Classification of Composites
CLASSIFICATION OF COMPOSITES
The classifications mentioned are of:
Skinners
Marzouk
J-Dental Update 1991 (size and type of fillers)
According to Sturdevant
According to Ferracane
According to Lutz and Phillips
According to Willem’s
According to DCNA 1981
According to DCNA 2001
According to Anusavice
1) SKINNERS HAS CLASSIFIED COMPOSITES BASED UPON
THE AVERAGE PARTICLE SIZE AS:
Composite Particle size
i. Traditional composite (macrofilled) 8-12µm
ii. Small particle-filled composite 1-5µm
iii. Microfilled composite 0.04-0.4µm
iv. Hybrid composites 0.6-1.0µm
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Classification of Composites
2) Marzouk on the other hand has classified composites as
generations depending on the order of their chronological
development.
Prior to discussing the generations elucidated by Marzouk it
is important to note the two main phases present in a composite
resin. So, as Marzouk states, although a variety of composite resins
are now available to the dental profession, they are all dependent
upon the original ideal of Raphael Bowen. Composites are all
reinforced materials with:
1. A continuous (dispersion/reinforced) phase.
2. An interrupted (dispersed/reinforcing) phase.
The continuous phase – Consists of the synthetic resin
macromolecules, i.e. it is a reaction product of Bisphenol A and
glycidyl methacrylate.
Other substitutes for BIS-GMA are:
i. Modified BIS-GMA – by elimination of OH group.
ii. Urethane diacrylate.
iii. TEG-DMA.
Polymerization of this continuous phase brings about
hardening of the material which is inturn bought about by the
initiators and activators.
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Classification of Composites
The interrupted phase:
This may consist of either one or combination of the following:
i. MACRO- CERAMICS.
ii. COLLOIDAL and MICRO-CERAMICS.
iii. Fabricated macro reinforcing phase with colloidal
micro-ceramic base.
i. Macro-Ceramics – Consists of silicate-based materials (SiO 4 ),
e.g. quartz, fused silica, silicate glasses, crystalline lithium
aluminium silicate, (Radio-opaque) Ba-Al-boro-Si etc.
ii. Colloidal and Micro-Ceramics: Originally these consisted of
colloidal silicate forms but have now been replaced by larger
sized pyrogenic silica. The colloidal silica (as silicic acid) –
formulated by a chemical process of hydrolysis and
preparation colloidal form diameter – not more than 0.04
micrometers.
iii. Colloidal or micro-ceramics are introduced into partially
thermo-chemically polymerized spherical particles of a resin
system. These highly reinforced spherical resin particles are
then used as reinforces for a continuous phase resin, forming
a continuous resin. The interphase between the continuous and
interrupted phase is the most crucial in determining the final
behavior of these composite systems.
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Classification of Composites
Therefore, chronologically we have:
i. First Generation Composites:
- Consist of macroceramic reinforce phases.
- Highest surface roughness.
- Highest proportion of destructive wear clinically (due to
dislodging of large ceramic particles).
- Drawbacks reduced by use of smaller, soften particles of
variable dimensions.
ii. Second Generation Composites:
- With colloidal and micro-ceramic phases.
- Best surface texture of all composites.
- Strength and coefficient of thermal expansion are
unfavourable because of limited % age of reinforced.
iii. Third Generation of Composite:
- Hybrid composite.
- Combination of macro and microcolloidal ceramic reinforced
in ratio of 75:25%.
- Properties are intermediate to Ist and 2 n d generations.
iv. Fourth Generation of Composites:
- Also, a hybrid composite.
- But instead of macro ceramic fillers they contain heat cured,
irregularly shaped highly reinforced composite macroparticles
with a reinforcing phase of microceramics.
- Fourth generation composites are very technique sensitive.
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Classification of Composites
v. Fifth Generation Composites:
- Hybrid composite.
- Continuous phase is reinforced with microceramics and
macro, spherical, heat cured highly reinforced composite
particles.
