insertion
Conclusion

4. HISTORY…
1855-vulcanite/ebonite
1868-John Wesley Hyatt-”celluloid”
1878-Thomas fletcher –Silicate cement
1937-Dr Walter Wright-methyl
methacrylate resin (acrylic resins)

5. 1955 Michael Buonocore
1962 Dr Rafael Bowen –
BisGMA
1970’s Microfilled
Composites
1972-Light Curing
1981 Hybrid composites
(Bayne, J Dent Educat, May 2005)

6. What is a composite?
Natural composite?
Dental composite?
synonyms

7. DEFINITION…
SKINNER’S
A highly cross linked polymericmaterial
reinforcedby a dispersion of amorphous
silica, glass, crystalline or organic resin
filler particles and/or short fibers bonded
to the matrix by a coupling agent.

8. DCNA
A 3 dimensionalcombination of at least two
chemically differentmaterials with a
distinct interfaceseparating the
components.

9. McCABE
A composite material is a product which
consists of at least two distinct phases
normally formed by blendingtogether
components having different structures
and properties.

10. INDICATIONS...
Class I, II, III, IV, V, VI
core buildups
Sealants and preventive resin
restorations
Esthetic enhancement
procedures
Cements
Veneering metal
crowns/bridges
Temporary restorations

11. Periodontal splinting
Non caries lesions
Enamel hypoplasia
Composite inlays
Repair of old composite
restoration
Patients allergic to metals

12. CONTRAINDICATIONS…
Isolation
Occlusion
Subgingival area/root surface
Poor oral hygiene
High caries index
Habits (bruxism)
Operator abilities

13. ADVANTAGES…
Esthetics
Conservation
Less complex
Insulative
Used almost universally
Strengthening
Bonded to tooth
structure
Retention
Microleakage
staining
Repairable
No corrosion

14. DISADVANTAGES…
Polymerization shrinkage
Technique sensitive
Higher coeff. Of thermal expansion
Difficult, time consuming
Increased occlusal wear
Low modulus of elasticity
Bio-compatibility ??
Staining
Costly

15. CLASSIFICATION…
ADA Specification No. 27 (JADA Vol 94, Jun 1977)
Type I
Type II
REQUIREMENTS
•Working time
•Hardening time
•Opacity
•Colour stability
•Tensile strength
•Water sorption at 37°C

16. classification…
SKINNER’S (10
th
ed)
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

17. ANUSAVICE (Skinner’s-11
th
ed)

18. classification…
STURDEVANT
As per filler size
Megafill-βquartz , large
size
Macrofill –10-100 m
Midfill –1-10 m
Minifill –0.1-1 m
Microfill –0.01-0.1 m
Nanofill –0.005-0.01 m
Hybrids
Homogenous/heterogenous
Modified composites
By weight or volume percent

19. As per filler size

20. As per weight /vol percent

21. Particle size distribution

22. Chronology
MACROFILLED
FINE PARTICLE :Traditional/conventional-8-
10 µm
FINE FINISHING:Microfilled-0.02-0.04µm
Homogenous
heterogenous
HYBRIDS-2-5 µm
Minihybrids-0.1-1 µm

23. classification…
MARZOUK-generations
1
st
-Macro ceramics
2
nd
-Colloidal silica
3
rd
-Hybrid :macro and micro colloidal ceramics
4
th
–Hybrid : heat cured irregularly shaped
5
th
-Hybrid : heat cured spherical
6
th
-Hybrid : agglomerates of sintered micro ceramics

24. classification…
CRAIG
TYPE I-polymer materials for occlusal
TYPE II-other polymer-based materials
Class 1: self cure
Class 2:light cure
•Group 1
•Group 2
Class 3:dual cure

25. classification…
FERRACANE
Types Filler Size Volume
Conventional
Quartz
Glass
Avg: 20 m
Range: 1-100 m
50-60%
Microfill
Fused silica
SiO
2
Avg: 0.04 m
Range: 10-50 m
30-55%
Small hybrid Quartz / Glass
Avg: 0.5-1.0 m
Range: 0.1-3 m
50-65%
Midsize hybridQuartz / Glass
Avg: 1.0-3.0 m
Range: 0.1-10 m
65-70%

26. classification…
DCNA (Leinfelder K. Apr 1985)
Conventional composite –15 -35 m
Intermediate composite –1-5m
Microfilled composite –<0.04m
DCNA (Jan 2001)
Type I-microfill with fumed silica
Type II-others with crushed quartz/glass

27. classification…
LUTZ & PHILIPS
(J. Prosth Dent. Oct 1983)
Macrofilled
Microfilled
Homogeneous
Splintered
Spherical
Agglomerated
Hybrid

29. classification…
WILLEM’S (Dental Materials,
Sept 1992)
Densified
Midway filled
•Ultra fine-anterior teeth
•Fine
Compact filled
•Ultra fine-posterior teeth
•Fine
Homogeneous microfine
Heterogeneous microfine
Miscellaneous
Traditional
Fibre-reinforced

30. classification…
G.J. PEARSON (Dental Update, Sept,1991)
Conventional
Microfine
Hybrid

31. classification…
Based on inorganic
loading
Heavy filler material –
75%
Lightly filler material –
66%
Based on their area of
application
Anterior
Posterior
Based on method of
curing
Chemical
Light cure
UV
Visible
staged
Heat cure
Dual cure

32. Based on consistency
Light body –flowable
Medium body –Homogenous microfills, macrofills and
midifills
Heavy body –packable Hybrid minifills
Based on Matrix
Composites based on BisGMA
Composites based on UDMA

33. COMPOSITION…
MAJOR COMPONENTS
RESIN
MATRIX
INORGANIC
FILLERS
COUPLING
AGENT

34. OTHER
COMPONENTS
Activator initiator
system
Colour stabilizers
Inhibitors
Optical modifiers
Pigments

35. Resin matrix…
PRINCIPAL MONOMERS
BIS-GMA-aromatic-1962-”BOWEN’S RESIN”
Modified BIS-GMA
UDMA-1974 (Foster and Walker)
DILUENT MONOMERS
TEGDMA-aliphatic
EGDMA
HEMA
NEW MONOMERS

36. 2,2-bis[4(2-hydroxy-3 methacryloyoxy-propyloxy)-phenyl]propane

37. Inorganic fillers…
Improves material properties
Benefits of fillers:
Reinforcement of matrix-strength, hardness
wear, polymerization shrinkage-3%
thermal expansion, heat evolved
viscosity, radiopacity
water sorption
Contribute to esthetics

38. “Filler loading”
52-88% wt
30-70% vol-74% max
Filler surface area
50-400 m
2
/gm

39. CLASSIFICATION:
Materials used
Filler sizes & its distribution
shape
Filler volume
Radiopacity
Hardness

40. MATERIALS USED:
Pure silica
Crystalline Non-crystalline
Crystobalite
Tridymite
quartz
Glass
Modifications by ions:
Li, Al
Ba, Zn, Y, St, Zr, B
Disadvantages
Egs

41. GROUND QUARTZ FILLER

42. Amorphous silica
Colloidal silica
Pyrolytic/precipitation
process-
Pyrogenic/fumed silica
Agglomerated silica-1-25
m

43. PYROGENIC SILICA

44. Organic fillers
Fibre fillers
Single crystals-SiC
Crystalline polymers

45. FILLER SIZES
Mega, macro, midi, mini, micro,
nano
Marzouk:
Macro-ceramics
Colloidal & micro-ceramics
Fabricated macro-reinforcing
phases & colloidal micro-ceramic
Properties-fluidity
-surface roughness-
0.2-0.6 m

46. FILLER DISTRIBUTION (Lopes et al, J Esthet & Restor Dent 2004)
Hybrids-0.04-3 m (Avg 1-3 m),
-7-15% microfillers
Microhybrids –Avg 0.8-1 m
-polishable, mech properties, uniform filler load
Minifilled Hybrids-Avg 0.4-0.6 m
-easy to light cure, polishability
CONTINUUM -FILLED MATERIAL-66% synthetic Zr/Si
-0.01-3.5 m (0.6m)
Hybrid:
ClearFil
Microhybrid:
TPH Spectrum
Minifilled hybrid:
Vitalescence