- The spherical shape of these macro ceramics improves their
wettability and consequently their chemical bonding to the
continuous phase of the final composite.
vi. Sixth Generation Composites:
- Hybrid type.
- Continuous phase is reinforced with a combination of micro-
ceramics and agglomerates of sintered microceramics.
3) CLASSIFICATION OF COMPOSITES BASED ON SIZES
AND TYPE OF FILLERS (G.J. PEARSON : DENT UPDATE
1991):
Composites are divided into 3 categories by the size and type
of their fillers. They are:
i. Conventional composites.
ii. Microfine.
iii. Hybrid.
i. Conventional composites:
- The fillers in these is now usually radiopaque barium or
strontium glass with particle sizes in range between 2.5-5µm.
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Classification of Composites
- Disadvantage poor union to resin and therefore breakdown of
restoration.
ii. Microfine composites:
- The filler particles here viz. Colloidal silica are about 200
times smaller than the conventional products. (These
composites have a higher proportion of resin therefore
increased polymerization shrinkage and potentially more bulk
wear).
iii. Hybrid composites:
- The filler particle size here is carefully defined and graded to
give varying proportion of large, medium and fine sized
particles.
- The merit of this gradation is to provide maximum packing of
the filler (vol fraction 70%).
4) Classification based on SIZE OF FILLERS as mentioned in
STURDEVANT:
(K. Leinfelder).
1. Megafill composites - Megafillers – quartz, very large size.
2. Macrofill composites - Macrofillers – 10-100µ.
3. Midifill composites - Midifillers – 1-10µ.
4. Minifill composites - Minifillers – 0.1-1µ.
5. Microfill composites - Microfillers – 0.01-0.1µ.
6. Nanofill composites - Nanofillers – 0.005-0.01µ.
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Classification of Composites
Fig 4.1: Filler particle size of different composite classes.
5) ACCORDING TO DCNA 1981
Conventional composite – 15 - 35 mm
Intermediate composite – 0.5 - 1 mm
Microfilled composite – 0.009 - 0.9 mm
6) ACCORDING TO DCNA (Jan 2001)
Type I-microfill with fumed silica
Type II-others with crushed quartz/glass
8) ACCORDING TO LUTZ & PHILIPS (J. Prosth Dent. Oct
1983)
Macrofilled
Microfilled
Homogeneous
Splintered
Spherical
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Classification of Composites
Agglomerated
Hybrid
Fig 4.2: Lutz & Philips classification of composites according to
fillers
9) ACCORDING TO CRAIG
Type I
o Class I macrosized particles 8-25 m
o Class II minisize particles 1-8 m
o Class III microsize particles 0.04-0.2 m
o Class IV blend of micro & macro particles 0.04-10 m
Type II
o Class I macrosized 10-20 mm i.e., organic particles in
unreinforced resin matrix.
o Class II macro sized unreinforced particles 10-20 m
i.e., organic filler particles in reinforced resin matrix
10) ACCORDING TO WILLEM’S
Densified composite resins
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Classification of Composites
o Midway filled
Ultra fine (<3 mm)
Fine (>3 mm)
o Compact filled
Ultra fine (<3 mm)
Fine (>3 mm)
Miscellaneous composite resins
o Prepolymerized resin and inorganic fillers
Heterogeneous microfine composite
o Contains spherical polymerized fillers
Fig 4.3: Willem’s classification of dental composites.
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Classification of Composites
11) ACCORDING TO FERRANCE
Types Filler Size Volume
Conventional Quartz Glass Avg: 20 mm
Range: 1-100 mm 50-60% Microfill Fused silica
SiO2 Avg: 0.04 mm Range: 10-50 mm 30-55%
Small hybrid Quartz / Glass Avg: 0.5-1.0 mm Range: 0.1-3 mm
12) BASED ON METHOD OF CURING
Chemical
Light cure
UV
Visible
Dual cure
13) ACCORDING TO ANUSAVICE (11 T H EDITION)
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Classification of Composites
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