47. FILLER SHAPES
Large spherical particles
Large irregularly shaped particles
Blends
Refractive index

48. Coupling agents…
TYPES
Organosilanes
(-methacryloxypropyl
trimethoxy silane)
Titanates
Zirconates
REACTION
FUNCTIONS

49. Activator-initiator system…
CHEMICALLY ACTIVATED
Benzoyl peroxide initiator (universal paste)
Aromatic tertiary amine activator (N,N, dimethyl-p-
toluidine)(catalyst paste)
LIGHT ACTIVATED
Camphoroquinone -0.2%-1%
Organic aliphatic amine –dimetylaminoethyl methacrylate
(DMAEMA)-0.15%
Blue light

50. Inhibitors, optical modifiers…
INHIBITORS
Butylated hydroxytoluene (BTH)-0.01%
Functions
OPTICAL MODIFIERS
Pigments-metal oxides
Opacifiers-titanium & aluminum oxide-0.001-0.007%
Darker shade & opacifier-thin layers
UV light absorbers

51. TYPES OF COMPOSITES…
4 TYPES
TRADITIONAL
HYBRIDMICROFILLED
SMALL-PARTICLE

52. Traditional composites…
1970s.
Amorphous silica & quartz (8-12m)-60-70% vol.
Indications

53. ADVANTAGES DISADVANTAGES
Compressive, tensile
strength
Stiffness
Hardness
Polymerization shrinkage
Water sorption, thermal
expansion
Polishability
Surface roughness
Staining, plaque
Occlusal wear
Poor esthetics

54. Small particle composites…
Filler size 0.5-3 m
(65-77 % vol)
Glass particle with
heavy metals &
colloidal silica
Indications

55. ADVANTAGES DISADVANTAGES
Good mech properties
Good smoothness
Wear resistance
Less polymerization
shrinkage
Radioopacity
prone to wear and
deterioration.

56. Microfilled composites…
Colloidal silica –0.04
m -20-59 % vol
Agglomerates
Sintering of colloidal
silica
Prepolymerized
composite fillers

57. ADVANTAGES DISADVANTAGES
Best surface
finish
Excellent wear
resistance
Tensile strength
Water sorption and
CTE
fracture resistance
Radioluscent
Polymerization
shrinkage

58. Hybrid composites…
Fillers
0.4-1m –60-65 % vol
Colloidal silica (10-20 wt%)
Glass particles with heavy metals (75-80 wt%)
Intermediate properties
Indications

59. ADVANTAGES DISADVANTAGES
Good physical
properties
Improve wear
resistance
Superior surface
morphology
Good esthetics
Increased
surface roughness
with time

60. CHARACTERISTIC
PROPERTY
UNFILLED
ACRYLIC
TRADITI
ONAL
SMALL
PARTICLE
HYBRID MICROFILL
ED
Size (m) - 8-12 0.5-3 0.4-1.0 0.04-0.4
Inorganic filler
(vol%)
0 60-70 65-77 60-65 20-59
Inorganic filler
(wt%)
0 70-80 80-90 75-80 35-67
Compressive
strength (MPa)
70 250-300350-400300-350 250-350
Tensile strength
(MPa)
24 50-65 75-90 40-50 30 -50
Elastic modulus
(GPa)
2.4 8-15 15-20 11-15 3-6
TEC (ppm/ °C) 92.8 25-35 19-26 30-40 50-60
Water sorption
(mg/cm
2
)
1.7 0.5-0.70.5-0.6 0.5-0.7 1.4-1.7
Knoop hardness
(KHN)
15 55 50-60 50-60 25-35
Curing shrinkage
(vol%)
8-10 - 2-3 2-3 2-3
Radio
opacity(mm\Al)
0.1 2-3 2-3 2-4 0.5-2

61. TRADITIO
NAL
SMALL
PARTICLE
MICROF
ILLED
HYBRID
Mechanical
Polymerization
shrinkage
x
Polishability x
Wear
resistance
Esthetics x
Use in
posteriors
x x
a



  





  

   

62. MODE OF SUPPLY…
Basic six systems
Chemically cured paste-paste
Chemically cured / Photo cured liquid-powder
Chemically cured / Photo cured paste –liquid
Photo cured one pastesystem
Photo cured one liquidsystem
Chemically cured 3 / 4 partsystem

63. For chemical cure-
syringes/tubs
For light cure-
spills/syringe/compules

64. CURING OF COMPOSITES…
POLYMERIZATION

65. CHEMICAL ACTIVATION
Chemistry
Advantages
Even polymerization-75%
Disadvantages
Oxygen inhibition
Working time

66. LIGHT ACTIVATION
UV light
Visible light
Advantages
Easy to use, single paste
Less porosity
Less sensitive to oxygen
Command polymerization
Colour stability, colors can be
optimized
Better mech properties
Setting time –faster cure

67. Disadvantages
Increments
Time consuming
Poor accessibility
Variable exposure
Sensitive to ambient light
Shrinkage
Ocular damage
Cost

68. Comparison
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 workingtime Working time under control
Shrinkagetowards centre of bulkShrinkage towards light source
Air may get incorporated Less chance of air entrapment
More wastage of material Less wastage
Not properly finished Better finish

69. DUAL CURING
2 light cure pastes-syringes/tubs
Chemistry
Indications
Disadvantages
EXTRAORAL CURING

70. CURING LAMPS…
1970’s-”Nuva Light”
Disadvantages
Types of devices
4 sources of light
CURING
SYSTEMS
UV LIGHT VISIBLE LIGHT

71. Counter top units
Gun type units-features
Types of devices…

72. Counter top units
Gun type units
Fiber optic handpiece curing attachments
Smaller diameter of light guide
Less intense light source
Periodic need for replacement of fiber optic
cords.

73. Quartz-Tungsten-Halogen
units
CONVENTIONAL HALOGEN
CURING LAMPS
E.g.: Optilux 500
Advantages
Less cost
Simple, well known
technology
Little/no heat

74. Disadvantages
Slow cure time
Plug into electricity
Large, cumbersome
Decreased output
Replace lamp
Light guides

75. ENHANCED/ FAST HALOGEN
LIGHTS(Christensen;JADA,Jun 2002)
E.g.: Optilux 501-TurboTip
Advantages
Faster cure
Proven technology
Disadvantages
Narrower light guide
Generate heat
Higher cost

76. HIGH-INTENSITY HALOGEN LIGHTS
(Christensen;JADA,Apr 2004)
E.g.: Swiss Master light
Very intense light
Water-cooling
Advantages
Built-in radiometer
Disposable curing tips
Faster curing
Experimental

77. Plasma arc units
Advantages
Curing time-3 sec
Short procedure
Disadvantages
Heat production
High cost
Replacement costly
Large, bulky

78. Argon laser units
ADVANTAGES
Correct wavelength
Deeper & faster curing
Better mech properties
Decreased sensitivity to curing tip
distance
Less post-op sensitivity & discomfort
DISADVANTAGES
Increased shrinkage, brittleness
Marginal leakage
Heat increase on surface
Expensive
Bulky equipment

79. LED units
ADVANTAGES
Cordless,light weight
Long lasting
No heat
Moderate curing time
Quiet
DISADVANTAGES
New technology
Slower than PAC
Batteries must be recharged
Higher cost
Low intensity

80. Light curing variables
Spectral output

81. Light curing variables

82. Procedural factors

83. Energy required: -16 J/cm
2
for 2mm
-40 sec x 400 mW/cm
2
Light attenuation: opacity, filler size, pigment
shade, tooth structure -“SOGGY BOTTOM”
QTH, PAC, Laser-(> 1000mW/cm
2
)
Depth of cure-increases
Time of exposure-decreases
Increases degree of conversion in deeper areas

84. Degree of conversion
% of C-C double bonds that have
been converted to single bonds to
form polymeric resin
Strength, wear resistance
Avg 50-60%, light cure-44-75%
Cross linked , pendant, free groups
Factors
Light curing: more shrinkage stress
Staining
Sensitivity
Secondary caries

85. polymerization shrinkage
Value: 1-4% , stress:
17MPa
Prevents bonding to
dentin-strength required
Causes stress to develop
Externally: interface of
restoration & tooth
Internally: between filler and
resin
Inelastic deformation of tooth
(Sakaguchi, Dent Mat, 2005)

86. Factors affecting stress
development
Restorative technique
Modulus of resin elasticity
Polymerization rate
Cavity configuration

87. Cavity configuration
Ratio of bonded to non-
bonded surface
Use of incremental/layering
technique

88. REDUCTION OF RESIDUAL
STRESS…
Reduction in vol contraction by alteration of chemistry
Low shrink monomers
Clinical techniques
Curing rate control
Incremental build-up
Resin based composite systems
Dentin-enamel adhesive systems
Using material which flows
Material with low modulus of elasticity
Introduction of air bubbles
Combe & Burke,
Dental update2000
Deliperi & Bardwell
JADA, Oct 2002

89. Curing techniques

90. SOFT START-Mehl et al (1997)
10sec-150 mW/cm
2
30-50 sec-700mW/cm
2
150mW/cm
2
increase to 1130
mW/cm
2
in 10 sec
Constant for 10 sec

91. HIGH ENERGY PULSE CURING
400 mW/cm
2
-10 or 20 sec
Delay -10 or 20 sec
400 mW/cm
2
-10 or 20 sec
PULSE DELAY CURING
3 sec -200 mW/cm
2
Delay -3-5 min, finish
30 sec -600 mW/cm
2
Advantages of soft start

92. Placement techniques
(Deliperi & Bardwell, JADA,Oct 2002)
PLACEMENT TECHNIQUES
INCREMENTAL
TECHNIQUES
DIRECTED SHRINKAGE
TECHNIQUE
BULK TECNIQUE
Horizontal technique
Three-site technique
Oblique technique
Successive cusp build-up technique
Modified successive cusp build-up
Split incremental technique

93. TRANS-ENAMEL POLYMERIZATION
(Belvedere, DCNA, Jan 2001)

94. THREE-SITE TECHNIQUE

95. OBLIQUE TECHNIQUE

96. SUCCESSIVE CUSP BUILD -UP TECHNIQUE
(Leibenberg, 1996)

97. SPLIT INCREMENTAL TECHNIQUE
(Hassan & Khier, General dentistry, Nov-Dec 2005)

99. PROPERTIES…
PROPERTIES
PHYSICAL MECHANICAL CLINICAL
Working, setting time
Polymerization
shrinkage
Thermal properties
Water sorption
Solubility
Colour stability
Wear
Depth of cure
Radiopacity
Biocompatibility
Staining
Secondary caries
Marginal integrity
Post-op sensitivity
Flexural strength
Compressive strength
Knoop hardness
Bond strength
Rigidity
Fracture toughness
creep

100. Physical properties
WORKING & SETTING TIME
Light cure: surface hardens in 60-90 sec
Chemical cure: 3-5 min
POLYMERIZATION SHRINKAGE
Light cure: 60% in 60 sec
Debonding, cusp fracture
Macrofilled:1-2.5%
Microfilled:2-3.5%
Microhybrid:0.6-1.4%
Chemical cure: even, towards centre

101. THERMAL PROPERTIES
Places additional strain on
bond-percolation
Values for tooth, amalgam,
unfilled resins, composites
COLOUR STABILITY
Stains
Change of colour
Stress cracks
Debonding of filler
Oxidation
Water sorption
WATER SORPTION &
SOLUBILITY
Macrofilled: 0.-1.1 mg/cm
2
Microfilled: 1.5-2 mg/cm
2
Solubility: 0.01-0.06 mg/cm
2
Benefits
Colour instability, leaching,
less wear resistance

102. Mechanical properties
FLEXURAL STRENGTH &
MODULUS
50% less for microfilled,
flowable composites
Thus used in cervical lesions
COMPRESSIVE STRENGTH
Similar for all (240-290 MPa)
Transverse strength-45-125
MPa
KNOOP HARDNESS
Hybrid: 35-65 KHN
Microfilled: 18-30 KHN
BOND STRENGTH
For enamel, dentin
For other substrates

103. RIGIDITY
Microfilled: 4-8 GPa
Hybrid: 8-19 GPa (similar
to dentin)
Large MOD restorations
CREEP
Microfilled: creep
FRACTURE
TOUGHNESS
Resistance to crack growth
Microfilled: 0.7-1.2 MNm
-
1.5
Hybrid: 1.4 –2 MNm
-1.5
Decreases with time

104. Clinical properties
WEAR
Types-CFA, OCA, FCA,
PCA, toothbrush, fatigue
4 mechanisms
Microfracture theory
Hydrolysis
Chemical degradation
Protection
Macro & microprotection
Wear of opposing enamel

105. DEPTH OF CURE
Increasing depth
Increased time
Heavily filled
Microfilled & hybrid
Light & translucent shade
Efficiency of light
Distance of tip
Through tooth
Conc of photoinitiator
“step” the light for large
restorations
Large tip-more time-60 sec

106. RADIOPACITY
To detect secondary
caries
By Ba, Strontium, Zr
glasses
Should be > enamel

107. BIOCOMPATIBILITY
Inherent toxicity-BPA
(xenoestrogenic), HEMA-
allergenic
Marginal leakage
Activation light
Gingival tissue

108. MARGINAL INTEGRITY
5 ways to reduce (Cheung, J prosth Dent,1990)
Acid etch technique
Dentin bonding
Cavity design
Incremental technique
Sealing the margins-unfilled resin
Staining, Secondary caries, Post-op
sensitivity

109. CLINICAL TECHNIQUE…
Local anesthesia
Preparation of operating
site
Shade selection
Isolation
Rubber dam
Cotton rolls
Gingival retraction cord
Preoperative wedging
INITIAL PROCEDURES

110. Tooth preparation
CONVENTIONAL
DESIGN
Indications

111. BEVELED
CONVENTIONAL
Indications
Advantage of
beveling

112. MODIFIED BOX-ONLY
FACIAL/
LINGUAL SLOT

113. Bevels
Partial bevel
Long bevel
Hollow ground bevel
Scalloping
Skirting
Axial bevel tech
(Leibenberg, Quint Int, 2000)

114. Restorative procedures
Pulp protection
Acid etching
Application of primer, adhesive
Matrix placement
Inserting the composite
Contouring the composite
Polishing

115. Acid etching…
1955-Michael Buonocore
Effects of acid etching
Removes interprismatic, tops,
sides
Increases surface area and
energy
Irregularities, depressions-25
µm
Exposes proteinaceous material
Removes deposits, plaque
Polar phosphate group added
Requirement for etching

116. Etching patterns-4 types
Silverstone (1974)
Etched zone
Qualitative porous zone
Quantitative porous zone
Macrotags, microtags
TYPE I TYPE II MIXED TYPE

117. SUBSTANCES USED
PHOSPHORIC ACID
>50% -monocalcium phosphate
monohydrate
< 27% dicalcium phosphate
monohydrate
Citric acid -10%
Polyacrylic acid-40%
Maleic acid
Nitric acid-2.5%
With ferric oxalate
With aluminium oxalate
Pyruvic acid + glycine
Hydrochloric acid
Lactic acid
Monohydroxy carboxylic acid
α-ketocarboxylic acid

118. Bond strength-18-22 MPa
Mode of supply
Liquid
Gel
Etching time

119. Application of primer,
adhesive
Matrix placement
Palodent
Compositight matrix
system
Tofflemire
Polyester strips

120. Insertion of the material

121. Finishing of the restoration

122. REPAIR OF COMPOSITES…
OLDER
RESTORATION
Etch, primer,
adhesive, composite
Bond strength-50%
FRESHLY
POLYMERIZED
If not yet contoured
Directly place
composite
If contoured and
polished
Re-etch, adhesive,
composite

123. COMMON PROBLEMS…
Poor isolation
White line or halo around enamel margin
Voids
Missing proximal contacts
Incorrect shade
Poor retention
Contouring and finishing problem

124. LONGIVITY OF COMPOSITES…
Roulet, J of Dent, 1997
Amalgam –0.3-6.9% -20 yrs
Composites-0.5-6.6% -10yrs
Chadwick (2001)
Amalgam-94.5 % after 7 yrs
Composites-67.4% after 7 yrs

125. CONCLUSION

126. THANK YOU
“The world hates change, yet it is the only thing
that has brought progress.”
-Charles Kettering